Latest Contributions by EricRice

Nola, The LAS specification requires that spatial reference information always  be included in the header information of all LAS files.  ArcGIS will  read and use the spatial reference information if one exists in the LAS files.  We know that not every producer of LAS follows the specification so there are tools to fix the header.  The link Tarun  provided is useful, but I think you are looking for the LAS to LAS tools which allow you to add or fix the projection information stamped into the LAS header. Best Regards, Eric ... View more

One more thing since you're on an old release.  The name of your raster indicates it was the result of a clip operation.  I believe in your version, the table is not automatically updated and even records that were clipped off are still in your table with counts set to 0.  For example, in the data you sent, the raster has Barley with a significant number of pixels in the count column, but when I do zonal on it I get 0 for every county.  You should probably run the Build Raster Attribute Table tool to get an up to date raster attribute table before running Zonal Histogram.  It will make your output table look cleaner and won't be filled with 0's like in my last screenshot.  Back up/ copy your raster before rebuilding the table. Best, Eric ... View more

Hi Rob, Thanks for the data. I did a quick test using the workflow I described earlier and got exactly what I said we'd get.  What sp are you using with v10.0?  I am using 10.1 sp1 (the latest release). -Eric ... View more

Hi Qassim, These two links should get you going.  There are multiple ways to manage lidar data in ArcGIS. Using lidar in ArcGIS Common lidar data configurations You may also want to review, LAS dataset considerations, should you take the LAS Dataset route. Best, Eric ... View more

Darlene, Just to clarify what happened a bit for anyone else who visits this thread.  You made use of the Snap Pour Point tool.  The raster that is derived from this tool will have the extent of the input points if you leave the extent settings default when you run the tool.  Usually the point layer's extent is smaller than the DEM extent.  When you move forward in the hydro workflow (watershed tool) and you use the smaller extent raster as input, the tool's default behavior is to use the smallest extent of any of the inputs.  In other words, just the area of overlap between the inputs.  You can avoid this by setting the extent to the DEM when you run the Snap Pour Point tool, or like Curtis suggested, when you run Watershed. If you create an envelope of the points using the Minimum Bounding Geometry tool and overlay it with your original watershed result it should be quite clear why your catchments got 'cut' off. Best, Eric ... View more

Mike, The Spatial Analyst team recently published a blog post introducing the "Spatial Analyst Supplemental tools".  One of the supplemental tools is a Filled Contours tool. You can download the tools here: http://www.arcgis.com/home/item.html?id=3528bd72847c439f88190a137a1d0e67 Requirements: ArcGIS 10.1 Service Pack 1 and Spatial Analyst Extension The Filled Contours tool requires ArcGIS for Desktop Advanced or ArcGIS for Server Advanced and Spatial Analyst Extension. Best, Eric ... View more

Michael, You can't publish a mosaic dataset in a map service without the Image Server Extension. 😉 Shaun, As for the black/white checkerboard, this indicates the imagery could not be found by the server.  Since it happens when you zoom in, it sounds like the server has access to only the overviews, but not the source imagery.  Do you have the source directory registered with the server's data store and did it validate?  While we're at it, since you do have the extension, what happens if you publish the mosaic dataset as an image service rather than a map service?  Do you still see the issue with image service? Best, Eric ... View more

Robert, We will get this sorted out together... Originally, I assumed you were symbolizing the landuse raster using Unique Value rendering and thus the zonal histogram table's label field would have the unique values for the raster in that column and require joining the zonal output table back to the input value raster table where Label = Value to establish/retain the landuse descriptions.  I found that if you symbolize by Unique Values, but use the description field for the value field (on symbology tab) rather than the Value field, when you run Zonal Histogram the label field will automatically contain the descriptions your looking for so no further join is required.  Please see screenshot-1 of result I obtained with this method. Based on the table you sent and lack of label field, I do not believe you are using the Unique Value renderer.  My example case is simple with only 7 landuse categories so ArcMap automatically uses Unique Value, but if your data has more than 26 unique values (and it does) then ArcMap will display it with a stretched renderer.  If you leave it as stretched, AND your inputting a raster layer (rather than a raster dataset) then the layer's symbology defines the number of classes.  When it's stretched you get 256 classes so most of your landuse will be zero's for each county.  Hopefully this second screenshot helps clarify what is happening.  The table on the left is Zonal Histogram with the Unique Value renderer and the table on the right is with Stretched.  What you see is that the value 7 was stretched to 256 - county 1 still has 447 pixels of wetlands and county 2 has zero, but clearly using stretched is not the way to run this tool since the values for each landuse are stretched to the full 8 bit range and aren't really meaningful in terms of properly being able to join it back to get descriptions.  This is how you got cotton growing in Ohio! The stretched value was joined, not the real value.  😄 To summarize: 1. Use the Unique Value renderer on the landuse raster. 2. On the symbology tab, set the value field to the landuse description field like in screenshot-3. My description field just happens to be called Landuse. 3. Run Zonal Histogram. This should produce what you're looking for without further joins. Best, Eric ... View more

Right click on the toolbox that contains the model(s) and go to Save As > 10.0 toolbox. Best, Eric ... View more

Hi Robert, I personally dislike the formatting of the output table, but it's not hard to get the landuse descriptions back.  All you would have to do is join the output table back to the raster attribute table.  The output table has a field called LABEL which you can use to join back to the VALUE field in the raster. Once this join is in place you'll have landuse descriptions back.  Since each zone becomes a field, you can't really expect to join this back to the original polygon zones.  I have an alternative workflow where you convert the landuse raster to polygons and run the Tabulate Intersection tool (new at 10.1) then I usually follow that up with the Pivot Table tool before joining the table back to my polygons. Best, Eric ... View more

Hi Robert, You should check out the Zonal Histogram tool.  Your zones are the counties and the value raster would be your landuse raster.  This tool will give you the breakdown of each landuse within each zone. Best, Eric ... View more

What format is your input value raster?  The one named, 158-76.  It appears to be an Esri GRID, but you can't name our format like that and expect things to work.  In fact the only way to violate the rule for GRID naming is to rename it outside of ArcGIS.  Our system won't let you name an Esri GRID with a number in the first position. See about Esri GRID Format, specifically the section called Storage Limitations.  I believe you also have spaces in the path to the data, which has caused issues in the past... "C:\Documents and Settings\eiyoung\Desktop\Madagascar Research\Forest Disturbance Scenes\All GRIDS\158-76" " Best, Eric ... View more

Emma, Your model is not yet finished.  Remember that the Zonal Histogram tool outputs a table...so for each iteration you are going to get a table, but in the end you want these associated with the original buffers/points so you must merge each table created into a final output table so that you can join it back to the features using the Zone ID field.  You are in 'advanced' territory here.  You don't want merge to execute for each iteration either, which means you need to nest the iterative model inside another model that only contains Merge/Append.  You must also make use of inline variables.  I would also recommend taking advantage of the in memory workspace within Zonal Histogram for the output table.  You can use Collect Values to collect the individual tables (from the in memory workspace) prior to putting them into Merge.  Don't forget that you can extend the model a bit more to include the 'join' process back to the original features, and don't forget about looking into the Pivot Table tool. Let me know if you have any questions. 😄 Best, Eric ... View more

Emma, You must use an iterator for it to be correct.  When features are input, they are converted to rasters behind the scenes.  Because you have two features overlapping, the underlying pixel must choose which feature to represent. Each pixel can only be one value.  In the case of just two overlapping polygons, one would be correct and one would be smaller than it should be because the software has to choose only 1 of them during the conversion.  This is discussed in at least 50 other threads if you feel inclined to read up, and is discussed in the documentation.  See the 9th bullet point under Usage for Zonal Histogram.  If you want to visually see what I mean, you can convert your buffers into a raster to see that you don't get two values for each pixel where the overlap occurred.  It will pick one for you and you have no control over which one it picks.  These tools originally only allowed raster inputs, but because feature input was requested we allow it and do the conversion for you, but the underlying process to compute the output is ALL raster based analysis. Best, Eric ... View more

Hi Emma, Have a look at the Zonal Histogram tool instead.  Zonal Statistics doesn't give you the breakdown of each value within the zone and their counts.  I typically run the Pivot Table tool after Zonal Histogram to turn rows into columns. Your buffers overlap each other, so you need to iterate through each record (buffer feature) for the results to be correct.  See Iterate Feature Selection. Best, Eric ... View more