Latest Contributions by curtvprice

Hi all - I'm having an issue with the Tabulate Area process in ArcGIS 10.1 (and 10.0).  I'm using NHDPlus catchments as the zone data and the NLCD land use raster for the classes to be summed.  I keep getting "ERROR 010010: Field not found. Invalid field index obtained." as an error.  Has anyone run into this?  I tried to run it on a small subset of catchments and it worked so I'm not sure if the size of the two datasets (quite large) has anything to do with it... Any help would be appreciated.  Thanks. When your raster datasets get large, the VAT COUNT field can sometimes break this tool - as it can only store 32-bit unsigned values (2.1 thousand million is the limit). You may have better luck if you can spatially tile your data. One thing to try is run this tool with the scratch workspace set to a file geodatabase instead of a folder -- the file geodatabase raster format is less susceptible to this problem. ... View more

  Is there a link to an updated tool that we could download? I've been posting updated versions here for review, please use at your own risk and send comments: ftp://ftpext.usgs.gov/pub/nonvisible/cr/nact ... View more

here is the code I used to get a large comment field to print over multiple lines. FYI - there's a really handy standard python module for wrapping text: textwrap. ... View more

Is there any way of creating a new raster by defining an extent without the raster resampling and changing the original cell values? Any assistance would be appreciated. The 10.0 help for Clip_management says that it will do raster snapping. I suppose setting the snap raster environment can't hurt though. If the clip extent specified is not aligned with the input raster dataset, the Clip tool makes sure that the proper alignment is used. This may cause the output to have a slightly different extent than specified in the tool. ... View more

it won't be related to any other databases. That's what they always say. :cool: ... View more

I've been tasked with creating unique IDs for a street light layer for a municipality, the client wants the unique IDs to be logical and sequential. "Smart" unique unique feature ids are generally frowned upon in a database design. They seem like a good idea at the time, but the more used a database is, the more pain they can create. Imagine you have the streetlight sequential going down the street and then a streetlight is added  in between 003 and 004 -- there you are, your nice setup is immediately broken. It's far better to have unique IDs and have other fields carry that kind of information like labels that sequence the lights going down the street. This is your client, though! There are many ways to approach this issue of sorting them going down the street. For example, you may be able to order ids along a set of streets going in the same direction by doing a NEAR to a point at one end and sorting by distance. You also may want to look into dynamic segmentation to address the points to locations along routes. ... View more

Thanks for the reply. However, the pre-7.0 coverages are not in *.e00 format, they are actually coverages. I suppose if I could convert them into *.e00, then use the tools as described it would work. Does anyone know how to package a pre-7.0 coverage to *.e00 file? These coverages should be readable - are you not able to view them? If you can view the coverages, as Richard said, you can copy the feature classes to a geodatabase workspace. If they are missing coordinate system information, and you know what it is, you can define the coordinate system after copying them using the Define Projection tool. You could do this in a model by using an iterator with the Copy Features tool. ps The only way to create an .e00 file is to have a copy of ArcInfo Workstation. pss in Arc 10, the e00 importer has been exposed as the Import From E00 tool. ... View more

Hi, I am a early user of ArcGIS. I am using version 9.3. I have a digital elevation model. I would like to sample the elevation values along some randomly selected transects. The transect does not have physical entity. From the map, I can see and select the length and direction of transects. In doing so, what I can do. How I can extract the elevation values along those transects ( of course, first I have to select the transect, how?)? Thank you very much for your help. I have spatial analyst toolbox. Do you have access to a 3D Analyst license? The 3D Analyst toolbar has functionality to do this. ArcGIS 9.3 Help: Creating profile graphs ... View more

Two helpful links Arc 10 help: Setting paths to data in Python os.path is very useful for manipulating path strings ... View more

One of the most effective approaches I have found to avoid problems with paths is to be very careful to pass only raster and feature layers to tools in Python scripting. This has sometimes (but not always) avoided problems for me, as this makes sure that the tool interfaces then don't need to parse paths -- you are passing the tool an object with an intact, parsed pathname associated with it, ready for ArcObjects to use behind the scenes. A special issue that comes into play is passing multivalues with GetParameterAsText. These come across as ";" delimited. This causes major problems when the inputs (layer names for example) contain semicolons! The only workaround is to use GetParameter() and pull out the pieces using a value table; however, this is so much trouble that I think a better approach is to just have better error trapping and inform your users to not do that! IMHO, users that use semicolons in their layer names and file names are just asking for it! ... View more

I have some property points for a city. In the data I have a field with either a 0 or 1 dependent on the type of property each point is. I would like to be able to map the percentage of properties which are type 1 across the whole city so we can find hotspots of the specific property type. We are particularly interested in being able to look at different percentages so that we can locate areas where, for example, the percentage of properties that are type 1 is above 20% and below 80%. It would be perfect if we could visualise the percentages as a surface (so maybe we could symbolise by percent band i.e. 0-20%, 20-50%, 50-80%, 80-100%). Given decision makers will be implementing decisions by political area (ward, precinct, etc) you may want to do this with feature data, ie do an Identity (or join by location) of the your property centroid points with political unit polygons and then summarize numbers of "type 1" and "other" points in each polygon. (A nice trick to this is to assign them scores of 0 and 100 and calculate a mean - this computes to percent.) This approach may also avoid problems with your spatial distribution of points skewing your results. I realize this isn't a Spatial Analyst solution to your problem but it may be a better place to start. You can get fancier with hot spot analysis once you know the basic patterns. ... View more

With help from the forum, I thought I figured out how to write a cursor to work in 9.3 and 10 but users report not. Here's how I do it. This should run at 9.x and 10.x. Note the use of a logical expression to check for None (definitely works in this context) and, a try/finally block to make sure the cursor objects get deleted. import arcgisscripting gp = arcgisscripting.create(9.3) try:     rows = gp.SearchCursor(crosswalk,whereclause)     row = rows.next()     if not row:          gp.AddError("check the Two630FC_IDPKxwalk.dbf table for Two6FCs -->" +two6FC)          raise     while row:         # do row stuff...         row = rows.next() except:     raise finally:     del row, rows The 10.0 arcpy syntax is easier, as search cursors return an iterable: rows = arcpy.SearchCursor(crosswalk,whereclause) for row in rows:     # do row stuff ... View more

Matt, thanks for the update. Before the edit window closes, could you enclose your python code in [thread=48475]code tags[/thread] to make it more useful for others? Just a note, I like to store datetime in GIS datasets and database tables as standard-format strings "yyyy-mm-dd hh:mm:ss" and calculate date values when needed in an analysis or selection, because it seems every operating system and file format seems to have its own scheme or limitations! Not an issue if all your data is in one database, but if you need to move the table from one place another, it seems data stored in date format can be more trouble than it is worth! ... View more