raster statistics by line shape (vector)

Question

I have a georeferenced area where I created 7 raster maps (classified with suitability values from 1 to 5) as I have 7 factors to check e.g. natural reserves, floods, slopes etc. From there I did a weighted overlay raster for the final evaluation. In this area I have a railway corridor (represented by a line) which I buffer at 30 meters. I want to calculate a suitability score from the cells that this buffer contains. For example if the buffer contains 10 cells with value 1, 10 with 2, 20 with 3, 20 with 4 and 40 with 5, the final score will be: (10*1)+(10*2)+(20*3)+(20*4)+(40*5) = 370 points of suitability.

How can I count the number of cells from each value this buffer "touches" and the final sum? If in some way I could clip the raster with the buffer, the new raster of the buffer should contain "value" and "count" and I suppose I could do it from there. I don't know if I need to do the buffer or it can be done with the line shape, since the raster already contains cells of 30m*30m.

Answer 1

If you have the Spatial Analyst extension for ArcGIS, then you may consider this approach:

1. Convert your buffered polygons to a raster layer using the Polygon to Raster tool. The result will be a Boolean image of 1's and 0's, with cells with value 1 being within the buffered area.

2. Use the Combine tool to get the cell count for each class within the buffered area.

Other useful tools for summary statistics include Extract by Polygon and Zonal Statistics. Zonal Statistics will also require rasterization of the buffered area before use.