[GRASS-dev] image processing modules for GRASS GIS

Yann yann.chemin at gmail.com
Fri May 18 16:39:29 EDT 2007

Hi all,

There is a group of modules about satellite image processing in the GRASSSVN 
Add-ons repository that I am working on. Today, i've been suggested to write 
this email.

I would like to ask whether some people would be interested in expanding the 
standard raster menu of GRASS with some of these modules contained in this 
set. A large part is composed of r.eb.* modules, dedicated to energy balance 
calculations ultimately leading to Actual evapotranspiration estimations.

Already i.atcorr was in GRASS 5.x, and there were interests to return it into 


Additional info below:

This is a Brief ID card 
Name: GIPE, the GRASS Image Processing Environment.

Objective: To group a set of modules aiming at processing some common 
satellite imagery from Digital Number up to some high level products that may 
be useful on their own. A clear interest is in the many modules of 
Evapotranspiration (ET: mm/day), but some others are there too (biomass, 
Vegetation Indices, Albedo, etc).
Number of modules: 33 so far (+2 from other authors: h.evapo.PM and i.atcorr)

The list of modules
- i.atcorr: 6s atmospheric correction model wrapper, ported to 6.x cvs, 
including needed code cleaning
- h.evapo.PM: renamed r.evapo.PM, Potential ET after Penman and Monteith

- r.dn2ref.l7: convert DN to radiance and/or reflectance for Landsat 7 
- r.dn2full.l7: use .met file to convert all automatically into reflectance 
(including temperature radiance for temperature bands)
- r.dn2ref.ast: convert DN to radiance and/or reflectance for Terra Aster ( 9 

- r.vi: 13 types of vegetation indices (mpi and Ninf/G grid versions for 
educational purposes)
- r.albedo: input to r.sun, calculates Albedo from NOAA AVHRR, MODIS, Landsat 
and Aster.

- r.latitude: calculates a latitude map (degrees)
- r.sunh: calculates potential sunshine hours
- r.sath: calculates the satellite overpass time

- r.evapo.MH: Reference ET after Hargreaves and Modified Hargreaves
- r.evapo.PT: Potential ET after Prestley and Taylor
- r.evapo.potrad: Potential ET from Net radiation
- r.dn2potrad.l7: use .met file of Landsat 7 to calculate potential ET 
directly from Digital Numbers.

- r.eb.eta: ET calculation after SEBAL
- r.eb.z0m: surface roughness estimation
- r.eb.deltat: difference air-surface temperature
- r.eb.netrad: net radiation
- r.eb.disp: displacement height
- r.eb.molength: Monin-Obukov Length
- r.eb.psi: Psichrometric parameters for heat 
- r.eb.ublend: blending height wind speed 
- r.eb.ustar: nominal wind speed
- r.eb.rah: aerodynamic resistance to heat transport
- r.eb.g0: soil heat flux
- r.eb.h0: sensible heat flux
- r.eb.h_iter: sensible heat flux with iterative adjustment of some parameters
- r.eb.evapfr: evaporative fraction calculation and soil moisture estimation

- r.biomass: Calculate biomass growth of a plant (main input to yield 

(these are not image processing directly, but they got created on some job so 
i keep them in the same place)
- r.uslek: Calculates the USLE K factor from percentage of sand, loam, clay 
and organic matter.
- r.usler: Calculates USLE R factor from any one of 4 different standard 

Yann Chemin
Sainte-Anne d'Auray, France

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