Latest Contributions by EricRice

Greetings, You can do this using the Lookup tool available with spatial analyst or 3d analyst. Regards, Eric ... View more

Hi Graham, Thanks for the info. It's very helpful, and we'll get you situated in no time at all.  First though, I'd like to point you to some more reading. Why does my hillshade look different when I use a tool vs. a function? Given the information in the link, and the extent at which you want the hillshade to look good (zoomed out), I am going to recommend you use the Mosaic Dataset option and work with the Hillshade Function, rather than the Hillshade GP tool.  We already know the tool result looks good when zoomed in.  The display at smaller scales is less appealing because the Hillshade tool is applied at the source pixel size of the data, then resampled when you zoom out.  For this reason, the Mosaic Dataset is better because the Hillshade function is applied at the scale in which you are viewing the imagery, first resampling the DEM to that resolution before applying the hillshade effect. Forget the mosaic's you've created so far and only work with the original source tiles in WGS_1984.  I assume you are working with 90m SRTM data given your cell size of  0.00083333333.  Your X,Y units are therefore Decimal Degrees.  The Z unit I asked about was asking what units the elevation values were in.  I'll assume elevation is expressed in meters. Workflow: Create a geodatabase and a mosaic dataset.  When you create the MD, set the coordinate system to ED_1950_UTM_Zone_30N or WGS_1984_UTM_Zone_30N if you want to avoid setting a geographic transformation later.  Use ED_1950 if you require it.  By setting the coordinate system of the MD to something that uses meters for X and Y units, you are assuring that X,Y,Z are all in meters, simplifying the Z factor decision later. You'll just use a value of 1. Run Add Rasters to Mosaic Dataset tool.  Use Raster Dataset for the Raster Type parameter.  Point to the original data or the workspace where they all reside - your choice.  Load the data with UNC paths rather than C:\ or some other mapped drive letter if you plan on others accessing the data.  Check the box to "Update Overviews".  This is how you avoid seeing the gray box at small scales.  If the Mosaic Dataset is lacking statistics at this point, do not bother building them because they will only be invalidated after applying the function. Add Hillshade function In the Catalog window, right click the MD and click Properties. Click the Functions tab. Right-click the Mosaic Function and click Insert > Hillshade Function. Adjust parameters to your liking.  Z factor should be 1. Click the Defaults tab when you're done with the Functions tab.  Set the Default Resampling Method to Bilinear Interpolation. Also on the Defaults tab you can set the Geographic Coordinate System Transformation if you do use ED_1950. The statistics of the mosaic dataset are invalid since the original statistics were calculated on the elevation data (signed 16 bit data) and the hillshade is producing a 8-bit image. The last step is to recalculate the stats.  In the Catalog window, right-click the mosaic dataset and click Calculate Statistics.  When calculating the statistics for the mosaic dataset, you do not need to calculate them for every pixel. It is highly recommended you specify a skip factor. A simple equation is the number of columns divided by 1,000.  If you don't specify a skip factor, this process could take a very long time. View the mosaic dataset in ArcMap and let me know what you think at varying scales. Regards, Eric ... View more

Greetings, You can do this by embedding an IsNull statement within a Con statement. Con(IsNull("raster"),0, "raster") You may find these resources useful. How to add different-sized rasters with NoData Values  Raster Extents + Calculator Problems Best Regards, Eric ... View more

Hi Al, It sounds like you have SRTM 90 m data, which typically comes in a geographic coordinate system (WGS_1984) having a resolution of 0.00083333333 decimal degrees.  If you truly want your data to have units of meters you need to run Project Raster and specify a coordinate system that uses meters.  Then you specify 250 for output cell size.  Please be sure to set your resampling technique in the tool to Bilinear since the default is Nearest (which you don't want). Best Regards, Eric ... View more

Greetings, The input needs to be 1 or more layer files (.lyr), which store the 3D rendering properties. Regards, Eric ... View more