.. index:: ! gmt.conf
Configuration for GMT
The following is a list of the parameters that are user-definable in GMT. The parameter names are always given in UPPER CASE. The parameter values are case-insensitive unless otherwise noted. Theme-independent system defaults are given in brackets [default is value], with units specified for dimensional quantities, while theme-dependent defaults are outlined in the GMT_THEME :doc:`settings table <theme-settings>`. Most parameters can be changed by using :doc:`gmtset`, editing a gmt.conf file that can be acquired using :doc:`gmtdefaults`, or setting parameters on-the-fly via the --PARAMETER=VALUE option to any GMT program. However, a few are static and are only read via the gmt.conf file; these are labeled (static). Several parameters take only true or false. It is recommended that users specify the units for distances and lengths by appending c (cm), i (inch), or p (points) when changing parameters using any of these methods. By default, when no unit is specified the value will be assumed to be cm for parameters not related to fonts or pen thicknesses and will be assumed to be points for parameters related to fonts or pen thicknesses. The interpretation of unitless dimensional quantities can be changed using the parameter :term:`PROJ_LENGTH_UNIT` or specifying US units when building GMT.
The full explanation for how to specify pens, pattern fills, colors, and fonts can be found in the :doc:`gmt` man page.
| THEMATIC SUB-SECTIONS | prefix |
|---|---|
| COLOR Parameters | COLOR_ |
| DIR Parameters | DIR_ |
| FONT Parameters | FONT_ |
| FORMAT Parameters | FORMAT_ |
| GMT Miscellaneous Parameters | GMT_ |
| I/O Parameters | IO_ |
| MAP Parameters | MAP_ |
| Projection Parameters | PROJ_ |
| PostScript Parameters | PS_ |
| Calendar/Time Parameters | TIME_ |
.. glossary::
**COLOR_BACKGROUND**
Color used for the background of images (i.e., when z < lowest color
table entry) [default is **black**]. **Note**: If the current CPT
has a specification for background color then that takes precedence.
**COLOR_FOREGROUND**
Color used for the foreground of images (i.e., when z > highest
color table entry) [default is **white**]. **Note**: If the current CPT
has a specification for foreground color then that takes precedence.
**COLOR_CPT**
Default CPT table when none is selected [default is **turbo**]. **Note**:
Grids with a default CPT in the header will ignore this setting.
**COLOR_HSV_MAX_S**
Maximum saturation (0-1) assigned for most positive intensity value
[default is **0.1**]. **Note**: The default is most suitable for paper
printing. Use 0 for all digital imagery.
**COLOR_HSV_MIN_S**
Minimum saturation (0-1) assigned for most negative intensity value
[default is **1.0**].
**COLOR_HSV_MAX_V**
Maximum value (0-1) assigned for most positive intensity value
[default is **1.0**].
**COLOR_HSV_MIN_V**
Minimum value (0-1) assigned for most negative intensity value
[default is **0.3**]. **Note**: The default is most suitable for paper
printing. Use 0 for all digital imagery.
**COLOR_MODEL**
Selects in which color space a CPT should be interpolated.
By default, color interpolation takes place directly on the RGB
values which can produce some unexpected hues, whereas interpolation
directly on the HSV values better preserves those hues. The choices
are: **none** (use whatever the **COLOR_MODEL** setting in the
CPT demands), **rgb** (force interpolation in RGB),
**hsv** (force interpolation in HSV), or **cmyk** (assumes colors are
in CMYK but interpolates in RGB) [default is **none**].
**COLOR_NAN**
Color used for the non-defined areas of images (i.e., where z = NaN)
[default is **128**]. **Note**: If the current CPT has a color
specification for NaN values then that takes precedence.
**COLOR_SET**
Default comma-separated list of colors (or a *categorical* CPT name) for
automatic, sequential color assignments
[default is **#0072BD,#D95319,#EDB120,#7E2F8E,#77AC30,#4DBEEE,#A2142F**].
.. glossary::
**DIR_CACHE**
Cache directory where we save remote cache filenames starting in **@**
(e.g., @hotspots.txt) [default is **~/.gmt/cache**].
**DIR_DATA**
Session data directory. Overrides the value of the environment variable
**$GMT_DATADIR** (see :ref:`Directory parameters` in the Technical Reference).
**DIR_DCW**
Path to optional Digital Chart of the World polygon files.
**DIR_GSHHG**
Path to GSHHG files. Defaults to **$GMT_SHAREDIR**/coast if empty.
.. glossary::
**FONT**
Sets the default for all fonts, except :term:`FONT_LOGO`. This setting
is not included in the **gmt.conf** file.
**FONT_ANNOT**
Sets both :term:`FONT_ANNOT_PRIMARY` and :term:`FONT_ANNOT_SECONDARY` to
the value specified. This setting is not included in the **gmt.conf** file.
**FONT_ANNOT_PRIMARY**
Font used for primary annotations, etc [default is :doc:`theme dependent
<theme-settings>`]. When **+** is prepended, scale fonts, offsets and
tick-lengths relative to :term:`FONT_ANNOT_PRIMARY`. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**FONT_ANNOT_SECONDARY**
Font to use for time axis secondary annotations [default is
:doc:`theme dependent <theme-settings>`] Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**FONT_HEADING**
Font to use when plotting headings above subplots [default is
:doc:`theme dependent <theme-settings>`]. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**FONT_LABEL**
Font to use when plotting labels below axes [default is :doc:`theme dependent
<theme-settings>`]. Choose **auto** for :ref:`automatic scaling with plot
size <auto-scaling>`.
**FONT_LOGO**
Font to use for text plotted as part of the GMT time logo. **Note**: Since the
time logo has a fixed height the font size for the time stamp is 8p and for the
optional label it is 7p. Hence, changing this font only affects the font style
and color but not its size.
**FONT_SUBTITLE**
Font to use when plotting titles over graphs that involve a subtitle
[default is :doc:`theme dependent <theme-settings>`]. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**FONT_TAG**
Font to use for subplot panel tags such as a), ii)
[default is :doc:`theme dependent <theme-settings>`]. Choose **auto**
for :ref:`automatic scaling with plot size <auto-scaling>`.
**FONT_TITLE**
Font to use when plotting titles over graphs [default is :doc:`theme dependent
<theme-settings>`]. Choose **auto** for :ref:`automatic scaling with plot
size <auto-scaling>`.
.. glossary::
**FORMAT_CLOCK_IN**
Formatting template that indicates how a clock string is formatted.
This template is then used to guide the reading of clock strings in data fields.
For 12-hour clocks, append **am**, **AM**, **a.m.**, or **A.M.** (GMT will replace a\|A with p\|P for pm).
As examples, try hh:mm, hh:mm:ssAM, hh:mm:ss.xxxx etc. [default is **hh:mm:ss**].
**FORMAT_CLOCK_MAP**
Formatting template that indicates how an output clock string is to
be plotted. This template is then used to guide the formatting of
clock strings in plot annotations. See :term:`FORMAT_CLOCK_OUT` for
details [default is **hh:mm:ss**].
**FORMAT_CLOCK_OUT**
See :term:`FORMAT_CLOCK_IN`.
In addition, for output we can also start the template with a leading hyphen (**-**).
Then each integer item (y,m,d) will be printed without leading zeros (default uses fixed width formats).
If the format is simply **-** then no clock is output and the ISO T divider between date and clock is omitted.
To use a floating point format for the smallest unit (e.g., seconds), append **.xxx**, where the number of x indicates the desired precision.
If no floating point is indicated then the smallest specified unit will be rounded off to nearest integer.
**Note**: When high-precision time-series are written to ASCII output the default format may not be adequate.
Many modules automatically handle this by extending the format, but you should be alert of unusual situations where data may appear truncated to nearest second.
**FORMAT_DATE_IN**
Formatting template that indicates how an input date string is
formatted. This template is then used to guide the reading of date
strings in data fields. You may specify either Gregorian calendar
format or ISO week calendar format. Gregorian calendar: Use any
combination of **yyyy** (or **yy** for 2-digit years; if so see
:term:`TIME_Y2K_OFFSET_YEAR`), **mm** (or **o** for abbreviated month
name in the current time language), and **dd**, with or without delimiters.
For day-of-year data, use **jjj** instead of **mm** and/or **dd**. Examples
can be ddmmyyyy, yy-mm-dd, dd-o-yyyy, yyyy/dd/mm, yyyy-jjj, etc. ISO
Calendar: Expected template is **yyyy[-]W[-]ww[-]d**, where ww is ISO
week and d is ISO week day. Either template must be consistent,
e.g., you cannot specify months if you do not specify years.
Examples are yyyyWwwd, yyyy-Www, etc. [default is **yyyy-mm-dd**].
**FORMAT_DATE_MAP**
Formatting template that indicates how an output date string is to
be plotted. This template is then used to guide the plotting of date
strings in data fields. See :term:`FORMAT_DATE_OUT` for details. In
addition, you may use a single **o** instead of **mm** (to plot month name)
and **u** instead of W[-]ww to plot "Week ##". Both of these text
strings will be affected by the :term:`GMT_LANGUAGE`,
:term:`FORMAT_TIME_PRIMARY_MAP` and :term:`FORMAT_TIME_SECONDARY_MAP`
setting [default is **yyyy-mm-dd**].
**FORMAT_DATE_OUT**
Formatting template that indicates how an output date string is to
be formatted. This template is then used to guide the writing of
date strings in data fields. You may specify either Gregorian
calendar format or ISO week calendar format. Gregorian calendar: Use
any combination of **yyyy** (or **yy** for 2-digit years; if so see
:term:`TIME_Y2K_OFFSET_YEAR`), **mm** (or **o** for abbreviated month name
in the current time language), and **dd**, with or without delimiters. For
day-of-year data, use **jjj** instead of mm and/or dd. As examples, try
yy/mm/dd, yyyy=jjj, dd-o-yyyy, dd-mm-yy, yy-mm, etc. ISO Calendar:
Expected template is **yyyy[-]W[-]ww[-]d**, where ww is ISO week and d
is ISO week day. Either template must be consistent, e.g., you
cannot specify months if you do not specify years. As examples, try
yyyyWww, yy-W-ww-d, etc. If your template starts with a leading
hyphen (**-**) then each integer item (y,m,d) will be printed without
leading zeros (default uses fixed width formats) [default is **yyyy-mm-dd**].
If the format is simply **-** then no date is output and the ISO T divider
between date and clock is omitted.
**FORMAT_GEO_MAP**
Formatting template that indicates how an output geographical
coordinate is to be plotted. This template is then used to guide the
plotting of geographical coordinates in data fields. See
:term:`FORMAT_GEO_OUT` for details. In addition, you can append **A**
which plots the absolute value of the coordinate. Not all items may be
plotted as this depends on the annotation interval [default is
:doc:`theme dependent <theme-settings>`].
**FORMAT_GEO_OUT**
Formatting template that indicates how an output geographical
coordinate is to be formatted. This template is then used to guide
the writing of geographical coordinates in data fields. The template
is in general of the form **[±]D[DD]** or **[±]ddd[:mm[:ss]][.xxx]** [default is **D**].
By default, longitudes will be reported in the range [-180,180]. The
various terms have the following purpose:
======== =================================================================
Term Purpose
======== =================================================================
**D** Use :term:`FORMAT_FLOAT_OUT` for floating point degrees [default]
**+D** Output longitude in the range [0,360]
**-D** Output longitude in the range [-360,0]
**DDD** Fixed format integer degrees (3 digits for longitude, 2 digits for latitude)
**ddd** Integer degrees
**:** Delimiter used (this will translate to degree, minute, seconds symbols on maps)
**mm** Fixed format integer arc minutes (2 digits)
**ss** Fixed format integer arc seconds (2 digits)
**.xxx** Floating fraction of previous integer field, fixed width
**F** Encode sign using WESN suffix
**G** Same as **F** but with a leading space before suffix
======== =================================================================
**Note**: With :term:`FORMAT_GEO_MAP`, **F** and **G** may also be used as a prefix.
**FORMAT_FLOAT_MAP**
Format (C language printf syntax, see :term:`FORMAT_FLOAT_OUT`) to be used when plotting double
precision floating point numbers along plot frames and contours [default is **%.12g**].
For geographic coordinates, see :term:`FORMAT_GEO_MAP`.
**FORMAT_FLOAT_OUT**
Format (C language `printf <https://en.wikipedia.org/wiki/Printf_format_string>`_ syntax)
to be used when printing double precision floating point numbers to output files [default is **%.12g**].
For geographic coordinates, see :term:`FORMAT_GEO_OUT`.
To give some columns a separate format,
supply one or more comma-separated *cols*:*format* specifications,
where *cols* can be specific columns (e.g., 5 for 6th since 0 is the first)
or a range of columns (e.g., 3-7).
The last specification without column information will override the format for all other columns.
Alternatively, you can list N space-separated formats and these apply to the first N columns.
The printf syntax is ``%[minimum width].[precision]type``,
where **type** may be **f**, **e**, **E**, **g** or **G**.
The default is ``%.12g``, i.e. no minimum width and 12 digit precision.
See table below for examples. Input is π (3.14159265359).
====== =============
Format Output
====== =============
%.12g 3.14159265359
%.2f 3.14
%8.4f __3.1416
%08.2f 00003.14
%.5f 3.14159
====== =============
**FORMAT_TIME_MAP**
Sets both :term:`FORMAT_TIME_PRIMARY_MAP` and :term:`FORMAT_TIME_SECONDARY_MAP`
to the value specified. This setting is not included in the **gmt.conf** file.
**FORMAT_TIME_PRIMARY_MAP**
Controls how primary month-, week-, and weekday-names are formatted.
Choose among **full**, **abbreviated**, and **character**. If the
leading **f**, **a**, or **c** are replaced with **F**, **A**, and
**C** the entire annotation will be in upper case [default is **full**].
**FORMAT_TIME_SECONDARY_MAP**
Controls how secondary month-, week-, and weekday-names are
formatted. Choose among **full**, **abbreviated**, and
**character**. If the leading **f**, **a**, or **c** are replaced
with **F**, **A**, and **C** the entire annotation will be in upper case
[default is **full**].
**FORMAT_TIME_STAMP**
Defines the format of the time information in the UNIX time stamp.
This format is parsed by the C function **strftime**, so that
virtually any text can be used (even not containing any time
information) [default is **%Y %b %d %H:%M:%S**].
.. glossary::
**GMT_COMPATIBILITY**
Determines if the current GMT version should be able to parse command-line
options for a prior major release. Specify the major release version number,
e.g., 4-6. If 4 is set we will parse obsolete GMT 4 options and issue warnings;
if 5 is set then parsing GMT 4 only syntax will result in errors [default is 4];
likewise for 6: obsolete syntax from early GMT 5 will be considered errors.
**GMT_DATA_SERVER**
Name (or URL) of a GMT data server [default is **oceania**]. Please set
to the data server closest to your location for faster data download. See
`Data Server Mirrors <https://www.generic-mapping-tools.org/mirrors/#data-server-mirrors>`_
for a list of the currently available mirrors.
**GMT_DATA_SERVER_LIMIT**
Upper limit on the size of remote file to download [default is **unlimited**].
Give the maximum file size in bytes, or append **k**, **m**, or **g** for
kilo-, mega-, or giga-bytes.
**GMT_DATA_UPDATE_INTERVAL**
Specifies how often we update the local catalog of data available on
the remote server and pruning expired data sets [default is **1d**].
Allowable time units are **d** (days), **w** (week), **o** (month,
here 30 days). To turn off periodic updates entirely, specify interval
as **off**, **never**, **infinity**, or just **0**.
**GMT_EXPORT_TYPE**
This setting is only used by external interfaces and controls the data
type used for table entries. Choose from **double**, **single**,
**[u]long**, **[u]int**, **[u]short**, and **[u]char** [default is **double**].
**GMT_EXTRAPOLATE_VAL**
Determines what to do if extrapolating beyond the data domain. Choose
among **NaN**, **extrap** or **extrapval**,\ *value*. In the first case
return NaN for any element of x that is outside range. Second case lets
the selected algorithm compute the extrapolation values. Third case sets
the extrapolation values to the constant value passed in *value* (this
value must of course be numeric) [default is **NaN**].
**GMT_CUSTOM_LIBS**
Comma-separated list of GMT-compliant shared libraries that extend
the capability of GMT with additional custom modules [default is **none**].
Alternatively, provide a directory name, that MUST end with a slash (or
back slash), to use all shared libraries in that directory. On Windows,
if the dir name is made up only of a single slash ('/') search inside a
subdirectory called **gmt_plugins** of the directory that contains the
**gmt** executable. See the API documentation for how to build your own
shared modules.
**GMT_FFT**
Determines which Fast Fourier Transform (FFT) library should be used among
those that have been configured during installation. Choose from
**auto** (pick the most suitable for the task among available
algorithms), **fftw**\ [,\ *planner_flag*] (The Fastest Fourier
Transform in the West), **accelerate** (Use the Accelerate Framework
under macOS; Note, that the number of samples to be processed must be
a base 2 exponent), **kiss**, (Kiss FFT), **brenner** Brenner Legacy
FFT [default is **auto**].
FFTW can "learn" how to optimally compute Fourier transforms on the
current hardware and OS by computing several FFTs and measuring
their execution time. This so gained "Wisdom" will be stored in and
reloaded from the file fftw_wisdom_<hostname> in **$GMT_USERDIR** or, if
**$GMT_USERDIR** is not writable, in the current directory. To use this
feature append *planner_flag*, which can be one of *measure*,
*patient*, *exhaustive* and *estimate* which pick a (probably
sub-optimal) plan quickly [default is *estimate*]. See FFTW reference for
details. **Note**: If you need a single transform of a
given size only, the one-time cost of the smart planner becomes
significant. In that case, stick to the default planner, *estimate*,
based on heuristics.
**GMT_GRAPHICS_DPU**
Default target dots-per-unit for images when a remote gridded data
set is requested without specifying a resolution (e.g., @earth_relief).
Append "i" to indicate the DPU is dots-per-inches and "c" for dots-per-cm.
[default is 300i].
**GMT_GRAPHICS_FORMAT**
Default graphics format in modern mode [default is **pdf**].
**GMT_HISTORY**
Passes the history of past common command options via the
gmt.history file. The different values for this setting are:
**true**, **readonly**, **false**, to either read and write to the
gmt.history file, only read, or not use the file at all [default is **true**].
**GMT_INTERPOLANT**
Determines if linear (**linear**), `Akima's <https://en.wikipedia.org/wiki/Akima_spline>`_
spline (**akima**), natural cubic spline (**cubic**) or no interpolation (**none**)
should be used for 1-D interpolations in various programs [default is **akima**].
**GMT_LANGUAGE**
Language to use when plotting calendar and map items such as months and
days, map annotations and cardinal points. Select from:
.. hlist::
:columns: 3
- *CN1*: Simplified Chinese
- *CN2*: Traditional Chinese
- *DE*: German
- *DK*: Danish
- *EH*: Basque
- *ES*: Spanish
- *FI*: Finnish
- *FR*: French
- *GR*: Greek
- *HI*: Hawaiian
- *HU*: Hungarian
- *IE*: Irish
- *IL*: Hebrew
- *IS*: Icelandic
- *IT*: Italian
- *JP*: Japanese
- *KR*: Korean
- *NL*: Dutch
- *NO*: Norwegian
- *PL*: Polish
- *PT*: Portuguese
- *RU*: Russian
- *SE*: Swedish
- *SG*: Scottish Gaelic
- *TO*: Tongan
- *TR*: Turkish
- *UK*: British English
- *US*: US English
If your language is not supported, please examine the
**$GMT_SHAREDIR**/localization/gmt_us.locale file and make a similar file. Please
submit it to the GMT Developers for official inclusion. Custom
language files can be placed in directories **$GMT_SHAREDIR**/localization
or ~/.gmt. **Note**: Some of these languages may require you to also
change the :term:`PS_CHAR_ENCODING` setting.
**GMT_MAX_CORES**
Sets the upper limit on the number of cores any multi-threaded module might
use (whether **-x** is selected or not) [default is **0** (i.e., unlimited)].
**GMT_THEME**
Override GMT default settings with those of the selected theme. Choose from
*classic* [Default for classic mode], *modern* [Default for modern mode],
and *minimal*. You can also create and use your own themes by compiling
files of desired settings and place them in your GMT user themes directory
(usually ~/.gmt/themes) and name them *theme*.conf. See the
:doc:`theme settings table<theme-settings>` for parameters associated with
each theme.
**GMT_TRIANGULATE**
Determines if we use the **Watson** or **Shewchuk**
algorithm (if configured during installation) for triangulation.
Note that Shewchuk is required for operations involving Voronoi
constructions [default is **Shewchuk**].
**GMT_VERBOSE**
(**-V**) Determines the level of verbosity used by GMT
programs. Choose among 7 levels; each level adds to the verbosity of
the lower levels: **q**\ uiet, **e**\ rrors, **w**\ arnings,
**t**\ imings (for slow algorithms only), **i**\ nformation,
**c**\ ompatibility warnings, and **d**\ ebugging messages [default is **w**].
.. glossary::
**IO_COL_SEPARATOR**
This setting determines what character will separate ASCII *output*
data columns written by GMT. Choose from **tab**, **space**, **comma**,
**semicolon** and **none** [default is **tab**]. You may also just give
any character or string (e.g., "--|--"). **Note**: When reading input
data GMT automatically skips white-space, commas, and semi-colons; you
cannot select an individual input column separator.
**IO_FIRST_HEADER**
This setting determines if the first segment header is written when
there is only a single segment (for multiple segment it must be written).
By default, such single-segment headers are only written if the header
has contents. Choose from **always**, **never**, or **maybe** [default is **maybe**].
**IO_GRIDFILE_FORMAT**
Default file format for grids, with optional scale, offset and
invalid value, written as *ff*\ [**+s**\ *scale*][**+o**\ *offset*][**+n**\ *invalid*].
The 2-letter format indicator can be one of [**abcegnrs**][**bsifd**]. See
:doc:`grdconvert` and Section :ref:`grid-file-format` of the GMT Technical
Reference for more information. You may the scale as **a**
for auto-adjusting the scale and/or offset of packed integer grids
(=\ *ID*\ **+s**\ *a* is a shorthand for =\ *ID*\ **+s**\ *a*\ **+o**\ *a*).
When *invalid* is omitted the appropriate value for the given format is used
(NaN or largest negative) [default is **nf**].
**IO_GRIDFILE_SHORTHAND**
If **true**, all grid file names are examined to see if they use the
file extension shorthand discussed in Section :ref:`grid-file-format` of
the GMT Technical Reference. If **false**, no filename
expansion is done [default is **false**].
**IO_HEADER**
(**-h**) Specifies whether input/output ASCII files have header record(s)
or not [default is **false**].
**IO_HEADER_MARKER**
Give a string from which any character will indicate a header record in
an incoming ASCII data table if found in the first position [default is **#%!;"'**].
If another marker should be used for output than the first character in
the list, then append a single character for the output header record
marker. The two sets must be separated by a comma. **Note**: A maximum
of 7 input markers can be specified.
**IO_LONLAT_TOGGLE**
(**-:**) Set if the first two columns of input and output files
contain (*latitude,longitude*) or (**y, x**) rather than the expected
(longitude,latitude) or (*x, y*). false means we have (*x, y*) both on
input and output. **true** means both input and output should be (**y, x**).
**IN** means only input has (**y, x**), while **OUT** means only output should
be (**y, x**) [default is **false**].
**IO_N_HEADER_RECS**
Specifies how many header records to expect if **-h** is used [default is **0**].
**Note**: This will skip the specified number of records regardless of
what they are. Since any records starting with **#** is automatically
considered a header you will only specify a non-zero number in order
to skip headers that do not conform to that convention.
**IO_NAN_RECORDS**
Determines what happens when input records containing NaNs for *x*
or *y* (and in some cases *z*) are read. This may happen, for instance,
when there is text or other junk present instead of data coordinates, and
the conversion to a data value fails and yields a NaN. Choose between
**skip**, which will report how many bad records were skipped, and **pass**,
which will quietly pass these records on to the calling programs [default
is **pass**]. For most programs this will result in output records with
NaNs as well, but some will interpret these NaN records to indicate
gaps in a series; programs may then use that information to detect
segmentation (if applicable).
**IO_NC4_CHUNK_SIZE**
Sets the default chunk size for the vertical (**lat**, **y**) and
horizontal (**lon**, **x**) dimensions of
the **z** variable. Very large chunk sizes and sizes smaller than
128 should be avoided because they can lead to unexpectedly bad
performance. Note that a chunk of a single precision floating point
variable of size 2896 x 2896 completely fills the chunk cache of
32 Mb. Specify the chunk size for each dimension separated by a
comma, or **a**\ uto for optimally chosen chunk sizes in the range
[128,256). Setting :term:`IO_NC4_CHUNK_SIZE` will produce netCDF version 4
files, which can only be read with the netCDF 4 library, unless all
dimensions are less than 128 or **c**\ lassic is specified for
classic netCDF [default is **auto**]
**IO_NC4_DEFLATION_LEVEL**
Sets the compression level for netCDF4 files upon output. Values
allowed are integers from **0** (no compression) to **9** (maximum
compression). Enabling a low compression level can dramatically
improve performance and reduce the size of certain data. While
higher compression levels further reduce the data size, they do so
at the cost of extra processing time. This parameter does not
apply to classic netCDF files [default is **3**].
**IO_SEGMENT_BINARY**
Determines how binary data records with all values set to NaN are
interpreted. Such records are considered to be encoded segment
headers in binary files provided the number of columns equals or
exceeds the current setting of IO_SEGMENT_BINARY [default is **2**].
Specify **0** or **off** to deactivate the segment header determination.
**IO_SEGMENT_MARKER**
This holds the character we expect to indicate a segment header in
an incoming ASCII data or text table [default is **>**]. If this marker
should be different for output then append another character for the output
segment marker. The two characters must be separated by a **comma**. Two
marker characters have special meaning: **B** means "blank line" and
will treat blank lines as initiating a new segment, whereas **N** means
"NaN record" and will treat records with all NaNs as initiating a
new segment. If you choose **B** or **N** for the output marker then the
normal GMT segment header is replaced by a blank or NaN record,
respectively, and no segment header information is written. To use **B**
or **N** as regular segment markers you must escape them with a leading
backslash.
.. glossary::
**MAP_ANNOT_MIN_ANGLE**
If the angle between the map boundary and the annotation baseline is
less than this minimum value (in degrees), the annotation is not
plotted (this may occur for certain oblique projections). Give a
value in the range [0,90] [default is **20**].
**MAP_ANNOT_MIN_SPACING**
If an annotation would be plotted less than this minimum distance
from its closest neighbor, the annotation is not plotted (this may
occur for certain oblique or polar projections) [default is
:doc:`theme dependent <theme-settings>`]. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_ANNOT_OBLIQUE**
This setting applies to "oblique" projections, which in this context
means maps whose boundary is a rectangle not specified by meridians
and parallels. We expect a comma-separated list of up to seven
keywords [default is **anywhere**]:
============== ============================================================================================================
Keyword Meaning
============== ============================================================================================================
separate Annotate longitudes on lower and upper boundaries only, and latitudes on the left and right boundaries only
anywhere Annotations will occur wherever an imaginary gridline crosses the map boundaries
lon_horizontal Longitude annotations will be plotted horizontally
lat_horizontal Latitude annotations will be plotted horizontally
tick_extend Extend tick-marks so distance from tip of the oblique tick to map frame equals specified tick length
tick_normal Draw tick-marks normal to the border regardless of gridline angle
lat_parallel Latitude annotations will be plotted parallel to the border
============== ============================================================================================================
**MAP_ANNOT_OFFSET**
Sets both :term:`MAP_ANNOT_OFFSET_PRIMARY` and
:term:`MAP_ANNOT_OFFSET_SECONDARY` to the value specified.
This setting is not included in the **gmt.conf** file.
**MAP_ANNOT_OFFSET_PRIMARY**
Distance from end of tick-mark to start of annotation [default is
:doc:`theme dependent <theme-settings>`]. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_ANNOT_OFFSET_SECONDARY**
Distance from base of primary annotation to the top of the secondary
annotation (Only applies to time axes with both primary and secondary
annotations) [default is :doc:`theme dependent <theme-settings>`]. Choose
**auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_ANNOT_ORTHO**
Determines which axes will get their annotations (for Cartesian
projections) plotted orthogonally to the axes. Combine any **w**, **e**,
**s**, **n**, **z** (uppercase allowed as well) [default is **we**] (if
nothing specified). Note that this setting can be overridden via the
**+a** modifier in **-B**.
**MAP_DEFAULT_PEN**
Sets the default of all pens related to **-W** options. Prepend
**+** to overrule the color of the parameters
:term:`MAP_GRID_PEN_PRIMARY`, :term:`MAP_GRID_PEN_SECONDARY`,
:term:`MAP_FRAME_PEN`, :term:`MAP_TICK_PEN_PRIMARY`, and
:term:`MAP_TICK_PEN_SECONDARY` by the color of :term:`MAP_DEFAULT_PEN`
[default is **0.25p,black**].
**MAP_DEGREE_SYMBOL**
Determines what symbol is used to plot the degree symbol on geographic
map annotations. Choose between **ring**, **degree**, **colon**, or
**none** [default is **degree**].
**MAP_EMBELLISHMENT_MODE**
Determines if map embellishments like directional or magnetic compasses,
map scales or vertical data scales should have attributes that scale with
the size of the feature (**auto**) or use the settings as is (**manual**).
**MAP_FRAME_AXES**
Sets which axes to draw and annotate. Combine any uppercase **W**,
**E**, **S**, **N**, **Z** to draw and annotate west, east, south,
north and/or vertical (perspective view only) axis. Use lower case
to draw the axis only, but not annotate. To *just* draw an axis
without annotation and ticks you can use the **l**\ (eft), **r**\ (ight),
**b**\ (ottom), **t**\ (op) and (for 3-D) **u**\ (p) codes. Add an
optional **+b** to draw a cube of axes in perspective view. Choose
**auto** for :ref:`automatic selection <auto-scaling>` [default is
:doc:`theme dependent <theme-settings>`].
**MAP_FRAME_PEN**
Pen attributes used to draw plain map frame [default is :doc:`theme dependent
<theme-settings>`]. Choose **auto** for :ref:`automatic scaling with plot size
<auto-scaling>`.
**MAP_FRAME_PERCENT**
Percentage of the fancy frame width to use for the internal checkerboard
frame lines [default is **100**].
**MAP_FRAME_TYPE**
Choose between **inside**, **plain** and **fancy** (thick boundary,
alternating black/white frame; append **-rounded** for rounded corners)
[default is :doc:`theme dependent <theme-settings>`]. For some map
projections (e.g., Oblique Mercator), plain is the only option even if
fancy is set as default. In general, fancy only applies to situations
where the projected x and y directions parallel the longitude and
latitude directions (e.g., rectangular projections, polar projections).
For situations where all boundary ticks and annotations must be inside
the maps (e.g., for preparing GeoTIFF output), chose **inside**. Finally,
for Cartesian plots you can also choose **graph**\ , which adds a vector
to the end of each axis. This works best when you reduce the number of
axes plotted to one per dimension. By default, the vector tip extends
the length of each axis by 7.5%. Alternatively, append ,\ *length*,
where the optional *unit* may be **%** (then *length* is the alternate
extension in percent) or one of **c**, **i**, or **p** (then *length*
is the absolute extension of the axis to the start of the vector base
instead). The vector stem is set to match :term:`MAP_FRAME_WIDTH`, while
the vector head length and width are 10 and 5 times this width,
respectively. You may control its shape via :term:`MAP_VECTOR_SHAPE`.
The graph vectors are plotted as normal boundary axes. Use **graph-origin**
to shift the **W** and **S** axes so they intersect at the user data
(0, 0) origin instead. In this mode, only the **W** and **S** axes can be
selected (or **w**, **s**, **l**, and **b** too); the **E** and **N** (and
**e**, **n**, **r** and **t**) will be ignored. **Note**: Annotations
at any axes intersections will be suppressed. To select another intersection point
than the data origin you may append **+o**\ *xorig*/*yorig* or the short-cut
**+oc** to center the axes on the current data domain [0/0].
.. toggle::
Here is an example showing the appearance of different **MAP_FRAME_TYPE** settings.
.. literalinclude:: /_verbatim/GMT_map_frame_type.txt
.. figure:: /_images/GMT_map_frame_type.*
:width: 100%
:align: center
Appearance of different **MAP_FRAME_TYPE** settings
**MAP_FRAME_WIDTH**
Width (> 0) of map borders for fancy map frame [default is :doc:`theme dependent
<theme-settings>`]. **Note**: For fancy frames, :term:`MAP_FRAME_PEN`
is automatically set to 0.1 times the :term:`MAP_FRAME_WIDTH` setting.
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_GRID_CROSS_SIZE**
Sets both :term:`MAP_GRID_CROSS_SIZE_PRIMARY` and :term:`MAP_GRID_CROSS_SIZE_SECONDARY`
to the value specified. This setting is not included in the **gmt.conf** file.
**MAP_GRID_CROSS_SIZE_PRIMARY**
Size of grid cross at primary lon-lat intersections. **0** means draw
continuous gridlines instead. A nonzero size will draw a symmetric grid
cross. Signed sizes have special meaning and imply grid line ticks that
embellish an already drawn set of gridlines: A negative size will only
draw ticks away from Equator and Greenwich, while a positive size will
draw symmetric ticks [default is **0p**].
**MAP_GRID_CROSS_SIZE_SECONDARY**
Size of grid cross at secondary lon-lat intersections.
See :term:`MAP_GRID_CROSS_SIZE_PRIMARY` for details.
[default is **0p**].
**MAP_GRID_PEN**
Sets both :term:`MAP_GRID_PEN_PRIMARY` and :term:`MAP_GRID_PEN_SECONDARY` to
the value specified. This setting is not included in the **gmt.conf** file.
**MAP_GRID_PEN_PRIMARY**
Pen attributes used to draw primary grid lines in dpi units or
points (append **p**) [default is :doc:`theme dependent <theme-settings>`].
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_GRID_PEN_SECONDARY**
Pen attributes used to draw secondary grid lines in dpi units or
points (append **p**) [default is :doc:`theme dependent <theme-settings>`].
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_HEADING_OFFSET**
Distance from top of subplot panel titles to the base of the heading
[default is :doc:`theme dependent <theme-settings>`]. Choose **auto** for
:ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_LABEL_MODE**
Determines from where the label offset is measured: Choose **annot**
to mean the distance from the end of the annotation or **axis**
to mean the distance from the axis. To set separate modes for the
*x* and *y* axes, separate modes by a slash [default is **annot/annot**]. Choose
**axis** if you need to align multiple axes labels across many rows or columns.
**MAP_LABEL_OFFSET**
Distance from base of axis annotations to the top of the axis label
[default is :doc:`theme dependent <theme-settings>`]. Choose **auto**
for :ref:`automatic scaling with plot size <auto-scaling>`. To
set different offsets for the *x* and *y* axes, separate distances
by a slash (e.g., **8p/12p** for 8p offset for the x-axis and 12p
offset for the y-axis)
**MAP_LINE_STEP**
Determines the maximum length (> 0) of individual straight
line-segments when drawing arcuate lines [default is **0.75p**]
**MAP_LOGO**
(**-U**) Specifies if a GMT logo with system timestamp should be
plotted at the lower left corner of the plot [default is **false**].
**MAP_LOGO_POS**
(**-U**) Sets the justification and the position of the
logo/timestamp box relative to the current plot's lower left corner
(i.e., map origin) [default is **BL/-54p/-54p**].
**MAP_ORIGIN_X**
(**-X**) Sets the x-coordinate of the origin on the paper for a
new plot [default is **72p**]. For an overlay, the default offset is **0**.
**MAP_ORIGIN_Y**
(**-Y**) Sets the y-coordinate of the origin on the paper for a
new plot [default is **72p**]. For an overlay, the default offset is **0**.
**MAP_POLAR_CAP**
Controls the appearance of gridlines near the poles for all
azimuthal projections and a few others in which the geographic poles
are plotted as points (Lambert Conic, Oblique and Transverse Mercator, UTM, Hammer, Mollweide,
Sinusoidal and van der Grinten). Specify either **none** (in which case
there is no special handling) or *pc_lat*/*pc_dlon*. In that case, normal
gridlines are only drawn between the latitudes -*pc_lat*/+\ *pc_lat*, and
above those latitudes the gridlines are spaced at the (presumably coarser)
*pc_dlon* interval; the two domains are separated by a small circle drawn
at the *pc_lat* latitude. Alternatively, give **auto** to determine a
*pc_lat* suitable for your region [default is
:doc:`theme dependent <theme-settings>`]. Note for r-theta (polar)
projection where r = 0 is at the center of the plot the meaning of the
cap is reversed, i.e., *85/90* will draw a r = 5 radius circle at the
center of the map with less frequent radial lines there.
**MAP_SCALE_HEIGHT**
Sets the height (> 0) on the map of the map scale bars drawn by
various programs [default is **5p**].
**MAP_SYMBOL_PEN_SCALE**
Used to convert non-fillable (**x**, **y**, **+** and **-**) symbol sizes
to the width of the pen used to stroke these symbols. Give a factor in the
0-1 range (e.g., 0.18) or specify a percentage (e.g., 10%) [15%]. **Note**:
If set to 0 then no such conversion takes place and pen settings must rely on
**-W** or module defaults.
**MAP_TICK_LENGTH**
Sets both :term:`MAP_TICK_LENGTH_PRIMARY` and :term:`MAP_TICK_LENGTH_SECONDARY`
to the value specified. This setting is not included in the **gmt.conf** file.
**MAP_TICK_LENGTH_PRIMARY**
The length of a primary major/minor tick-marks [default is :doc:`theme dependent
<theme-settings>`]. If only the first value is set, the second
is assumed to be 50% of the first. Choose **auto** for :ref:`automatic
scaling with plot size <auto-scaling>`.
**MAP_TICK_LENGTH_SECONDARY**
The length of a secondary major/minor tick-marks [default is :doc:`theme dependent
<theme-settings>`]. If only the first value is set, the second is assumed
to be 25% of the first. Choose **auto** for :ref:`automatic scaling with
plot size <auto-scaling>`.
**MAP_TICK_PEN**
Sets both :term:`MAP_TICK_PEN_PRIMARY` and :term:`MAP_TICK_PEN_SECONDARY`
to the value specified. This setting is not included in the **gmt.conf** file.
**MAP_TICK_PEN_PRIMARY**
Pen attributes to be used for primary tick-marks in dpi units or
points (append **p**) [default is :doc:`theme dependent <theme-settings>`].
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_TICK_PEN_SECONDARY**
Pen attributes to be used for secondary tick-marks in dpi units or
points (append **p**) [default is :doc:`theme dependent <theme-settings>`].
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_TITLE_OFFSET**
Distance from top of axis annotations (or axis label, if present) to
base of plot title [default is :doc:`theme dependent <theme-settings>`].
Choose **auto** for :ref:`automatic scaling with plot size <auto-scaling>`.
**MAP_VECTOR_SHAPE**
Determines the shape of the head of a vector. Normally (i.e., for
vector_shape = **0**), the head will be triangular, but can be changed
to an arrow (**1**) or an open V (**2**). Intermediate settings give
something in between. Negative values (up to **-2**) are allowed as well
[default is :doc:`theme dependent <theme-settings>`].
.. glossary::
**PROJ_AUX_LATITUDE**
Only applies when geodesics are approximated by great circle distances on
an equivalent sphere. Select from **authalic**, **geocentric**,
**conformal**, **meridional**, **parametric**, or **none** (i.e., geodetic)
[default is **authalic**]. When not none we convert any latitude used in
the great circle calculation to the chosen auxiliary latitude before
doing the distance calculation. See also :term:`PROJ_MEAN_RADIUS`.
**PROJ_ELLIPSOID**
The name of the ellipsoid used for the map projections [WGS-84]. Choose among:
- *Airy*: Applies to Great Britain (1830)
- *Airy-Ireland*: Applies to Ireland in 1965 (1830)
- *Andrae*: Applies to Denmark and Iceland (1876)
- *APL4.9*: Appl. Physics (1965)
- *ATS77*: Average Terrestrial System, Canada Maritime provinces (1977)
- *Australian*: Applies to Australia (1965)
- *Bessel*: Applies to Central Europe, Chile, Indonesia (1841)
- *Bessel-Namibia*: Same as Bessel-Schwazeck (1841)
- *Bessel-NGO1948*: Modified Bessel for NGO 1948 (1841)
- *Bessel-Schwazeck*: Applies to Namibia (1841)
- *Clarke-1858*: Clarke's early ellipsoid (1858)
- *Clarke-1866*: Applies to North America, the Philippines (1866)
- *Clarke-1866-Michigan*: Modified Clarke-1866 for Michigan (1866)
- *Clarke-1880*: Applies to most of Africa, France (1880)
- *Clarke-1880-Arc1950*: Modified Clarke-1880 for Arc 1950 (1880)
- *Clarke-1880-IGN*: Modified Clarke-1880 for IGN (1880)
- *Clarke-1880-Jamaica*: Modified Clarke-1880 for Jamaica (1880)
- *Clarke-1880-Merchich*: Modified Clarke-1880 for Merchich (1880)
- *Clarke-1880-Palestine*: Modified Clarke-1880 for Palestine (1880)
- *CPM*: Comm. des Poids et Mesures, France (1799)
- *Delambre*: Applies to Belgium (1810)
- *Engelis*: Goddard Earth Models (1985)
- *Everest-1830*: India, Burma, Pakistan, Afghanistan, Thailand (1830)
- *Everest-1830-Kalianpur*: Modified Everest for Kalianpur (1956) (1830)
- *Everest-1830-Kertau*: Modified Everest for Kertau, Malaysia & Singapore (1830)
- *Everest-1830-Pakistan*: Modified Everest for Pakistan (1830)
- *Everest-1830-Timbalai*: Modified Everest for Timbalai, Sabah Sarawak (1830)
- *Fischer-1960*: Used by NASA for Mercury program (1960)
- *Fischer-1960-SouthAsia*: Same as Modified-Fischer-1960 (1960)
- *Fischer-1968*: Used by NASA for Mercury program (1968)
- *FlatEarth*: As Sphere, but implies fast "Flat Earth" distance calculations (1984)
- *GRS-67*: International Geodetic Reference System (1967)
- *GRS-80*: International Geodetic Reference System (1980)
- *Hayford-1909*: Same as the International 1924 (1909)
- *Helmert-1906*: Applies to Egypt (1906)
- *Hough*: Applies to the Marshall Islands (1960)
- *Hughes-1980*: Hughes Aircraft Company for DMSP SSM/I grid products (1980)
- *IAG-75*: International Association of Geodesy (1975)
- *Indonesian*: Applies to Indonesia (1974)
- *International-1924*: Worldwide use (1924)
- *International-1967*: Worldwide use (1967)
- *Kaula*: From satellite tracking (1961)
- *Krassovsky*: Used in the (now former) Soviet Union (1940)
- *Lerch*: For geoid modeling (1979)
- *Maupertius*: Really old ellipsoid used in France (1738)
- *Mercury-1960*: Same as Fischer-1960 (1960)
- *MERIT-83*: United States Naval Observatory (1983)
- *Modified-Airy*: Same as Airy-Ireland (1830)
- *Modified-Fischer-1960*: Applies to Singapore (1960)
- *Modified-Mercury-1968*: Same as Fischer-1968 (1968)
- *NWL-10D*: Naval Weapons Lab (Same as WGS-72) (1972)
- *NWL-9D*: Naval Weapons Lab (Same as WGS-66) (1966)
- *OSU86F*: Ohio State University (1986)
- *OSU91A*: Ohio State University (1991)
- *Plessis*: Old ellipsoid used in France (1817)
- *SGS-85*: Soviet Geodetic System (1985)
- *South-American*: Applies to South America (1969)
- *Sphere*: The mean radius in WGS-84 (for spherical/plate tectonics applications) (1984)
- *Struve*: Friedrich Georg Wilhelm Struve (1860)
- *TOPEX*: Used commonly for altimetry (1990)
- *Walbeck*: First least squares solution by Finnish astronomer (1819)
- *War-Office*: Developed by G. T. McCaw (1926)
- *WGS-60*: World Geodetic System (1960)
- *WGS-66*: World Geodetic System (1966)
- *WGS-72*: World Geodetic System (1972)
- *WGS-84*: World Geodetic System [Default] (1984)
- *Web-Mercator*: Spherical Mercator with WGS-84 radius (1984)
- *Moon*: Moon (IAU2000) (2000)
- *Mercury*: Mercury (IAU2000) (2000)
- *Venus*: Venus (IAU2000) (2000)
- *Mars*: Mars (IAU2000) (2000)
- *Jupiter*: Jupiter (IAU2000) (2000)
- *Saturn*: Saturn (IAU2000) (2000)
- *Uranus*: Uranus (IAU2000) (2000)
- *Neptune*: Neptune (IAU2000) (2000)
- *Pluto*: Pluto (IAU2000) (2000)
Note that for some global projections, GMT may use a spherical
approximation of the ellipsoid chosen, setting the flattening to
zero, and using a mean radius. A warning will be given when this
happens. If a different ellipsoid name than those mentioned here is
given, GMT will attempt to parse the name to extract the
semi-major axis (**a** in m) and the flattening. Formats allowed are:
**a** implies a zero flattening
**a**,\ *inv_f* where *inv_f* is the inverse flattening
**a**,\ **b=**\ *b* where *b* is the semi-minor axis (in m)
**a**,\ **f=**\ *f* where *f* is the flattening
This way a custom ellipsoid (e.g., those used for other planets) may
be used. Further note that coordinate transformations in
**mapproject** can also specify specific datums; see the
:doc:`mapproject` man page for further details and how to view
ellipsoid and datum parameters.
**PROJ_GEODESIC**
Selects the algorithm to use for geodesic calculations. Choose between
**Vincenty**, **Rudoe**, or **Andoyer**. The **Andoyer**
algorithm is only approximate (to within a few tens of meters) but is
up to 5 times faster. The **Rudoe** is given for legacy purposes.
[default is **Vincenty** *(accurate to about 0.5 mm)*].
**PROJ_LENGTH_UNIT**
Sets the default unit length. Choose between **c**\ m, **i**\ nch, or
**p**\ oint [default is **c** *(or i)*]. **Note**: In GMT, one point is
defined as 1/72 inch (the PostScript definition), while it is often
defined as 1/72.27 inch in the typesetting industry. There is no universal
definition.)
**PROJ_MEAN_RADIUS**
Applies when geodesics are approximated by great circle distances on
an equivalent sphere or when surface areas are computed. Select from
**mean** (R_1), **authalic** (R_2), **volumetric** (R_3), **meridional**,
or **quadratic** [default is **authalic**].
**PROJ_SCALE_FACTOR**
Changes the default map scale factor used for the Polar
Stereographic [default is **0.9996**], UTM [default is **0.9996**],
and Transverse Mercator [default is **1**]
projections in order to minimize areal distortion. Provide a new
scale-factor or leave as default.
.. glossary::
**PS_CHAR_ENCODING**
(*static*) Names the eight bit character set being used for text in
files and in command line parameters. This allows GMT to ensure that the
PostScript output generates the correct characters on the plot. Choose from
**Standard**, **Standard+**, **ISOLatin1**, **ISOLatin1+**, and
**ISO-8859-x** (where *x* is in the ranges 1-11 or 13-16). See Appendix F
for details [default is **ISOLatin1+** *(or Standard+)*]. **Note**:
Normally the character set is written as part of the PostScript header.
If you need to switch to another character set for a later overlay then
you must use **--PS_CHAR_ENCODING**\ =\ *encoding* on the command line
and not via gmt :doc:`/gmtset`. Finally, note 6, 8, and 11 do not work
with standard fonts.
**PS_COLOR_MODEL**
Determines whether PostScript output should use **RGB**, **HSV**, **CMYK**,
or **GRAY** when specifying color [default is **rgb**]. Note if **HSV**
is selected it does not apply to images which in that case uses **RGB**.
When selecting **GRAY**, all colors will be converted to gray scale using
YIQ (television) conversion.
**PS_COMMENTS**
(*static*) If **true** we will issue comments in the PostScript file
that explain the logic of operations. These are useful if you need
to edit the file and make changes; otherwise you can set it to **false**
which yields a somewhat slimmer PostScript file [default is **false**].
**PS_CONVERT**
Comma-separated list of optional module arguments that we should supply
when :doc:`psconvert` is called implicitly under modern mode [**A**].
Ignored when psconvert is called on the command line explicitly.
The option arguments must be listed without their leading option hyphen.
**PS_IMAGE_COMPRESS**
Determines if PostScript images are compressed using the Run-Length
Encoding scheme (**rle**), Lempel-Ziv-Welch compression (**lzw**), DEFLATE
compression (**deflate**\ [,\ *level*]), or not at all (**none**) [default
is **deflate,5**]. When specifying **deflate**, the compression level
(1–9) may optionally be appended.
**PS_LINE_CAP**
Determines how the ends of a line segment will be drawn. Choose
among a **butt** cap where there is no projection beyond the
end of the path, a **round** cap where a semicircular arc with
diameter equal to the line-width is drawn around the end points, and
**square** cap where a half square of size equal to the line-width
extends beyond the end of the path [default is **butt**].
**PS_LINE_JOIN**
Determines what happens at kinks in line segments. Choose among a
**miter** join where the outer edges of the strokes for the two
segments are extended until they meet at an angle (as in a picture
frame; if the angle is too acute, a bevel join is used instead, with
threshold set by :term:`PS_MITER_LIMIT`), **round** join where a
circular arc is used to fill in the cracks at the kinks, and **bevel**
join which is a miter join that is cut off so kinks are triangular in
shape [default is **miter**].
**PS_MEDIA**
*Classic mode:* Sets the physical size of the current plotting paper
[default is **a4** *(or letter)*]. *Modern mode:* If user selects
PostScript output then the above applies as well. For other graphics
formats (PDF and rasters), the media size is determined automatically
by cropping to fit the plot exactly (but see :term:`PS_CONVERT`). However,
if a specific media size is desired then the :term:`PS_MEDIA` may be
specified as well. The following formats (and their widths and heights
in points) are recognized:
======== ======== ======== ========== ======== ========
Media width height Media width height
======== ======== ======== ========== ======== ========
A0 2380 3368 archA 648 864
A1 1684 2380 archB 864 1296
A2 1190 1684 archC 1296 1728
A3 842 1190 archD 1728 2592
A4 595 842 archE 2592 3456
A5 421 595 flsa 612 936
A6 297 421 halfletter 396 612
A7 210 297 statement 396 612
A8 148 210 note 540 720
A9 105 148 letter 612 792
A10 74 105 legal 612 1008
B0 2836 4008 11x17 792 1224
B1 2004 2836 tabloid 792 1224
B2 1418 2004 ledger 1224 792
B3 1002 1418
B4 709 1002
B5 501 709
======== ======== ======== ========== ======== ========
For a completely custom format (e.g., for large format plotters) you may
also specify **WxH**, where **W** and **H** are in points unless you append
a unit to each dimension (**c**, **i**, **m** or **p** [default is **p**]).
Additional user-specific formats may be saved as separate line in a
gmt_custom_media.conf file stored in ~/.gmt. Each record would have a
format name followed by width and height of your media in points. For
infinitely long paper rolls (e.g., plotters you can set height = 0).
**PS_MITER_LIMIT**
Sets the threshold angle in degrees (integer in range [0,180]) used
for mitered joins only. When the angle between joining line segments
is smaller than the threshold the corner will be bevelled instead of
mitered [default is **35**]. Setting the threshold
angle to **0** implies the PostScript default of about 11 degrees.
Setting the threshold angle to **180** causes all joins to be beveled.
**PS_PAGE_COLOR**
Sets the color of the imaging background, i.e., the paper [default is **white**].
**PS_PAGE_ORIENTATION**
(**-P**) Sets the orientation of the page. Choose portrait or
landscape [default is **landscape**]. Only available in GMT classic mode.
**PS_SCALE_X**
Global x-scale (> 0) to apply to plot-coordinates before plotting.
Normally used to shrink the entire output down to fit a specific
height/width [default is **1.0**].
**PS_SCALE_Y**
Global y-scale (> 0) to apply to plot-coordinates before plotting.
Normally used to shrink the entire output down to fit a specific
height/width [default is **1.0**].
**PS_TRANSPARENCY**
Sets the transparency mode to use when preparing PS for rendering to
PDF. Choose from **Color**, **ColorBurn**, **ColorDodge**, **Darken**,
**Difference**, **Exclusion**, **HardLight**, **Hue**, **Lighten**,
**Luminosity**, **Multiply**, **Normal**, **Overlay**, **Saturation**,
**SoftLight**, and **Screen** [default is **Normal**]. For more information,
see `blend modes <https://en.wikipedia.org/wiki/Blend_modes>`_.
.. glossary::
**TIME_EPOCH**
Specifies the value of the calendar and clock at the origin (zero
point) of relative time units (see :term:`TIME_UNIT`). It is a string
of the form **yyyy-mm-ddT[hh:mm:ss]** (Gregorian) or
**yyyy-Www-ddT[hh:mm:ss]** (ISO) [default is **1970-01-01T00:00:00**
*(the origin of the UNIX time epoch*)].
**TIME_INTERVAL_FRACTION**
Determines if partial intervals at the start and end of an axis
should be annotated. If the range of the partial interval exceeds
the specified fraction of the normal interval stride we will place
the annotation centered on the partial interval [default is **0.5**].
**TIME_IS_INTERVAL**
Used when input calendar data should be truncated and adjusted to
the middle of the relevant interval. In the following discussion,
the unit *unit* can be one of these time units: (**y** year, **o**
month, **u** ISO week, **d** day, **h** hour, **m** minute, and
**s** second). **TIME_IS_INTERVAL** can have any of the following
three values: (1) **OFF** : no adjustment, time is decoded as
given. (2) **+n**\ *unit* : activate interval adjustment for input by
truncate to previous whole number of *n* units and then center time
on the following interval. (3) **-n**\ *unit*. Same, but center time on
the previous interval [default is **off**]. For example, with
**TIME_IS_INTERVAL** =+1o, an input data string like 1999-12 will be
interpreted to mean 1999-12-15T12:00:00.0 (exactly middle of December),
while if **TIME_IS_INTERVAL** = **off** then that date is interpreted
to mean 1999-12-01T00:00:00.0 (start of December).
**TIME_REPORT**
Controls if a time-stamp should be issued at start of all progress
reports. Choose among **clock** (absolute time stamp),
**elapsed** (time since start of session), or **none**
[default is **none**]. The format of the timer is controlled by
:term:`FORMAT_TIME_STAMP`.
**TIME_SYSTEM**
Shorthand for a combination of :term:`TIME_EPOCH` and :term:`TIME_UNIT`,
specifying which time epoch the relative time refers to and what the
units are. Choose from one of the preset systems below (epoch and
units are indicated):
============ ====================== =========== =====================
TIME_SYSTEM TIME_EPOCH TIME_UNIT Notes
============ ====================== =========== =====================
JD -4713-11-25T12:00:00 d Julian Date
MJD 1858-11-17T00:00:00 d Modified Julian Date
J2000 2000-01-01T12:00:00 d Astronomical time
S1985 1985-01-01T00:00:00 s Altimetric time
UNIX 1970-01-01T00:00:00 s UNIX time
RD0001 0001-01-01T00:00:00 s
RATA 0000-12-31T00:00:00 d
============ ====================== =========== =====================
This parameter is not stored in the **gmt.conf** file but is
translated to the respective values of :term:`TIME_EPOCH` and
:term:`TIME_UNIT`.
**TIME_UNIT**
Specifies the units of relative time data since epoch (see
:term:`TIME_EPOCH`). Choose **y** (year - assumes all years are 365.2425
days), **o** (month - assumes all months are of equal length y/12), **w**
(week), **d** (day), **h** (hour), **m** (minute), or **s** (second) [default is **s**].
**TIME_WEEK_START**
When weeks are indicated on time axes, this parameter determines the
first day of the week for Gregorian calendars. (The ISO weekly
calendar always begins weeks with Monday.) [default is **Monday** *(or Sunday)*].
**TIME_Y2K_OFFSET_YEAR**
When 2-digit years are used to represent 4-digit years (see various
**FORMAT_DATE**\ s), :term:`TIME_Y2K_OFFSET_YEAR` gives the first
year in a 100-year sequence. For example, if
:term:`TIME_Y2K_OFFSET_YEAR` is 1729, then numbers 29 through 99
correspond to 1729 through 1799, while numbers 00 through 28
correspond to 1800 through 1828 [default is **1950**].
:doc:`gmt`, :doc:`gmtdefaults`, :doc:`gmtcolors`, :doc:`gmtget`, :doc:`gmtset`