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Hi all, Hoping someone can help with this problem. What I'm currently attempting to do is to create riparian buffer zones around different lengths of stream (so I can analyze how fire in the riparian area affects stream variables at different scales). I've already created 20-m riparian buffers that span the entire catchments of the streams I'm interested in and extracted the fire severity values for the buffer zones in those catchments (the colored rasters you see on some of the catchments). Now I aim to scale down to buffers at 0.5, 1, 1.5, 2, 2.5, 3, 3.5 and 4 km upstream of my study points. I want to do this because it's likely that conditions in the riparian zone only affect stream variables up to a certain distance away from the study site, but I'm not sure what the limit to upstream influence is. I already know how to create multi-ring buffers from a certain point, but those only use Euclidean distance from the survey site and don't take into account the curving of the stream. I want to measure the distance using the stream polyline itself. Here's what I've done so far: 1) I took the stream network polyline for my AOI (reach_lmfs) and dissolved all the reaches into one feature (so it wouldn't be composed of thousands and thousands of features, each its own line feature). 2) Using this new polyline (NetworkDissolve), I tried to use the Split Line at Points tool. The points I was attempting to split at were the study site points (sitePoints). My aim here was to get separate feature classes consisting of unbroken lines starting at the sitePoints and including everything upstream. 3) Oddly, the tool did not do this. Instead, it broke the NetworkDissolve layer back up into its original component reaches (I have no idea how!). This layer is called Take3Split. If the tool had worked, my next idea was to use the Split command on the Editor drop down menu to split at a certain distance upstream from the site points (measured directly on the stream lines) and using those split lines of the specified distances upstream from the points, create new points, measure what the diameter of the circular buffer should be, and then make the buffers using those distances. Any advice/ideas? Maybe I am going about this the wrong way and should be using linear referencing instead? Or network analysis? Neither of which I know anything about, of course. here's a link to a map package on Google Drive which has all my layers and necessary data so you can see what I'm talking about. https://drive.google.com/file/d/0BxKVn0O6wccZaEplWEFxcHE4blU/edit?usp=sharing Thanks! Emily
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07-14-2014
03:20 PM
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I'm trying to use the Zonal Statistics as Table tool (Spatial Analyst) to summarize the stats of a number of rasters within the feature 'zones' of watershed polygons. I keep getting this error: ERROR 010160: Unable to open raster t_t_t2\t_t_t2. Zonal statistics program failed I looked up the documentation on the error and here's what the Help has to say about it: "Description The grid could not be successfully accessed. This may be due to incorrectly specifying the paths or not having permission to access the data folders. If the path and permissions are okay, the next possible source of the problem may be the result of missing required component files in the grid's folder. A valid grid must have, at minimum,dblbnd.adf, hdr.adf, and sta.adf files, as well as at least one pair of files in the format w00n00n.adf and w00n00nx.adf (where n is typically 1 but can be more for multitiled grids). If any of these files is missing from the grid folder, the grid is considered invalid. Note that for integer grids, a vat.adf file is also usually present but not necessary. Consult the documentation for more information about the ESRI Grid format. If all the required components are present, it is also possible that the files that contain the binary raster data (the w00n and w00nx files) are internally corrupted. Solution Check that you have correctly identified the dataset and that you do have read permission. If this has been done and the problem continues, you should then determine whether the grid is a valid one. First try displaying it. If you cannot display it, check to see that all the required component files are present in the grid's folder. If there is no sta.adf file in the grid directory, try creating one with the Calculate Statistics tool. If its data files seem to have been corrupted, you may need to re-create the grid. Hopefully you have a backup copy that can be used or can run the process that created it again." The rasters that are supposedly not accessible are FGDBR, continuous type, 16 bit signed pixel. Working through the list of troubleshooting diagnostics, I eliminated the following: They all have attribute tables, and I exported them from the .gdb to check to see that they all have the required component files in the grid folders, which they do. They all have read permission and they all display fine. They all have .sta files. Arc Help's next helpful tip is that 'maybe they're corrupt.' But how do I tell if they're corrupt if all of the above attributes are working fine? One thing I thought of was this: They are all mosaics made from other rasters (note they are NOT mosaic datasets, I used the tool Mosaic to New Raster so they are all actual rasters as far as I know) and I am wondering if something went wrong in the mosaicking process and now they are buggy. I just need a diagnostic to figure out if the files are corrupt and why the Zonal Stats tool can't access them. One other weird thing is that two of the mosaicked raster files DID work OK with the Zonal Stats tool (while the other 16 didn't) for some totally unknown reason. I went through and systematically examined the properties of these two outlier files as compared with the ones that are misbehaving, and they all have the same properties so I'm not sure why Arc *can* access them while it *can't* access their brethren. Thanks. GIS Wizard-in-Training Emily
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04-29-2014
06:35 PM
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Beaver15 is a feature class. You are not selecting a feature by using it as the output extent. It may contain only one feature, but the feature class is not what you need to select to get the behavior you want. Make a layer of Beaver15 -> [Make Feature Layer (Data Management)] and then select a feature in Beaver15 -> [Select Layer By Attribute (Data Management)] and then pass that layer-with-a-selection to the clip tool as the in_template_dataset instead of the whole feature class.... Hi Mark, I followed your instructions to the letter, but am still having the same problematic results. Any other thoughts? Thanks, Emily
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04-17-2014
01:25 PM
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I notice that the help for this tool in both 9.3 and 10.1 says: When using ArcMap, you also have the ability to use the selected features as the clipping extent. But the 10.1 help goes on to say: If a feature within the feature class is selected and Selection Extent is checked (clipping_geometry is set to ClippingGeometry), then the output clips out the areas that are selected. If a feature within the feature class is selected but Selection Extent is not checked, then the output clips out the minimum bounding rectangle for that feature. I don't see in your model where the significant polygon is selected. It seems that even if there is only one polygon in the fc, you need to select it to get the behavior you want. Mark-- as a follow up, here is a screen shot of the parameters I set for the Clip tool. You can see that I selected the polygon Beaver15 as the output extent (the f.c. it is linked to in the model) as well as checking the Clipping Geometry box. What am I missing? [ATTACH=CONFIG]33150[/ATTACH]
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04-16-2014
12:41 PM
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Emily, did you try and use this tool instead of clip? Let me know if that worked. Tim Hi Tim, I played around with Extract by Mask before I started using Clip. It doesn't handle the rasters well if they're outside the polygon of interest (ie instead of just ignoring them, the tool crashes because it doesn't know what's going on). So I moved to Clip.
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04-16-2014
12:31 PM
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I notice that the help for this tool in both 9.3 and 10.1 says: When using ArcMap, you also have the ability to use the selected features as the clipping extent. But the 10.1 help goes on to say: If a feature within the feature class is selected and Selection Extent is checked (clipping_geometry is set to ClippingGeometry), then the output clips out the areas that are selected. If a feature within the feature class is selected but Selection Extent is not checked, then the output clips out the minimum bounding rectangle for that feature. I don't see in your model where the significant polygon is selected. It seems that even if there is only one polygon in the fc, you need to select it to get the behavior you want. Actually, I did check the Selection Extent in my model. You can't see it in the screenshot, because to check this box you have to double-click on the Clip tool in the model and set your parameters inside. That's part of my confusion. Why is this model not clipping out the rasters not within the polygons of interest, EVEN THOUGH I checked the Selection Extent box?
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04-16-2014
12:29 PM
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I'm using Clip (Data management) to clip a number of fire severity rasters to some watershed polygons. The aim is to get just the area of each fire within the relevant watershed polygon. I have this set up in Modelbuilder so I can automate it to some extent, just changing the Output Extent (watershed polygon feature class) with each model run. In Clip, I have specified "Use Input Features as Clipping Geometry." When I have used this model previously, I got my desired result of just getting the part of the raster than overlapped with each polygon; any fires that DIDN'T have any overlap with the polygon in question just showed up as EMPTY rasters (which was great, not a problem). Now when I try to use this model, I do get the fires that overlap, clipped using the polygon geometry, but fires way outside the polygon don't conveniently process as empty rasters like they did before: they show up in their entirety. I could go through and weed out all these non relevant fire rasters by hand, but I have 48 fires and 18 watersheds and a bunch of other geoprocessing operations I need to run on the clipped fires. Why is this happening even though I specified "Use Input Feature as Clipping Geometry" and even though it's never happened in previous uses of this model? Screenshot of model: [ATTACH=CONFIG]33133[/ATTACH]
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04-15-2014
04:37 PM
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