I am adding here the image, actually i have to calculate the total value of the variable stored in the .tif tile for the boundary closed by blue lines, i have several these type of polygons, here in the .tif file Evapotranspiration data is stored, i have to calculate the total value of evapotranspiration for the area closed by blue boundary (Sub-basin), every area is consists of lots of pixels of .tif file. How it can be done in GIS or any other image processing software?
it can be done by calculating area of watershed on the map using either planimeter or ArcGis and then dividing total area by area of each grid (Polygon).
http://gis.stackexchange.com/questions/80232/calculate-area-covered-by-a-particular-raster-layer-within-polygons-in-qgis
http://www.qgistutorials.com/en/docs/sampling_raster_data.html
Dear Rajat Kr Sharma,
You can use the mask tool in ArcGIS and take out the required area. Then the calculation will be easier. Please check the link below. Hope it helps.
with regards,
Hari
http://www.derivativesinvesting.net/article/596690003/tutorial-arcgis-10-1-how-to-extract-by-mask-spatial-analysis-/
If ArcGis is not available for you, you can do using R (packages raster and maptools)
Thanks to all. In zonal statistics tool..it can be done very easily, somebody told me about it.
Hi Rajat, You have multiple options:
Of course there are open source options using Python, R etc.
Use R is one of the best options to work with Raster Data and Calculate Statistics
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