Raster Conversion and Density Analysis

[MatthewFriesen]

Hello everyone;

This is the first time posting on this forum. I am interested in performing a conversion of polygon features to raster format. Features within the respective data are not important. What I am interested in is finding areas which overlap and areas that have higher amounts of layers that overlap to be verifiable. I will also be using polyline features and would like to add them to the output.

Will I have to convert all files to raster before performing the density analysis, and what would be the best method to perform this analysis. Thank you in advance.

[ShaunWalbridge]

Hi Matthew,

Perhaps the simplest approach is to convert the polygon layer into a 'count of overlaps' vector layer, and then rasterize that. There's a tool you can download to do it in one step, or follow the steps in this GIS.SE question to perform the same analysis. From there, you should be able to do a simple Polygon to Raster conversion. If you wanted to include polylines, just buffer them by a small distance to convert them to polygons prior to the 'count overlaps' step.

There are other approaches, like generating a fishnet and doing an intersect on your polygon data, but I think the above approach is simplest unless your data is large and complex.

cheers,
Shaun

[MatthewFriesen]

Thank you for the reply swalbridge. Does this tool allow for the use of weights involved with the vector layers? I have a weighting scheme implemented into the attribute tables of selected vector layers. This means some layers may be analysed in terms of how many times they overlap. Other layers must use the weights associated with the respective layers (ie: myLayer1 in AREA1 has a weight of .1 therefore if added to myLayer 2 with no weight (ie: does it overlap or not) in Area 1 will be 1.1).