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Hi Cody B. You're right- "However, it sounds like you don't really need the slope raster, but ultimately only need the individual slope values sampled at points defined by an input shapefile. Your method for extracting samples should (?) work by inputting the layer into your "point slope extraction" tool. " I added the slope function to my raster layer and was able to extract those values to my point shapefile without saving the slope raster to my disk. Thanks so much for the help! That's definitely the fastest way to do this.
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11-30-2018
10:47 AM
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Right, that was what I tried first- the output tif in a regular folder, not in a .gdb.
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11-29-2018
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Hi Cody, I don't generally work with functions, but I'm under the impression that my slope map would be a sort of "on the fly" projection if I used the slope function. I need my output to be a new raster comprised of slope values, so that I can extract slope values at point locations that I read in using a shapefile. Is there a way to get a new raster file using the slope function? -Sky
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11-29-2018
04:43 PM
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Hi Dan, Thanks for the response! I have tried naming the output raster file as a .tif, I have tried naming it without a file extension, I have tried to specify the output raster path so that the raster file ends up in a .gdb, and I have tried routing the raster to a regular folder. None of the combinations have worked thus far.. The error is the 999999 Error Executing function.
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11-29-2018
04:24 PM
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This slope tool: Slope—Help | ArcGIS for Desktop is what I've been using on my regular raster TIFF files. However, I have a group of rasters that are File Geodatabase rasters, and the tool doesn't seem to work with them. I've tried both in the GUI and in ArcPy. The geodatabase rasters are about 13GB total, so converting them to regular TIFFS would be time and space consuming, and I'm not sure if that's actually possible.. I need to figure out how to use this slope tool with gdb rasters. Attached is my code, for reference. Any help is appreciated!
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11-29-2018
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Yes, thanks so much for your help with this. Glad to see it was so simple!
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11-26-2018
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Dan Patterson , Thanks for your reply. I copied my file to a geodatabase featureclass, but I'm still not sure how to nullify the -9999 values. I think it would be easiest to write a little python code to put in field calculator, that finds all of the -9999 and replaces them with null, so that I can average all of the columns and ignore the null values. Any help with this would be awesome!
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11-20-2018
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I am an ArcPy beginner, and I wrote a pretty clunky python script to populate a column of a point shapefile's attribute table with data from a slope map raster. Basically, it uses 'extract multi values to points' tool to find the slope of the raster at all of the points in my shapefile, and store those values in an attribute field. It looks like this: # Set points shapefile to populate with slope info, set input directory of slope raster inPointFeatures = "E:/ArcGis_Final_MHWLines_CenCal/2016/Cencal_2016_SD.shp/" inDEM_ = "E:/Lidar/LidarData_CenCal/C2016/C2016_slopes/Cencal_2016_02_slope.tif" print "input slope map is " + inDEM_ print "input shapefile is " + inPointFeatures # Execute ExtractValuesToPoints arcpy.gp.ExtractMultiValuesToPoints_sa(inPointFeatures, inDEM_, "NONE") I repeat that code for each slope raster. Unfortunately, when I ran that code for multiple rasters (and the same point shapefile) it created a new column for each raster. I wanted to merge all of these columns together to make one, neat column that stores all of the slope values and erases all of the -9999 values. And in the end, I just want an average of all of these values- just one final number. Is it possible to do this in ArcPy? Or with field calculator? I will have to do this multiple times (unless I can write a code to loop through my rasters and leave the slope value in one column.. so far this has been unsuccessful.) So I want to avoid exporting to MATLAB or Excel. Any tips are greatly appreciated!
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11-19-2018
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