Quantum GIS - Union polygon layers, then derive summary statistics in MS Excel.

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This video shows how to employ the UNION vector geoprocessing function in Quantum GIS to analyse the relationship between two overlapping polygon GIS layers, creating some summary statistics as output. This video uses the example of two separate polygon GIS layers. 'Layer 1' contains planning zones identified as "Zone 1", "Zone 2" and "Zone 3". The second GIS layer ('Layer 2') contains crop types... "Wheat", "Rice", "Barley" and "Oats". Layer 1 (planning zones) and Layer 2 (crops) overlap each other. The question that this analysis seeks to answer is "What is the total area of each crop type, falling within each planning zone". The UNION vector geoprocessing function is used to combine the geometry and attributes of the overlapping GIS layers, before Microsoft Excel is put into action to create a summary table (ie. a Pivot table) that gives us the answer to our question.