SAGA, GRASS Raster values to null

Question

I want to make the cells which values "1" to null in QGIS with Grass or Saga tools (exactly Saga).

Answer 1

Thanks to Volker Wichmann from SAGA GIS forums. If you want to change the cell values to null you can use Saga reclassify grid values from Sextante. Enter the -99999 which will be null on the option for new values for other values. Saga accepts -99999 value as NoData.

Answer 2

In GRASS GIS (hence, in QGIS via GRASS toolbox or Sextante-GRASS plugin), use r.null to set selected values to NULL. Any cell value may be turned into NULL.