What is the best way to programmatically convert between WKT and Proj4 string?

Question

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?

score 14 · Answer 1 · edited Sep 27 '22 at 13:36

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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()

edited Sep 27 '22 at 13:36

Glorfindel

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answered Apr 14 '11 at 16:47

scw

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Anyone have a solution that doesn't require osgeo, which doesn't seem to work for Python 3? – dancow Feb 22 '16 at 02:51
OP asked about Proj4. Did you mean ExportToProj4() in the last line instead? – astrojuanlu Jun 23 '17 at 08:08

score 3 · Answer 2 · answered Jun 23 '17 at 08:22

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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

answered Jun 23 '17 at 08:22

astrojuanlu

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Pablo · Answer 3 · 2011-04-14T16:39:32.523

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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.

edited Apr 14 '11 at 16:39

answered Apr 14 '11 at 16:08

Pablo

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thanks, but i need to do that programmatically. – Cui Pengfei 崔鹏飞 Apr 14 '11 at 16:11
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After some googling: spatialreference.org is powered by GDAL as well & uses the same code path (more or less), it seems. – Dan S. Apr 14 '11 at 17:11
That's interesting – Pablo Apr 14 '11 at 18:33

score 0 · Answer 4 · answered Jul 03 '18 at 10:19

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)

What is the best way to programmatically convert between WKT and Proj4 string?

4 Answers4

Imports WKT to Spatial Reference Object

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