Latest Contributions by MarkEllis

Your example of distribution of gas escapes would fit raster analysis well.  Many of the spatial analyst tools could be put to use - distance, density, amounts, proximity, etc. ... View more

I recall spatial analyst having some functions that would do this - NEAREST or some such.  Output cells contain the linear distance from the cell to whatever feature is being analyzed. This could then give you the values at the points you seek. ... View more

If you have Adobe Acrobat, add a link to the pdf output to open the new maps.  Far from automated, but gets the task done. ... View more

You cannot just remove cells from a raster.  The equivalent would be to change the value of random cells to NODATA (or zero, as needed).  To do this, you could create a random point layer, then convert this to raster.  Once a raster, reclassify the cells to whatever value will delete the vegetation values. Make sure your other cells have some other value to keep them apart, of course.  Do you have Spatial Analyst?  If so, the Set Null function can be used to replace cell values where a condition is met, e.g. where your random points lie.  Use this to change your vegetation cell values accordingly. ... View more

What license do you use? ... View more

Just posted the following in another thread a few days ago, see if it solves your problem: First, confirm that there is no gap in the source imagery. If at least one raster has a value where the output shows NODATA, it might be a matter of setting parameters in the tool. The last two optional parameters are Mosaic Operator and Mosaic Colormap Mode. The default for the former is LAST, which gives the output the value of the last source raster that overlaps that cell. If this is NODATA, that will appear in the output. By changing this to MAXIMUM (or whatever suits your data best), NODATA values will be overridden by actual values in the output. The same idea holds for the Mosaic Colormap Mode, but with options for a colormap instead of cell values. ... View more

Unless you have a good match between layers (similar number of features with similar locations), Spatial Join is likely the tool to use. We were able to use this with point features by running multiple spatial joins - first run for close proximity; second run with a larger search distance; so on as the data needed. Between each run, calculate the attributes for those with matches and flag them to mark both that it is done and the quality of the match. Repeat, but query out those features already done, as necessary. Our layers were geocoded points matched to inconsistent, inaccurate general locations based on PLSS data. Because many points matched multiple others, running through the batch manually ended up a part of the task. Though this is indeed time consuming, it resulted in a rather accurate layer. ... View more

First, confirm that there is no gap in the source imagery.  If at least one raster has a value where the output shows NODATA, it might be a matter of setting parameters in the tool. The last two optional parameters are Mosaic Operator and Mosaic Colormap Mode. The default for the former is LAST, which gives the output the value of the last source raster that overlaps that cell. If this is NODATA, that will appear in the output. By changing this to MAXIMUM (or whatever suits your data best), NODATA values will be overridden by actual values in the output. The same idea holds for the Mosaic Colormap Mode, but with options for a colormap instead of cell values. ... View more

In case you are not already familiar with the background of the ArcGIS tools, they are covered in a white paper: http://proceedings.esri.com/library/userconf/proc99/proceed/papers/pap867/p867.htm I've not used these tools in a long time, so will not hazard a guess about what might explain the differences you see.  Hopefully the paper will provide something to trigger an idea... Good luck! How many of the optional parameters did you use in the process, and did the 'other source' results use the same set of variables? ... View more

I just figured out a way to do this using an unmanaged raster catalog. As stated in the earlier replies, create a symbology (e.g. a color map) that will cover all possible values. Use a script to apply this to all the rasters. It can take a long time, but can run in the background while you get other things done. I used the following simple script to apply a color map to a zillion grids within a workspace. Modify as needed: ## Add color map to DRGs ##==================================== import arcpy from arcpy import env # Set workspace arcpy.env.workspace = "C:/your_path_here" # Get list of grids rasterList = arcpy.ListRasters("*", "All") for raster in rasterList:             # Assign colormap using clr file        arcpy.AddColormap_management(raster, "#", "your_symbology_file.clr") ... View more

Do you have the option to create a grid (based on the kriging grid cells) version of the polygon layer? This way, polygons too small for extractign would be expanded to fit the cells you wish to grab. ... View more

Thanks for the tip!  I also noted in documentation that the workspace path should contain / instead of \, as the latter is a line continuation character in python.  The two changes together worked, it is now running. Syntax is tricky for the beginner... ... View more

Do you mean to have a text label move with a feature to its new location when editing? Simply having a text string as your label should do this. Toggle labels off or on as needed. Or are your text strings something not in the data? Have you worked with feature-linked annotation? ... View more

Reposted script with code tags... ## Add color map to DRGs ##==================================== import arcpy from arcpy import env # Set workspace arcpy.env.workspace = "Y:\base_data\State\IL\100k_DRGs" # Get list of grids rasterList = arcpy.ListRasters("*", "GRID")    for raster in rasterList:       ## Add Colormap       try:                ##Assign colormap using clr file           arcpy.AddColormap_management(raster, "#", "ISA_DRG.clr")           print raster       except:           print "Add Colormap example failed."           print arcpy.GetMessages() ... View more

Going through the python window in ArcMap has only made this more confusing. Going line by line, there are no errors until the 'for raster in rasterList' line - F2 returns a parsing error "expected an indented block" Edit script or clear and reload with an indent, F2 returns a parsing error "unexpected indent" Really? How does one fix this? The Help documentation is worthless for details like this, any guidance from a user would be appreciated. ... View more