The library is basically written as a wrapper around liblwgeom which comes with PostGIS. Liblwgeom uses following libraries in order to perform geospatial calculations.
The library containes some extra functions which uses libgeos directly.
# Add ubuntugis repository
sudo apt-add-repository -y ppa:ubuntugis/ubuntugis-unstable
sudo apt-get install libgeos-dev libgeos-3.7.0 liblwgeom-2.5-0 liblwgeom-dev libproj-dev
You can download the source code from https://trac.osgeo.org/geos/.
More on: https://trac.osgeo.org/geos#BuildandInstall
Building GEOS requires a C++11 compiler
# Install gcc and cmake
sudo apt install gcc
sudo apt install cmake
Below are the compilation steps
# Commpilation
wget http:https://download.osgeo.org/geos/geos-3.7.1.tar.bz2
tar xvfj geos-3.7.1.tar.bz2
cd geos-3.7.1
mkdir build && cd build
cmake ..
make
make check
# Installation. Should be executed with superuser privileges
sudo make install
# Create necessary links
sudo ldconfig
package main
import (
"fmt"
"github.com/srimaln91/go-geom/geom"
)
func main() {
jsonLineString := `{
"type": "LineString",
"coordinates": [
[79.86064,6.933669],
[79.87326,6.923529],
[79.87017,6.910237],
[79.88305,6.899671],
[79.89008,6.890724],
[79.89051,6.882118],
[79.88854,6.869762],
[79.87532,6.863541]
]
}`
lwgeom, err := geom.FromGeoJSON(jsonLineString)
if err != nil {
fmt.Println(err)
return
}
lwgeom.SetSRID(4326)
defer lwgeom.Free()
lwgeom.LineSubstring(0.5, 0.9)
fromSRS := geom.SRS["EPSG:4326"]
toSRS := geom.SRS["EPSG:3857"]
// Transform the geometry to SRS EPSG:3757 so we can measure from metres.
lwgeom.Project(fromSRS, toSRS)
lwgeom.Buffer(200)
// Reset SRS to EPSG:4326
lwgeom.Project(toSRS, fromSRS)
bufJSON, err := lwgeom.ToGeoJSON(4, 0)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(bufJSON)
}