Some shapefiles have a .prj file associated with it, and the .prj file contains the projection info of the shapefile in the format of WKT. Sometimes I need to convert WKT to proj4 string, and sometimes I need to convert it back.
Is there any ready-made library to do this?
The OGR Spatial Reference part of GDAL should do the trick. capooti provided an excellent answer to another question which demonstrates how to peform the translation from a shapefile to WKT. You may also want to check out the class reference. The reverse is simply:
from osgeo import osr
srs = osr.SpatialReference()
wkt_text = 'GEOGCS["GCS_WGS_1984",DATUM["WGS_1984",' \
'SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],'\
'UNIT["Degree",0.017453292519943295]]'
# Imports WKT to Spatial Reference Object
srs.ImportFromWkt(wkt_text)
srs.MorphToESRI() # converts the WKT to an ESRI-compatible format
print "ESRI compatible WKT for use as .prj:" % srs.ExportToWkt()
osgeo, which doesn't seem to work for Python 3?
– Dan Nguyen
Feb 22 '16 at 2:51
ExportToProj4() in the last line instead?
– astrojuanlu
Jun 23 '17 at 8:08
You can also use PyCRS:
import pycrs
print(pycrs.parser.from_esri_wkt(wkt_text).to_proj4())
# +proj=longlat +ellps=WGS84 +a=6378137.0 +f=298.257223563 +pm=0.0 +no_defs
I don't know any library, but you can use this site to get the translations: http://spatialreference.org/
EDIT: I found a python script that works with ogr python bindings to do that. Here it is.
I need to pragrammatically transform to custom projection based on proj4text string, so used
projection = '+proj=lcc +lat_1=53 +lat_2=70 +lat_0=0 +lon_0=136 +x_0=0 +y_0=0 +ellps=intl +units=m +no_defs'
source = osr.SpatialReference()
source.ImportFromEPSG(4326)
target = osr.SpatialReference()
target.ImportFromProj4(projection)
transform = osr.CoordinateTransformation(source, target)
