[gdal-dev] The problem when using ReadRaster(C#) method

[Tamas Szekeres]

You should make sure about the actual representation of the raster image,
whether it represents the pixel as floats as you have used float arrays in
the code. The last 2 parameters are used to define the byte offset of the
pixels and lines in the image ( for more info see the
RasterIO<http://www.gdal.org/classGDALRasterBand.html#5497e8d29e743ee9177202cb3f61c3c7>documentation).

Further C# related samples can be found here:
http://trac.osgeo.org/gdal/browser/trunk/gdal/swig/csharp/apps/GDALRead.cs
http://trac.osgeo.org/gdal/browser/trunk/gdal/swig/csharp/apps/GDALReadDirect.cs

Best regards,

Tamas



2011/8/31 hitweiran <hitweiran at sina.com>

> I want to read a multiband image(in format of .img) by using method
> ReadRaster, however, I encount some problems. I just can't understand why
> the data loaded to memory is wrong?
> the code is like this
>
> OSGeo.GDAL.Dataset dataSet =
> OSGeo.GDAL.Gdal.Open(@"G:\building.img",OSGeo.GDAL.Access.GA_ReadOnly);
> int width = dataSet.RasterXSize;
> int height = dataSet.RasterYSize;
> int Band_Numbers = dataSet.RasterCount;
> float [] buffer_first = new float [width * height];
> OSGeo.GDAL.Band One_Band = dataSet.GetRasterBand(1);
> One_Band.ReadRaster(0, 0, width, height,buffer_first, width, height, 0,0);
>
> However, the output is wrong!
> I watch the variable "buffer_first" in watch window, and discoverse that
> the
> data is quite terrible-some data is such as 2.818478E+21,5.065476E+32, or
> -6.131138E-11 and so on;
> So I suspect my datatype is mismatch to data in img file, or the last two
> arguments in ReadRaster is mistake, because I don't know the meaning of
> last
> two parameters.
> Thanks a lot for your answer!
>
> --
> View this message in context:
> http://osgeo-org.1803224.n2.nabble.com/The-problem-when-using-ReadRaster-C-method-tp6745826p6745826.html
> Sent from the GDAL - Dev mailing list archive at Nabble.com.
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20110831/266b56dc/attachment.html