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I have a raster file about land usage in northern italy (crops / urban areas ecc..)

I have defined some buffer zones around some given points of a vector layer and I'd like to calculate the % of those areas occupied by each value of the raster file in order to make an estimate on the average usages of the selected areas (like 70% crops, 30% urban, etc..).

I know that in ArcGIS there is a Spatial Analyst function to do so called "Tabulate Area", but I can't find such feature in QGIS.

If anyone can help me I'd be so grateful.

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Ricardo, welcome to our site! I wonder whether you meant to write "QGIS" instead of "ArcGIS" the second time, so that perhaps your remark should read, "I know that in ArcGIS there is a function ... but I can't find such a feature in QGIS." – whuber♦ Apr 12 '12 at 13:58
I went ahead and edited the question text. Please revert it if I've misinterpreted your question. – underdark♦ Apr 12 '12 at 18:09
@underdark Thanks dude, yes that is what i ment, was a mistype. – Riccardo Apr 13 '12 at 9:50
@whuber Thanks for reporting the mistake, but i still didnt solve my problem =) Its weird because its a very simple task and im confident there is a feature for it. – Riccardo Apr 13 '12 at 9:52

3 Answers

up vote 1 down vote

try to use "Cross-Classification and Tabulation" of SAGA GIS from Sextante plugin.

Hope this help

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Which you must first install via the plugin manager (Fetch python plugins), unless you are using a selfcompiled version — it was added to core after 1.8.0. – lynxlynxlynx Nov 30 '12 at 9:36
up vote 0 down vote

I've coded a Plugin for QGIS called LecoS (look in the Plugin Downloader, experimental plugins, install Scipy first! ). It can achieve what you want (percentages of land cover for a given raster), however until now i haven't found the time to code a polygon overlay in python and therefore you have to clip your raster individually per buffer and vector feature beforehand. See a usecase here.

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up vote -1 down vote

Tabulated Areas tool is located in the Spatial Analyst toolbox in the Zonal tools section for ArcGIS 10. Not sure what version you are running. Note that you have to have a separate license for Spatial Analyst extension to use those tools. Sounds like that tool will do what your looking for tho.

Hope This Helps

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Thanks for the answer dude, i know where the tool is located in arcgis, i suppose you answered this way because of my error in typing the question. I'm looking for a similar tool in QGIS. – Riccardo Apr 13 '12 at 9:49

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