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How to calculate number of raster files in R?
I am assuming that you want the sum of the cells that are not NA. If you actually have rasters with a different origin/resolution, you can repeat these steps, but there no need to stack them into a RasterStack, but you would need to adjust the approach to also count the NA cells.
How to count points in polygons with R?
I’m quite new to R and especially GIS with R. So recently I had to proceed to a quite simple analysis: counting health centers (points) per administrative unit (polygons).
Is the number of cells the same for all rasters?
The number of cells (pixels) would be the same for all rasters if you can stack them (which you say you can). I am assuming that you want the sum of the cells that are not NA.
How to add attributes to a point layer?
Use the “Join Attributes” tool from the Vector -> Data Management menu. Select an attribute of your point layer (this could be a simple column representing TRUE (1) or FALSE (0) values for different conflict events). Select your grid and Sum all occurrences and execute.
How to calculate raster statistics for polygons?
I tried that with QGIS first. There is a way to do it but that is much too slow (convert raster to vector, intersect with second vector-layer, calculate geometry, export numbers, calculate statistics with spreadsheet or other program, re-import the results, takes forever for my 350.000 raster-points). I was also given the hint to use saga-gis.
Can you get raster statistics for only one band?
You get stats, yes, but only for the first band in a raster. So if you operate with a 3-band raster image, the stats are incomplete. I should have pointed out the number of channels in my original post. Best to use SAGA-GIS like stn proposed above if your working with multi band raster images.
Can a zone raster conform to a polygon?
The raster will never conform to the shape of the polygon but it will assign values to the zone raster based on the values of the cells using the zone that contains the “majority” of a cell. Since your raster is what it is and your polygon is what it is, this is really the best you can do.
How do you count cells within a polygon?
The method will count cells within the polygon that includes most of the cell (to answer your question in item 1. Use the Zonal Statistics As Table Tool with the polygon layer as your zone (select a field that uniquely identifies each polygon as the zone field).