[GRASS-user] Looking for technique to equalize shading of adjacent Aster dem tiles

GRASS GRASS user
1


Hi,
I’m using GRASS GIS to help me model the Rouen les Essarts race course.



One of my aims is to take a nice grayscale image to use in deforming mesh topology. The circuit straddles two tiles and the shading is markedly different.



How can I either fix one or re-color both from scratch based on the elevation data?



Should be trying to get tessellations right out of the application?



Thank you
2

One of my aims is to take a nice grayscale image to use in deforming mesh

topology. The circuit straddles >two tiles and the shading is markedly
different.

How can I either fix one or re-color both from scratch based on the

elevation data?

maybe build a virtual gdal data set [1] [2] of the Aster dem tiles, link [3]
or import [4] them and use these tiles as one dem dataset for shading?

[1] http://www.gdal.org/gdalbuildvrt.html
[2] http://www.gdal.org/gdal_vrttut.html
[3] http://grass.osgeo.org/grass64/manuals/html64_user/r.external.html
[4] http://grass.osgeo.org/grass64/manuals/html64_user/r.in.gdal.html

-----
best regards
Helmut
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3

Or maybe you could use the r.patch command to combine them into one raster with one colortable.

On Mon, Jun 4, 2012 at 3:36 PM, Helmut Kudrnovsky <hellik@web.de> wrote:

One of my aims is to take a nice grayscale image to use in deforming mesh
topology. The circuit straddles >two tiles and the shading is markedly
different.

How can I either fix one or re-color both from scratch based on the
elevation data?

maybe build a virtual gdal data set [1] [2] of the Aster dem tiles, link [3]
or import [4] them and use these tiles as one dem dataset for shading?

[1] http://www.gdal.org/gdalbuildvrt.html
[2] http://www.gdal.org/gdal_vrttut.html
[3] http://grass.osgeo.org/grass64/manuals/html64_user/r.external.html
[4] http://grass.osgeo.org/grass64/manuals/html64_user/r.in.gdal.html

best regards
Helmut

View this message in context: http://osgeo-org.1560.n6.nabble.com/Looking-for-technique-to-equalize-shading-of-adjacent-Aster-dem-tiles-tp4978868p4978907.html
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