Markus Neteler wrote:
> > Remember that you have to rescale these data first:
> >
> > https://lpdaac.usgs.gov/lpdaac/products/modis_products_table
> > -> MOD09Q1 Terra
> Surface Reflectance Bands 1–2
> Tile 250m
> 8 Day
> >
> > https://lpdaac.usgs.gov/lpdaac/products/modis_products_table/surface_reflectance/8_day_l3_global_250m/v5/terra
> > -> layers
> >
> > ... MULTIPLY BY SCALE FACTOR ...
Nikos wrote:
> Yep, I know that. But why is it wrong to just use them as they are?
FWIW, the MODIS/Aqua Chlorophyll-a product requires more than simple
linear rescaling:
r.mapcalc "${map}.chlor_A = 10^(($Slope * $map) + $Intercept)"
http://grass.osgeo.org/wiki/MODIS#Processing_2
so you may need to take care if working directly with raw 0-65535 data.
Hamish
_______________________________________________
grass-stats mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/grass-stats
