Latest Contributions by MarkBoucher

You have to process the dem. There are tools in Arc Hydro that do this. The tools let you "burn" a stream through the road embankment so the area behind the embankment is not filled during the fill sinks process. I've posted several Arc Hydro helps in the link below my signature. ... View more

Budi, I downloaded and processed your data. I think you shouldn't modify the str or strlnk raster. By modifying either of these layer you are making them inconsistent with the fdr layer. I don't think that is a good thing. You should modify the um_mainflow_u50n (stream) layer. This layer dictated where the streams go (the fdr layer). Modify the stream layer and reprocess from your step 1. Things to make the process less painful: If you are working on a network, move the data to your local PC. It will process much faster. Build a model in Model Builder. There is a pre-made model in the ArcHydro tool box. You can copy that to a toolbox in your project directory and run it. It will modify the model automatically to make the layers and rasters be saved to the right folders and geodatabases. If you modify the stream layer, you can run the model again instead of having to use the menus. Hope this helps. ... View more

If your project is on a network server, try putting it on your local drive. I will speed up the process. The Longest Flow Path process is the one that takes the longest. ... View more

When I start a project, I open a new mxd, load in a base layer with the coordinate system I want and save it. Then I load the dem and agreestream layers as well as inner and outer wall layers I will use. At this point, when I perform the Arc Hydro tasks, the target locations are automatically set. If I move the mxd and layers to another folder then I need to reset the target locations. (I now do my work on my C: drive, off the network, because I don't get as many errors.) The dem, agree streams and wall layers are the basis of the Arc Hydro work. (There could be others that I don't typically use like lakes/water bodies.) If these are the same, the results should be the same. So there have been a few times where I've had problems with the target locations and simply started a new mxd added these basic layers and let Arc Hydro set the new target locations. I found an old thread where the solution included renaming the normal.mxd and letting Arc Map create a new normal.mxd. http://forums.arcgis.com/threads/16059-Setting-Target-Locations-ArcCatalog. I just posted some guidlines on target locations to see if others agree on my understanding. You can find there at this link. http://forums.arcgis.com/threads/84833-Setting-Target-Locations ... View more

Topology tools are what I use for this type of thing. For this, the data needs to be in a geodatabase. Then you create the topology in that geodatabase and then create rules like "must not overlap" and "must not have gaps". Then there is a topology tool bar that makes these fixes easier. There is another process that may do what you want. I've heard of it only recently, but have not had to use it. ... View more

Try putting the layer on your local drive and not on the network drive. I've solved memory and other error issues this way. ... View more

Under ApUtilities>Addtional Utilities there is a Reset Target Locations function. Try that. Also, see the link below my signature. These are tips I have collected motivated by my own trials and errors. ... View more

Another approach. Treat your polygon like a watershed. Create a raster using your polygon. It needs to have a z component. Make "centerlines" (see pdf). I recently ran across a forum post about creating centerlines from bounding lines. (here�??s' one, I think there is a more recent one also: http://forums.arcgis.com/threads/76532-Creating-Automatic-polyline?highlight=centerlines) Make "cross sections" in the same polyline layer. There should be an automated way to do this. Use the new polylines as the agreestream layer for hydrology analysis in Arc Hydro. Clip the agreestream with your polygon. You may need to make a smaller polygon (use offset or buffer) to clip the agree streams layer so the lines don't cross the polygon boundary. Add one or more polylines that cross your original polygon boundary at the "outlet(s)" From here apply the Arc Hydro work flow (you need Spatial Analyst (SA) and could use SA tools instead): Recondition the dem using the agreestream layers to burn them into the raster. Build walls using your original polygon as the outer wall. Use the agreestream layer to breach the wall. Fill the sinks. Not sure if you need to do this since the raster is "flat". Run the flow direction tool. Run flow accumulation tool. You will now have a flow direction grid that you can use the hydrology functions in to delineate watersheds. The flow accumulation layer can be looked at to identify locations where the accumulation is a multiple of 1000 km2. Maybe then you can delineate the raster at these locations. You will have rough edges on the raster, but if the raster is fine enough these should be minimal. I would use model builder as you iterate to refine the steps of this process. Hope this gets you closer to your goal and good luck! ... View more

I believe this would only work if I had a smoother polygon. Can you simplify your polygon so there are not so many irregularities and then work with a template? ... View more

I want to create multiple polygons of equal area (1000 km2). Hannah, I would ask the person who wants this (even if it that is you), "Is there something special about the 1000 km2?  Can the areas be approximately 1000 km2?" Seriously, for you to accomplish this task with the spaghetti of a polygon you sent would seem to be impossible or at least expensive (time and money) to do it manually. Determine if there can be some leeway in this target of 1000 km2. ... View more

Unless there are special tools I don't know about, you don't "edit" the raster. You use tools on the raster to create other rasters. For example, if you use the hydrology tools in SA to "fill sinks" you end up with another raster with the sinks filled. To create the contours, you use the SA coutour function to make a polylline feature class of the contours. ... View more

My understanding is the GeoHMS does not create reservoirs. In the work I've done, I create an agreestream feature that goes through the reservoir embankment. This keeps the reservoir depression from filling during the fill sinks process. Then I put a batch point at the intersection of the agreestream and the embankment so that when I deliniate the watersheds I have a watershed and drainage point assocated with the reservoir. After I've create the HMS model, then I add in the reservoir. If when you say "created reservoirs" you mean "created stage-storage curves" I've not used GeoHMS for that purpose and I suspect you can't use it for that. There could be other tools for that. ... View more

I can't see the pour points in your image. My suspician is they are not "snapped" to your stream grid. Find a way to get the pour points right on the stream grid and deliniate again. ... View more