2

I have a tif image containing its CRS. I would like to extract the parameter "central_meridian". I have the following piece of code:

from osgeo import gdal,osr ds=gdal.Open(r'hrs0000bf5c_07_if177l_trr3_CAT_scale_trial_p.img.tif') prj=ds.GetProjection() print prj srs=osr.SpatialReference(wkt=prj) print srs.GetAttrValue('PARAMETER',0) print srs.GetAttrValue('PARAMETER',1)

The output I get is the following:

 PROJCS["Mars_Npolar_Stereo",GEOGCS["GCS_Unknown",DATUM["Unknown",SPHEROID["S_Unknown",3396190,169.8944472236118]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433]],PROJECTION["Polar_Stereographic"],PARAMETER["latitude_of_origin",90],PARAMETER["central_meridian",160.0712280273438],PARAMETER["scale_factor",1],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]]] latitude_of_origin 90

I would like to fetch the second parameter "central_meridian" but i don't know how to do it? Any ideas?

##EDIT

If trying to open a list of files given by a list like:

from osgeo import gdal,osr from gdalconst import GA_ReadOnly

f = open('list.txt') for line in iter(f): print line ds=gdal.Open(line,GA_ReadOnly) prj=ds.GetProjection() srs=osr.SpatialReference(wkt=prj) print line + " " + srs.GetProjParm( osr.SRS_PP_CENTRAL_MERIDIAN) f.close()

I get the following error: ERROR 4: `frt0000703c_07_if187l_trr3_CAT_scale_trial_p.img.tif ' does not exist in the file system, and is not recognised as a supported dataset name.

I tried different ways to do it and went through documentation but no luck. Any ideas why it does not recognizes it as a filename?

Improve this question
0

1 Answer 1

Reset to default
4

You could use the OGRSpatialReference::GetProjParm to obtain the central meridian value as described in the GDAL tutorial for Querying Coordinate System:

srs.GetProjParm( osr.SRS_PP_CENTRAL_MERIDIAN)

So you could use:

from osgeo import gdal,osr ds = gdal.Open(r'hrs0000bf5c_07_if177l_trr3_CAT_scale_trial_p.img.tif') prj = ds.GetProjection() srs = osr.SpatialReference(wkt=prj) srs.GetProjParm( osr.SRS_PP_CENTRAL_MERIDIAN)
Improve this answer
4
  • @ramayer - Most welcome, glad it worked =) Commented Oct 18, 2016 at 12:25
  • I know it might sound super silly the question but I am trying to do this iterative given a list of files like this: Commented Oct 18, 2016 at 12:30
  • @ramayer - I would probably suggest asking this as a new question. Perhaps you need to specify the full paths in your .txt file? Commented Oct 18, 2016 at 12:50
  • indeed. filePath="/storage/esp-data/data/data/MARS/MRO/CRISM/TRDR/mrocr_2102/processed_mrocr_2102/tif/" + line ds=gdal.Open(filePath.strip()) Commented Oct 18, 2016 at 13:09

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.