[GRASS-user] Accentuating/adding topography to a raster image?

Dylan Beaudette dylan.beaudette at gmail.com
Sat Aug 12 15:36:04 EDT 2006


Hi Jonathan, others,

I have done somehting similar for very large datasets: i.e. a 30m DEM
for CA, then AZ, and then finally NV.


Here is what I did, all without memory problems: all sizes are approx.

1. patch together my DEM data (2.5 Gb)
2. compute shaded rel. via r.shaded.relief (1.5Gb)
3. patch 30m landsat tiles and create *nice* color composites 4x (1.5Gb)
4. blend shaded relief and landsat composite 3x (2gb)
5. re-composite blened output channels (4Gb)
6. tile resulting raster for speedy access via mapserver

do this for each state...

a quick example can be seen here:

http://casoilresource.lawr.ucdavis.edu/drupal/node/253?size=_original

or on the actual online soil survey itself:
http://casoilresource.lawr.ucdavis.edu/drupal/node/27

note that CA and NV look the best, still working on re-doing AZ with
the i.landsat.rgb module:
http://casoilresource.lawr.ucdavis.edu/drupal/node/159


the actual computations tool several hours, so i would leave the
machine to do its work overnight, usually to find the output the next
morning. I would estimate at least 2 days of computer time (2x Xeon
2.8 GHz) for something this size.


hope that is helpful,

Dylan

On 8/12/06, Michael Barton <michael.barton at asu.edu> wrote:
> DEFINITELY drop your resolution before running nviz (or even making a shaded
> relief map) unless you want to take all night to display stuff. This will
> have a much bigger effect than the size of the image per se.
>
> Michael
> __________________________________________
> Michael Barton, Professor of Anthropology
> School of Human Evolution & Social Change
> Center for Social Dynamics & Complexity
> Arizona State University
>
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
>
>
>
> > From: Jachym Cepicky <jachym.cepicky at centrum.cz>
> > Date: Sat, 12 Aug 2006 20:12:48 +0200
> > To: Jonathan Greenberg <jgreenberg at arc.nasa.gov>
> > Cc: 'GRASS user list' <grassuser at grass.itc.it>
> > Subject: Re: [GRASS-user] Accentuating/adding topography to a raster image?
> >
> > what about resample your resolution?
> >
> >     g.region res=*MORE*
> >
> > result could be still printable, but it would not be so big
> >
> > jachym
> >
> > On Sat, Aug 12, 2006 at 11:00:28AM -0700, Jonathan Greenberg wrote:
> >> My main problem is the dem and image are both about 1.5 gb each -- am I
> >> likely to run into problems with this?
> >>
> >> Never played with nviz before, looks like I'll be trying it out tonight!
> >>
> >> --j
> >>
> >> --
> >>
> >> Jonathan A. Greenberg, PhD
> >> NASA Postdoctoral Researcher
> >> NASA Ames Research Center
> >> MS 242-4
> >> Moffett Field, CA 94035-1000
> >> Phone: 415-794-5043
> >> AIM: jgrn3007
> >> MSN: jgrn3007 at hotmail.com
> >>
> >> -----Original Message-----
> >> From: Michael Barton [mailto:michael.barton at asu.edu]
> >> Sent: Saturday, August 12, 2006 10:54 AM
> >> To: Jachym Cepicky; Jonathan Greenberg
> >> Cc: 'GRASS user list'
> >> Subject: Re: [GRASS-user] Accentuating/adding topography to a raster image?
> >>
> >> This is also automatically done in the GUI. Just put your shaded relief map
> >> into the basemap field and your image into the drape map field.
> >>
> >> Display and presto, you have a topographically shaded image.
> >>
> >> You can also do this in nviz for an even more dramatic effect. Use a DEM
> >> (not shaded relief) as a basemap/elevation map and use your image as a color
> >> map for the topography.
> >>
> >> Michael
> >> __________________________________________
> >> Michael Barton, Professor of Anthropology
> >> School of Human Evolution & Social Change
> >> Center for Social Dynamics & Complexity
> >> Arizona State University
> >>
> >> phone: 480-965-6213
> >> fax: 480-965-7671
> >> www: http://www.public.asu.edu/~cmbarton
> >>
> >>
> >>
> >>> From: Jachym Cepicky <jachym.cepicky at centrum.cz>
> >>> Date: Sat, 12 Aug 2006 12:27:33 +0200
> >>> To: Jonathan Greenberg <jgreenberg at arc.nasa.gov>
> >>> Cc: 'GRASS user list' <grassuser at grass.itc.it>
> >>> Subject: Re: [GRASS-user] Accentuating/adding topography to a raster
> >> image?
> >>>
> >>> Hi,
> >>>
> >>> I use this approach:
> >>>
> >>> d.his h=your_map i=aspect
> >>>
> >>> or
> >>>
> >>> d.his h=your_map i=r_shaded_relief
> >>>
> >>> or run nviz and set the light source ;-)
> >>>
> >>> jachym
> >>>
> >>>
> >>> On Sat, Aug 12, 2006 at 02:45:22AM -0700, Jonathan Greenberg wrote:
> >>>> We're trying to add in a bit of topographic shading/illumination into an
> >>>> image, and I was hoping to get some feedback on what algorithms work the
> >>>> best?  I tried a hillshade approach in ENVI, was pretty unimpressed with
> >> it.
> >>>> Any suggestions for a GRASS approach?  Run r.sun and do some sort of
> >> pixel
> >>>> weighting?
> >>>>
> >>>> --j
> >>>>
> >>>> --
> >>>>
> >>>> Jonathan A. Greenberg, PhD
> >>>> NASA Postdoctoral Researcher
> >>>> NASA Ames Research Center
> >>>> MS 242-4
> >>>> Moffett Field, CA 94035-1000
> >>>> Phone: 415-794-5043
> >>>> AIM: jgrn3007
> >>>> MSN: jgrn3007 at hotmail.com
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> grassuser mailing list
> >>>> grassuser at grass.itc.it
> >>>> http://grass.itc.it/mailman/listinfo/grassuser
> >>>
> >>> --
> >>> Jachym Cepicky
> >>> e-mail: jachym.cepicky at centrum.cz
> >>> URL: http://les-ejk.cz
> >>> GPG: http://les-ejk.cz/gnupg_public_key/jachym_cepicky-gpg_public_key.asc
> >>> -----------------------------------------
> >>> OFFICE:
> >>> GDF-Hannover
> >>> Mengendamm 16d
> >>> 30177 Hannover
> >>> Germany
> >>> e-mail: cepicky at gdf-hannover.de
> >>> URL:    http://gdf-hannover.de
> >>> Tel.:   +49 511-39088507
> >>
> >>
> >> _______________________________________________
> >> grassuser mailing list
> >> grassuser at grass.itc.it
> >> http://grass.itc.it/mailman/listinfo/grassuser
> >
> > --
> > Jachym Cepicky
> > e-mail: jachym.cepicky at centrum.cz
> > URL: http://les-ejk.cz
> > GPG: http://les-ejk.cz/gnupg_public_key/jachym_cepicky-gpg_public_key.asc
> > -----------------------------------------
> > OFFICE:
> > GDF-Hannover
> > Mengendamm 16d
> > 30177 Hannover
> > Germany
> > e-mail: cepicky at gdf-hannover.de
> > URL:    http://gdf-hannover.de
> > Tel.:   +49 511-39088507
>
> _______________________________________________
> grassuser mailing list
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