I am having hard times thinking how to create habitat quality risk rasters? Would anybody be willing to share step by step process to make at least 1 risk raster or some video tutorial on how to create those rasters? It would be very helpful for the beginners like me. Thanks in Advance.
Hi Jack -
It depends on what kind of threats you have. I’ll give couple of examples of threats that are commonly used, and an example of how you could create the raster from them. (There are undoubtedly other GIS paths for creating the raster too, I’ll just give one.)
Roads: Often, we have vector (line) road shapefiles, from governments, Open Street Map etc. To use them in Habitat Quality, you can add a field to the shapefile, giving all roads a value of 1 in that field. (Or, if you want to assign different threat weights to different types of road, you can assign values between 0 and 1 in this field.) Then convert the shapefile to raster, where the raster has the values from the field you created. Finally, use something like a Reclassify tool to change the background NoData values to 0, so you have pixels with a value of 1 where there are roads and values of 0 where there aren’t. You can do something similar for other types of vector data too such as points or polygons where there are towns.
Urban areas: These might come from a land use/land cover map, which are often already in raster format. If so, all you need to do is Reclassify Urban areas to a value of 1, and all other land use types to a value of 0. This can also apply to something like Agriculture, or any other relevant land cover type.
Does this help get you started?
Thanks for the so thorough answer. I can definately get started now. For roads, I can create a field and specify value ranging from 0.1-1 depending on highway or dirt road and so on then everythig within study area be 0. Similarly, how can i provide weights on urban areas? Is it a good idea that within land cover raster, everything except urban be 0?
Hi Jack -
For the model, we need to create a separate raster for each threat. So if your analysis is considering both urban and agricultural areas as threats, you’d provide one raster where urban areas have values > 0 and everything else has a value of 0, and a separate raster where agricultural areas have values > 0 and everything else has a value of 0. Then you’ll provide parameters for each of these threats separately in the threats table input, as described in the User Guide.
It is up to you to decide which threats to include, which will be based on things like which species (or groups of species) you’re modeling, what kind of infrastructure/activities are going on in your area of interest, and the reality of which data are available.