[Gdal-dev] Problems with gdal_grid

[Tamas Szekeres]

Nicolas,

I'm afraid I don't see the problem exactly. You should create a
similar vrt file as I've included in my previous post. Then you should
probably use CreateCopy to copy the virtual raster to a "real" raster
format png/jpg whatever. Or use an application like gdal_translate to
accomplish this task.

Best regards,

Tamas


2008/4/18, PikoBoZ <piklas at gmail.com>:
>
>  Hi List
>  Thanks to Andrey and Tamas for their useful answers about .vrt
>  I managed to write a simple .vrt and to interpolate my point values using -a
>  invdist.
>  I'm now trying to control my layer style and nodata
>  I understood that i must use the ComplexSource to perform such tasks, as
>  Tamas show me an example.
>  Is the ComplexSource must be embedded into the
>  <OGRVRTDataSource></OGRVRTDataSource>, or must it comes after, or may be in
>  a different file ?
>  In fact i don't get the solution to link the VRTDataSource and the
>  ComplexSource
>  Any hints appreciated
>
>  Nicolas B.
>
>
>
>  PikoBoZ wrote:
>  >
>  > Hi List !
>  >
>  > I've got troubles experimenting gdal_grid interpolation algoritms
>  > I want to interpolate ponctual values contained in a point .shp (or csv),
>  > and to write the result as GTiff
>  > I use the following command yet:
>  >
>  > [code]
>  > gdal_grid -a invdist:power=2.0smooting=1.0 -txe 679285 681415 -tye 1837728
>  > 1840022 -of GTiff -ot Float32 -l vectorial_plume vectorial_plume.shp
>  > testwrite.tiff
>  > [/code]
>  >
>  > testwrite.tiff is created but corrupted:
>  > - It is mono band greyscaled, and i'd like to get a RGB, in the aim to
>  > apply style
>  > - It is all black (NoData). I think that gdal doesn't know on which field
>  > to work on (in the dbf) so it can't interpolate any values !
>  >
>  > So, a few questions is persiting in my mind:
>  > Is it simpler to interpolate from .shp or to use a .vrt / .csv couple ?
>  > How can I specify to gdal_grid a data field to interpolate?
>  > Is it possible to get a RGB GTiff from gdal_grid and to apply style
>  > (killing nodata, Min/Max colors...)
>  >
>  > Many thanks by advance
>  >
>  > Nicolas BOZON
>  > Maths/GIS PhD student
>  >
>  >
>  >
>  >
>  >
>  >
>
>  --
>
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>
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