[gdal-dev] create a png file

Jorge Arevalo jorgearevalo at gis4free.org
Thu Apr 8 13:15:51 EDT 2010


On Wed, Apr 7, 2010 at 5:09 AM, weixj2003ld <weixj2003ld at 163.com> wrote:
> Thk u for your reply.
> I read the tuorail.but I think that will not satisfy my need.
> I want to create a .png file,and it only contains height data and not
> contains metadata, a coordinate system, a georeferencing transform, size of
> raster and various other information,I find that the Create() and
> CreateCopy(). is will create a file that contains all the things.
> Kind regards.

A PNG file itself can't store metadata, like a GeoTiff file. You'll
need to create an external world file to store it. Please take a read
at this, from http://www.gdal.org/frmt_various.html

"PNG files can be created with a type of PNG, using the CreateCopy()
method, requiring a prototype to read from. Writing includes support
for the various image types, and will preserve transparency/nodata
values. Georeferencing .wld files are written if option WORLDFILE
setted. All pixel types other than 16bit unsigned will be written as
eight bit.

Creation Options:

WORLDFILE=YES: Force the generation of an associated ESRI world file
(with the extension .wld). See World File section for details."

Best regards,

> Please refer to http://www.gdal.org/gdal_tutorial.html
> 2010/4/6 weixj2003ld <weixj2003ld at 163.com>
>> I read data from a DEM file, and want to create a .png .Now I have read
>> data, but I do not know how to create a png file that contains the height
>> map value of each point from the DEM file.
>> Thk u.
>> _______________________________________________
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>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> --
> Best regards,
> Chaitanya kumar CH.
> /tʃaɪθənjə/ /kʊmɑr/
> +91-9848167848
> 17.2416N 80.1426E
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