[GRASS-user] Ussage of new i.* modules in Grass70

Dear GRASS community,

Hello, I am thrilled to find a number of promising modules under ‘imagery’ incorporated in the standard GRASS70 version. Specifically the “evapotranspiration calculation” modules have our special interest. Weren’t they before addons?

However I have some troubles to go through the complete calculation. The explanations on the manual pages are very (too) basic. For example, I got stuck at the “sensible heat flux calculation” that demands the “aerodynamic resistance to the heat momentum”. I supposed an average value that I found on the web and created with r.mapcalc a raster with that value. But finally I got a raster with only 0 values.
Would it be possible to create a Wiki for this evaporation module with some examples? Or could someone direct me where I can get detailed advice?

Thanks,

Huub

Huub Munstege
Bamako
Rép. du Mali


On Thu, Jun 11, 2015 at 10:01 AM, Huub Munstege <hmunstege@yahoo.com> wrote:

Dear GRASS community,

Hello, I am thrilled to find a number of promising modules under 'imagery'
incorporated in the standard GRASS70 version. Specifically the
"evapotranspiration calculation" modules have our special interest. Weren't
they before addons?

Yes, that is right.

However I have some troubles to go through the complete calculation. The
explanations on the manual pages are very (too) basic.

Agreed - we hope to find volunteers to contribute. But there is a
starter which may be helpful for you:

Evapotranspiration mapping with Landsat 5TM in GRASS GIS
https://svn.osgeo.org/grass/grass-promo/tutorials/grass_landsat_ETa/main_document.pdf

For example, I got
stuck at the "sensible heat flux calculation" that demands the "aerodynamic
resistance to the heat momentum". I supposed an average value that I found
on the web and created with r.mapcalc a raster with that value. But finally
I got a raster with only 0 values.
Would it be possible to create a Wiki for this evaporation module with some
examples? Or could someone direct me where I can get detailed advice?

A wiki page would be excellent. Feel free to generate it, it is a
community wiki.
Searching, I just found this stub page:

http://grasswiki.osgeo.org/wiki/Image_processing/Evapotranspiration

Maybe a good starting point for further editing.

Best
Markus

--
http://courses.neteler.org/blog
http://gis.cri.fmach.it/neteler/

Thanks,

Huub

Huub Munstege
Bamako
Rép. du Mali

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Hi,

i.eb.z0m is producing an estimation of the surface roughness accordingly to the requirement, unfortunately, I did not have time to move it to the main trunk, would that be of interest?

Cheers,

Yann

On Thu, Jun 11, 2015 at 2:07 PM Markus Neteler <neteler@osgeo.org> wrote:

On Thu, Jun 11, 2015 at 10:01 AM, Huub Munstege <hmunstege@yahoo.com> wrote:

Dear GRASS community,

Hello, I am thrilled to find a number of promising modules under ‘imagery’
incorporated in the standard GRASS70 version. Specifically the
“evapotranspiration calculation” modules have our special interest. Weren’t
they before addons?

Yes, that is right.

However I have some troubles to go through the complete calculation. The
explanations on the manual pages are very (too) basic.

Agreed - we hope to find volunteers to contribute. But there is a
starter which may be helpful for you:

Evapotranspiration mapping with Landsat 5TM in GRASS GIS
https://svn.osgeo.org/grass/grass-promo/tutorials/grass_landsat_ETa/main_document.pdf

For example, I got
stuck at the “sensible heat flux calculation” that demands the “aerodynamic
resistance to the heat momentum”. I supposed an average value that I found
on the web and created with r.mapcalc a raster with that value. But finally
I got a raster with only 0 values.
Would it be possible to create a Wiki for this evaporation module with some
examples? Or could someone direct me where I can get detailed advice?

A wiki page would be excellent. Feel free to generate it, it is a
community wiki.
Searching, I just found this stub page:

http://grasswiki.osgeo.org/wiki/Image_processing/Evapotranspiration

Maybe a good starting point for further editing.

Best
Markus


http://courses.neteler.org/blog
http://gis.cri.fmach.it/neteler/

Thanks,

Huub

Huub Munstege
Bamako
Rép. du Mali


grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

On Fri, Jun 12, 2015 at 8:12 AM, Yann Chemin <ychemin@gmail.com> wrote:

Hi,

i.eb.z0m is producing an estimation of the surface roughness accordingly to
the requirement, unfortunately, I did not have time to move it to the main
trunk, would that be of interest?

At time I see it only as an Addon for GRASS GIS 6:

grass-addons/grass6/imagery/gipe/i.eb.z0m

It would be perfect to have it as an Addon for GRASS GIS 7 for now.

best
Markus

On Fri, Jun 12, 2015 at 8:54 AM, Markus Neteler <neteler@osgeo.org> wrote:

On Fri, Jun 12, 2015 at 8:12 AM, Yann Chemin <ychemin@gmail.com> wrote:

Hi,

i.eb.z0m is producing an estimation of the surface roughness accordingly to
the requirement, unfortunately, I did not have time to move it to the main
trunk, would that be of interest?

At time I see it only as an Addon for GRASS GIS 6:
grass-addons/grass6/imagery/gipe/i.eb.z0m

Sorry for the confusion (too early here to read :-), it is already there!

grass-addons/grass7/imagery/i.eb.z0m

Huub: you can install it with

g.extension i.eb.z0m

(or via the Addon extension manager in the graphical user interface)

Markus