Latest Contributions by curtisbattle

I'm looking to calculate focal statistics for each cell of a raster, within a neighborhood that changes shape. Background - I have three binary rasters, each representing a single vegetation type of interest. I'd like to calculate the percent coverage of each vegetation type within (e.g.) 20 km^2 of any cell in my study area (sum/total cells in neighborhood). The problem is that I can't use a simple circle or square neighborhood around each cell because, if I did, the search area used to calculate the sum would incorporate areas outside my study area. This exception is important because the statistics will be used as inputs for a habitat model, and the areas outside of my study area cannot be considered possible habitat - they're urbanized. Including them would give me erroneous statistics. So, what I'm looking to do is come up with a way to choose a neighborhood representing the n nearest cells (n determined by number of cells required to cover an area equal to my desired neighborhood size) that meet my criteria: that they do not fall within an urbanized area. I'm thinking that some code that mimics cellular automata neighborhood decisions should be used. I've never worked with CA though. Example - Let's say I'm calculating this statistic for a cell on the boundary of my study site. If I assign all areas outside of my study area to zero (or ignore NoData), then I will get a statistic that represents roughly half of the areal coverage I'm interested in. So, percent coverage in a ~10 km^2 area, instead of 20 km^2 area. Since I'm studying home range sizes this is important. The neighborhood has to change shape, since that is how the animal views/uses the landscape. If they need 20 km^2, they'll change the shape or their home territory so that in encompasses 20 km^2. If I do not check ignore NoData, cell output will be NoData - and NoData is no help. Any ideas? ... View more

Hi All - I have an issue that has been nagging me forever. Here's an example. I have a layer in a map, and under Properties > Source it shows "Projected Coordinate System: NAD_1983_UTM_Zone_11N" and "Geographic Coordinate System: GCS_North_American_1983". My first question is: am I working with a projected, or a geographic coordinate system? Second: what is NAD 83? Third: is UTM a projected or geographic coordinate system? I'm so freaking confused! The more I look into it the less clear it becomes! Lastly, when I open the attribute table, create a new field, field type double, etc... calculate geometry the only option I have is to calculate "X coordinate of point" or "Y coordinate of point". Why can't I calculate lat/long in minutes, seconds, etc? What if I wan't both in the same attribute table? I'm thinking the answers to the first set of questions are huge, and that I know so little about it that I don't even really know how to ask the question. Any help would be greatly appreciated! ... View more