Modifier +s not working when the symbol code is given in the last column of the input

[seisman]

Description of the problem
According to the documentation, one can simply give x and y coordinates of start and end point when plotting vectors with +s modifier.

gmt/doc_modern/rst/source/explain_vectors.rst_

Lines 71 to 72 in c1a5c7c

	**+s** means the input *angle*, *length* are instead the *x*, *y*
	coordinates of the vector end point.

Full script that generated the error

The following script plots two arrows, one with symbol code in the command line and the other one in the last column of the input.

gmt begin GMT_arrows png
echo 0.5 1.5 4.5 1.5 | gmt plot -R0/5/0/5 -Baf -JX1.75i -Sv0.2i+s+b+e -W1.5p -Gred
echo 0.5 3.5 4.5 3.5 v0.2i+s+b+e | gmt plot -R0/5/0/5 -Baf -JX1.75i -S -W1.5p -Gred
gmt end

Output figure:

System information

• Operating system: macOS
• Version of GMT: 6.0.0 c1a5c7c

[PaulWessel]

I am fixing this issue. I expect using +s in the data file will work unless you are specially formatted coordinates lind ddd:mm:ss since the data parser probably may not handle a sudden switch of column format. However, I have not checked to see if that is true, but my fix for this issue works. I will create a pull request shortly.