Raster Data in QGIS QGIS uses the GDAL library to read and write raster data formats , including Arc/Info Binary Grid, Arc/Info ASCII Grid , GeoTIFF , Erdas Imagine and many more. .
Raster Data in QGIS* More than 100 raster formats are supported by the GDAL library.* A complete list is available at http://www.gdal.org/formats_lis
Loading raster data in QGIS Raster layers are loaded either by click onLoad Raster icon OR by selecting => Layer=> Add Raster Layer
RASTER CALCULATORThe Raster Calculator in theLayer menu allows to performcalculations on basis of existingraster pixel values. The results arewritten to a new raster layer with aGDAL supported format
FIELD LISTThe Fields list contains all loadedraster layers that can be used. To adda raster to the raster calculatorexpression field, double click its namein the Fields list. You can then use theoperators to construct calculationexpressions or you can just type it intothe box.
RESULT LAYER In the Result layer section you have todefine an output layer. You can then definethe extent of the calculation area based on an input raster layer or based on X,Ycoordinates and on Columns and Rowsto set the resolution of the output layer.If the input layer has a different resolution,the values will be resampled with nearestneighbor algorithm.
OPERATORS SECTIONThe Operators section contains allusable operators. To add an operatorto the raster calculator expressionbox, click the appropriate button.Mathematical calculations ( + , - ,* . . . ) and trigonometric functions( sin, cos, tan, . . . ) are available.