In some projects that we have carried out we have had to represent the population by block. We had this population as street and number, in a point layer (very common in the census of inhabitants of any municipality). In this post we are going to explain how to use a pair of geoprocesses to have the population per block in an easy way.

Source data:

• A point layer that contains the population data by street and number.
• A polygon layer that represents blocks.

Once the layers are loaded on a View in gvSIG Desktop, we simply must run 2 geoprocesses:

• Snap points to layer. This geoprocess will move the points to the closest block edge. We can indicate a tolerance or distance from the point to the polygon, which points will be taken into account.
• In-polygon spatial join. For each polygon, it will count the values of the field of the point layer that contains the population data. That is, it will show us the total number of inhabitants per polygon.

Now we can work with population information by block.

In the following video you can see how to do it step by step: