Latest Contributions by EricRice

Rob, The polygons are converted to rasters anyway, so I would just convert and skip checking the geometry.  Only check the geometry if you can't convert the zones into a raster dataset.  When you convert, set the cellsize equal or smaller than the resolution of your landuse data and be sure to set the conversion output to be snapped to the landuse raster. Eric ... View more

I pulled this directly from the Slice tool documentation under Usage. "When using the EQUAL_AREA method, sometimes not all of the output zones  (classes) will have an equal, or even similar, number of cells (i.e.,  area). This may be an inherent result based on the nature of the input  values and the specified number of zones. If the results are deemed  undesirable, you can try using a fewer number of zones or applying a  statistics transformation (e.g., logarithm, square root, and so on) to  the input dataset." Best, Eric ... View more

The zones are counties Jeff, and there isn't a state in the union with more counties than the maximum unique values to render so it should be building a table during the conversion.  At this point, I would suggest Rob contact Esri Support and have an analyst go through it with him.  Rob posted this same question to the GP forum but included more details in that thread, specifically about the background gp process failing with error messages.  The first test is obviously running it in the foreground to narrow the issue down. After that, I would do what you suggested and convert the zones into raster datasets and run it again, to narrow down the issue some more. Support will know what to do in terms of other troubleshooting. Best, Eric ... View more

Hi guys, The graphic is wrong and I've talked to the tool owner to have him update it.  The tool, however, seems to be working as it should. See screenshot attached.  I'm using 10.1 sp1 for this test. Best, Eric ... View more

If you have a wetland polygon you can use it as a zone in the Zonal Statistics as Table tool, which would give you the mean value (among other statistics) from the NDVI layer you created. Best, Eric ... View more

But everything I have read about the NDVI's says that the resulting calculations should be in a range from -1.0 to +1.0 with negative number signifying vegetation loss and the positive values signifying vegetation gain. I suppose if you differenced two NDVI's you can tell if you lost or gained vegetation, but the index itself doesn't tell you this.  Below is an excerpt from our documenation. "This index outputs values between -1.0 and 1.0, mostly representing  greenness, where any negative values are mainly generated from clouds,  water, and snow, and values near zero are mainly generated from rock and  bare soil. Very low values of NDVI (0.1 and below) correspond to barren  areas of rock, sand, or snow. Moderate values represent shrub and  grassland (0.2 to 0.3), while high values indicate temperate and  tropical rainforests (0.6 to 0.8)" Best, Eric ... View more

Sorry, I assumed you were using 10.1.  In 10.0 that option did not exist. In 10.0 you will have to use the raster calculator and the appropriate band math to arrive at a floating point raster between -1.0 - 1.0. NDVI = ((IR - R)/(IR + R)) Best, Eric ... View more

Hi Laura, On the IAW options dialog there is an NDVI tab.  Check the box that says, "Scientific Output".  This will give you the values you are looking for.  Best, Eric ... View more

You cannot drape imagery onto contour lines.  You need a surface to drape on.  You can interpolate a surface using contour line input with Topo to Raster.  I do not recommend working with undefined data. ArcScene bases its z units on the x,y units from the defined projection.  Data should be projected before using in ArcScene. Best, Eric ... View more

You're probably displaying the raster with a stretched renderer.  Switch it to unique values then run Zonal Histogram. Usage Tip from tool documentation that I believe applies here:   "In the histogram graph, the number of classes (bins) for each zone is determined by the Input value raster.  If a layer is specified, then the layer's symbology defines the number of classes.     If a dataset is specified,  by default there will be 256 classes,  unless the input is integer with less than 26 unique values, in which  case it will be the total count of unique values." The graph is based on the table, so maybe we need to reword that a little. Best, Eric ... View more

You can do a spatial join and sum the points that fall inside the polygons.  The sum field will be added automatically.  You could also convert points to raster (where output raster is same resolution of your fishnet) and use the Count option. Best, Eric ... View more

Cut Fill is another approach to consider.  It's available with 3d or Spatial Analyst licensing. Best, Eric ... View more

I hadn't rebuilt the table before running zonal for that screenshot.  The numbers are definitely counts, not acreage or some other unit. Eric ... View more

You already touched on the answer.  See LAS to Multipoint.  I assume you will be building a Terrain from the data once it is in the geodatabase so be sure to output your multipoint feature class into a feature dataset.  Terrains must reside in a feature dataset and the source of the terrain must be in the same feature dataset.  It wouldn't hurt you to make a LAS Dataset directly from the .las files so you can QC it before loading into the geodatabase. Best, Eric ... View more

Dan, I think you should give 10.1 a try.  There are a few things that could speed it up for you.  Since it doesn't sound like you really want to keep the individual viewshed rasters permanently, but rather use each one to derive additional information, you can take advantage of the fact that in-memory workspaces support raster data in 10.1.  There is also true 64 bit background geoprocessing (added in SP1) to take advantage of any extra RAM you may have that wasn't being utilized in 32 bit space.  You have to install 10.1, then sp1, then the 64 bit background gp stuff.  You can get the setup here. http://support.esri.com/en/downloads/patches-servicepacks/view/productid/189/metaid/1913 Make sure you are deleting/cleaning up each in memory raster before going to the next loop. Best, Eric ... View more