Latest Contributions by MarkBoucher

Convert the viewshed raster to a polygon and select by location (do points intersect polygon). ... View more

What you could do is process the data set with the added businesses. Then go into the existing data properties and change the source to be the new revised data set. If you name the datasets somehow to record the date, you have a backup from each change in data and at some time you could plot them to compare changes. This would save you from messing with the legend unless there was a record that required a new symbol. Also, once you have the symbology the way you like it, you can create a layer file. A layer file contains the symbology as well as the file bath to the data. After you add the revised data to the mxd, you can choose that layer file to symbolize the data you added using the import button on the symbology tab. Mark ... View more

I've not heard of ArcGIS being able to do this. You can add X and Y fields to the feature class table then export the table with the X and Y (but, you probably already know that or the raw input was coordinates and you wouldn't need to do that). After that, since the points seem to be lined up, you could do the math outside of ArcGIS assuming they are only changing in one direction. Via a Google search of "Predict a position" I found several sites that might provide insight or methods address the problem mathematically. For example: http://www.quora.com/How-can-one-predict-the-position-of-a-moving-object-given-its-previous-positions ... View more

When you created the stream raster, were the raster values Null outside the streams? Maybe when adding rasters, you get no results where the values are Null (I could be wrong about this and don't have time to test it). Use the raster calculator and an IsNull() test in the Con() function to change the null values to 0 (zero). It would be something like this if the stream raster is "breachlines": Con(IsNull("breachlines"),0,"breachlines") Then when you add the stream raster (with a negative number where the streams are), you will get a raster that has changed just where the stream raster values are. ... View more

You are performing the flow direction on the filled DEM, right? ... View more

Do you know if the ArcHydro tool provides some functions to approach a solution? (sub-dividing a watershed relating to slope?) I do not know if Arc Hydro can do that. It can automate the watershed subdivision based on an area, but I've not heard of it using choosing the watersheds using slope. ... View more

Arc Hydro does not do pipes. It works off flow direction determined by the DEM and has tools to let you modify the DEM to make it hydrologically correct.  You can use Arc Hydro in flat areas by using its tools to "burn" in the pipes like trenches and "building walls" to control the main drainage paths and watershed boundaries in the DEM so the flow direction is hydrologically correct. It does not calculate depth of flow for pipes or channels. There are tools to export the data from GIS to other modeling programs. HEC-GeoRAS and HEC-GeoHMS are two free programs developed by ESRI for the US Army Corps of Engineers to export data from GIS to open channel flow models and hydrology models respectively. Other software companies may have their own proprietary tools for doing the same for their models. ... View more

I search using "010024 : Error during conversion" and found: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00vq00000002010024.htm Based on that: Make sure your layers are in the correct coordinate systems. Make sure your processing extent covers your work area. Make sure the raster is floating point. Make sure you have permissions to read/write to the directories and files. ... View more

You could do it "the hard way". I commented on another thread where the user wanted to analyze the values around a grid cell. I found the "Shift" tool. http://forums.arcgis.com/threads/75804-surface-angle-in-each-cardinal-direction?p=265962&viewfull=1#post265962 Later I used this myself for all 8 directions to make temporary grids for each of the 8 directions. Each shift is to one of the eight directions. My grid dimension is 10, so I have (10,10) (10,0) (10,-10), (0,-10), (0,10) (-10,10) (-10,0) (-10,-10). Then I used different tools to get the results I wanted. You could do the same. If you use Cell Statistics tool with the choice of "Max" of the eight rasters, any place where the max is 0 and the original grid is 6 you should make the results 0.  Otherwise the value should be the same as the original. You can use the Con() function for making this decision. I did my work in model builder and below is an image of my modified model for your situation. [ATTACH=CONFIG]21989[/ATTACH] ... View more

I've never done this, but it could be that if you set the fill limit to really low the fill would be enough to let you get the stream definition and not fill the low areas as much. However, the streams would stop at embankments like the road creates. You could do a quasi Arc Hydro move like this: Create a polyline layer (call it breachlines) Draw breachlines polylines through embankments like the road. Create a field in the polyline layer for a floating point value. Put the number -1000 in the field for every feature in breachlines Convert breachlines to a raster using the floating point value. (call is dropdem). Add the DEM and the dropdem rasters. This will "burn trenches" into the DEM (call result burneddem). Perfom the fill tool on burneddem (call result filleddem) Perform raster math (DEM-filleddem) and check to see if there are locations that need breachlines. Repeat 2-9 until you are satisfied that you have breached enough "embankments" (this is a good time to use Model Builder!). You can also use breach lines to better define streams that the DEM can't "see" but you know are there based on other information. What's happening is that you are lowering the DEM (burning it) at the breach lines down 1000 feet or meters as "trenches" and the fill tool is filling the "trenches" back up to the elevation of the DEM at the lowest point next to the trench. When you perform the flow direction, etc. the streams should prove to be where you expect them to be. I believe this is exactly what Arc Hydro does except that you can control the width of the "trenches" and also you can create a transition zone (stream buffer) on the sides of the trenches so that any high points you trench misses will be smoothed out to make sure they drain to the stream. Hope this helps. ... View more

I suggest you use the raster calculator to compare the filled DEM with the raw DEM (filledDEM - rawdem). You will probably see that the fill sinks command filled in behind the road embankment explaining why you get the straight lines. On the raster calculator results you can use the raster symbology options to change the background value of the raster calculator results for color 0 ,0 ,0 to "Null" (or no color). I use the light blue color ramp. This makes it easy to see which grid cells have been changed and the color ramp provides some visual comparison of depths. The identify tools will give you the amount the cells were filled. ... View more

Look for solutions at this post: http://forums.arcgis.com/threads/48100-ArcHydro-Problem-Solvers ... View more

Ken, The error messages are usually not helpful to me. They seem to provide information only the ESRI developers can understand. After you get the error, try refreshing your ArcCatalog folder to see if it is created anyway. It could be there. If it is, you will likely need to set the Spatial Reference and it is likely useful. Are your project directories on a network or your local PC? I recently found that moving the project onto my local PC eliminated most of the crashes and errors. I make sure the under File>Map Document Properties I click the box for "Store relative pathnames..."  This lets me move the project back to the network server without disconnecting the layers. Mark ... View more

It just dawned on me that you are using the Spatial Analyst tools while I have been referring to Arc Hydro tools. Arc Hydro uses Spatial Analyst, but has more specific function and builds a network of the catchments, drainage lines and drainage points to allow more complex analysis. ... View more

It seems that maybe you are performing more analysis than needed to simply get to the point where you can delineate watersheds. You may want more details for your work, and if so, that's fine. When I process the DEM, I don't worry that much about the sinks. I perform the Terrain Processing using only the toolbar menu items highlighted in the image below. I follow arrow 1 and then arrow 2 and only use the highlighted tools. After I'm satisfied with catchment delineation  I will perform the items below arrow 2 since other watershed processing steps use the layers that result from them. [ATTACH=CONFIG]21840[/ATTACH] If you want to see which cells are lifted up (raised) in the fill sinks process, you can use the raster calculator to subtract the rawdem from the fil dem. The result is the amount each grid cell is filled. I use the symbology options to change the background value of 0 to the color "Null" or no color and I use the white to blue color ramp. This makes it easy to see which grid cells have been changed and the color ramp provides some visual comparison. The identify tools will give you the amount the cells were filled. Hope this helps. ... View more