I am new to QGIS. I have created tiff images from MODIS data using QGIS. I want to study the water flow/resources from those images. As I am new to this field I don't understand how to study those images. Please help me in this regard. Please provide me any suggestion, link or tutorial from where I can understand how to study those images for water flow or resources.

2 Answers 2


i think you should check out grass plugin for your study. it has lots of raster analysis as Hydrologic modeling toolbox. you can check out GRASS GIS 6.4.3svn Reference Manual here

Watershed modeling related modules are r.basins.fill, r.water.outlet, r.watershed, and r.terraflow. Water flow related modules are r.carve, r.drain, r.fill.dir, r.fillnulls, r.flow, and r.topidx. Flooding can be simulated with r.lake. Hydrologic simulation model are available as r.sim.sediment, r.sim.water, and r.topmodel.

  • r.flow - Construction of slope curves (flowlines), flowpath lengths, and flowline densities (upslope areas) from a raster digital elevation model (DEM).

  • r.watershed - Watershed basin analysis program.

  • r.water.outlet - Watershed basin creation program.

  • r.drain - Traces a flow through an elevation model on a raster map.

and getting some fundamental information you can glance at The GRASS GIS software (with QGIS) - GIS Seminar, here

i hope it helps you...


Also, an image is an optical view. If you are looking at doing watershed modeling, which it seems you are, then you will want to have elevation data (DEM) and an idea of where water sources are. Depending on where in the world you are looking to study, there are a number of DEM data sources available, at ranging resolutions, for free.

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