[gdal-dev] RE: ECW projection data using Dataset.GetProjectionRef()

[Henneke, Amanda M]

Hi Kris-

You wouldn't by any chance have opened these geotiffs in ERDAS Imagine have you?  Are there .aux or .rrd files associated with these images?

Thanks,
Amanda

Amanda M. Henneke

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________________________________
From: gdal-dev-bounces at lists.osgeo.org [mailto:gdal-dev-bounces at lists.osgeo.org] On Behalf Of Kris Pribadi
Sent: Tuesday, October 20, 2009 1:19 PM
To: gdal-dev at lists.osgeo.org
Subject: [gdal-dev] ECW projection data using Dataset.GetProjectionRef()

Hi:

I am a new GDAL user using C#.

I am using C# implementation of GDAL from FW_Tools. I am trying to write a C# program similar to gdalinfo to extract the metadata from raster files. It is working fine with GeoTiff files, but having problem reading ECW metadata file. The spatial projection  "_projectionWKT" info returns "null". However, when I use gdalinfo, it prints out the ECW file coordinate system as WGS_84, which is correct. Does gdalinfo assume "WGS_84" if GetProjectionRef() is null? How does it get the projection info from ECW file?

I appreciate any help or suggestions.

Thanks
Kris

This is the fields definition:
  OSGeo.GDAL.Dataset _ds;
        SpatialReference _srs;
        SpatialProjectionInfo _projectionInfo;


This is my program:

                OSGeo.GDAL.Gdal.AllRegister(); //Register drivers.
                OSGeo.OGR.Ogr.RegisterAll();

                _ds = OSGeo.GDAL.Gdal.Open(Filename, OSGeo.GDAL.Access.GA_ReadOnly); //Open dataset from files


                if (_ds == null)
                {
                    throw new Exception("The files could not be loaded");
                }

                //TODO May fail if wrong file type?
                _ds.GetGeoTransform(_dbGeoTrans);

                //TODO projectionWKT may be null if no info from the file.
                //THIS RETURNS NULL FOR "ECW" FILES
                _projectionWKT = _ds.GetProjectionRef();

                Console.WriteLine("Projection WKT: " + _projectionWKT);

                //Get Spatial Information
                _projectionInfo = new SpatialProjectionInfo(projectionWKT);
                bool _IsGeopgraphic = _projectionInfo.IsGeographic;
                bool _IsProjected = _projectionInfo.IsProjected;
                _srs = _projectionInfo.SpatialReference;


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