Latest Contributions by AustinMilt

Thanks for your reply. Can you explain what the statement means? Does it mean that the result is half as big as expected, or that the volumes for all pixels along one side are half as big, or that volumes for all pixels along the border are half as big, or that the result will be off for one pixel? The statement in the documentation, while pointing to one reason why I might have different results, still obscures how one would go about calculating surface volume using their technique, and thus from understanding how I should specify inputs to the tool. ... View more

I created a toy raster with the following values: 30 30 30 30 30  0   0  30 30  0   0  30 30 30 30 30 and a projection of NAD_1983_Albers, with 30x30 m cells (to match my DEM motivating the issue). I then ran Surface Volume (3D) with the following settings: Reference Plane: BELOW Plane Height: 30 Z Factor: 0.01 **Note I was not allowed to change this value in ArcMap; it was interpreted by default from the projection. Based on my multiple open topics, here are results I could expect given those inputs: plane height is in meters, z factor is m/cm: volume = (30 m)*(30 m)*(30 m)*(4 cells) + (30 m)*(30 m)*(29.7 m)*(12 cells) = 428,760 m^3 plane height is in centimeters, z factor is m/cm: volume = (30 m)*(30 m)*(0.3 m)*(4 cells) = 1,080 m^3 plane height is in meters, z factor is in cm/m: volume = (30 m)*(30 m)*(30 m)*(4 cells) = 108,000 m^3 plane height is in centimeters, z factor is in cm/m: volume = (30 m)*(30 m)*(0.3 m)*(4 cells) = 1,080 m^3 The actual results are... 241,650 somethings^3.  My conclusion: either I dont understand what this tool is doing (and my topics asking for more explanation are well-founded), my experiment was flawed, or there's something very wrong with the tool. If anyone can shed some light on the topic, I would be really appreciative. ... View more

Thanks for your reply Dan. That suggestion in the last link was my own, and unfortunately it's just a guess. My hope in creating a separate topic was to put this thing to rest with a definitive answer from someone with extensive experience with the tool or direct knowledge of the programming. Perhaps, as you suggest, I should just go create a toy raster with known units and experiment, though it would be much more satisfying to get it directly from the horse's mouth (as they say). ... View more

Thanks for your prompt reply Darren. I understand when to change the z-factor, but my question is about what a change in the z-factor does to the output volume units. In my case, I'm working with a DEM that has units of m x m x cm (the standard format for NED DEMs), so I think I specify a z-factor of 0.01 m/cm (though now your answer confuses me about the appropriate value). Assuming that's all correct, my question is: Is the output volume measure in units of cubic meters, or cubic centimeters? I had assumed it would be cubic meters, but the values seem way too large to be correct, and dividing by 1e6 cm3/m3 seems to make them more reasonable. ... View more

Gerry, could you expand on this a bit. If you changed the z-factor, will the output units be in the z units rather than the xy units? The tool documentation is ambiguous, but led me to believe the volume would always be in the xy units (the only evidence is the statement "This is typically used to convert Z linear units to match XY linear units."). ... View more

Please post the top portion of your code where you parse out the input parameters. Sorry, which part are you talking about? The execute() method? # ~~ execute() ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #     def execute(self, P, messages):         """         EXECUTE() calls ImpactScoreRasters.ImpactScoreRasters in Bungee's         executing directory.         """         pK = self.paramOrder         import arcpy                 # process parameters         analysis = arcpy.Describe(P[pK['analysis']].value).catalogPath         outPad = arcpy.Describe(P[pK['outPad']].value).catalogPath         outRoad = arcpy.Describe(P[pK['outRoad']].value).catalogPath         outPipe = arcpy.Describe(P[pK['outPipe']].value).catalogPath         usePadFootprint = P[pK['usePadFootprint']].value Or are you referring to the getParameterInfo portion?     # ~~ __getParameterInfo__() ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #     def getParameterInfo(self):         """Define parameter definitions"""                 import arcpy                 # input analysis object (pickled file)         analysis = arcpy.Parameter(             displayName = 'Analysis Object File',             name = 'analysis',             datatype = 'File',             parameterType = 'Required',             direction = 'Input'         )                     # Output Pad Raster         outPad = arcpy.Parameter(             displayName = 'Output Pad Raster',             name = 'outPad',             datatype= 'Raster Dataset',             parameterType = 'Required',             direction = 'Output'         )                 # Output Road Raster         outRoad = arcpy.Parameter(             displayName = 'Output Road Raster',             name = 'outRoad',             datatype= 'Raster Dataset',             parameterType = 'Required',             direction = 'Output'         )                 # Output Pipe Raster         outPipe = arcpy.Parameter(             displayName = 'Output Pipeline Raster',             name = 'outPipe',             datatype= 'Raster Dataset',             parameterType = 'Required',             direction = 'Output'         )                 # Use Pad Footprint Flag         usePadFootprint = arcpy.Parameter(             displayName = 'Use Pad Footprint?',             name = 'usePadFootprint',             datatype = 'Boolean',             parameterType = 'Optional',             direction = 'Input'         )                 usePadFootprint.value = False         # finish         parameters = [             analysis,             outPad,             outRoad,             outPipe,             usePadFootprint         ]         return parameters ... View more

Austin, I've submitted a bug report on this issue. cheers, Shaun Thanks. Is there a way for me to do this in the future, or is it best for me to submit to the forum for all the world to see? ... View more

Austin, I don't think there's any way of doing this built-in, but you could add an idea or an enhancement request if you think this behavior would be useful. I could imagine something like a new attribute in a tool's init method which referenced another location. I generally am managing the .pyt.xml files in Git, and only use git's status to look at my directories, so don't usually see the documentation files directly. cheers, Shaun How would I submit an enhancement request? ... View more