Latest Contributions by DavidMedeiros

I'm with the perceptive Mr. Quinn. You need to be very careful with .xls and .txt tables that they follows Microsoft Jet/.shp/.dbf file naming limitations: No tables or field names starting with a number, no spaces, no special characters (except "_"), short (10-chars). To avoid trouble, I try to follow these rules with all datasets. You can always be more creative with field aliases and layer names, but the datasets themselves should use "safe" names. If you do that, field names are also less likely to be garbled if the geoprocessing workflow goes through  .shp or .dbf formats. If you violate these rules, the tabular data may be read okay, but joins are not likely to work. As for the Copy Features tool, I believe it's a it's a much more useful method than data/export, since when you want to do it again (say after you change the underlying data), you don't need to go wandering through the interface, you can instead pull the Copy Features out of Geoprocessing results and re-run it. The Copy Features tool also is guaranteed to honor the specified environment settings for Current Workspace and Qualified Field Names. Just wanted to get back to this after having reviewed the input table. As far as I can see, no special characters, no numbers first, no spaces etc. I always follow the same rules but hadn't specifically checked this students table so wasn't sure. It may just be a bad table creation process leading to some underlying issue with the table itself. Although I can't see how it would successfully join to a layer but not export. As for exporting dynamic joins and selections, I typically use the data>export method because its right there on the layer. For the researches and academics I work with the contextual right click tools are often easier to find than toolbox tools and it fits their one-off work processes better I think. That said, the Copy Features tool obviously works better with iffy table joins so maybe I need to switch to that tool right away. ... View more

That is indeed the usual approach. I was simply offering another approach, since the first appeared to be giving mixed results. I appreciate the help, my exasperation wasn't pointed at you. I'm frustrated with the software! For a workaround using the copy features tool seemed to work ok and requires less manual work than the method above but its good to have multiple solutions. But I really need to understand the underlying issue and how to resolve it not just for this student but for future ones as well. I work with dozens of students a quarter here and rely heavily on this function to make permanent copies of their analysis results and table joins and I can't be resorting to workarounds for such a basic function all the time. ... View more

I'm assuming you are joining your xls layer to the points feature class (not the other way around). You could create dummy empty fields before the join (with same data types as the xls table fields) and then after the join, populate those fields based on the joined table fields. That way, the data will remain permanently in the points feature class, even after the join is removed. Joining table to points, then using Data>Export Data... to make a permanent copy of the points layer. I've done this hundreds of times and is basically the primary method for making a join permanent in ArcGIS. I've encountered the empty export issue a few times here and there but not the problem I described 2) above. Either way this is generally a straightforward function that we use all the time in Arc. It may be here data that's causing the problem, but I can't think of why. ... View more

A couple approaches come to mind:  the Near command, described here or perform a buffer around each earmark point and then geoprocess the buffers into/with the districts. I'm purposely leaving this a little vague as I'd like your student to figure out the specifics.... Thanks. We usually just help with general understanding of the software and science itself but with no actual GIS curriculum on campus we often have to delve into holding hands through analysis design as well. I'd considered buffers but there may be cases where a buffer would cross into nearby districts that don't actually belong to the city the earmark is in. Dialing in the exact right tolerance for a few thousand entrie3s across all 50 states would be difficult if not impossible. I may have come up with a solution though. I'm intersecting the ESRI placeply layer with the congressional districts to get a layer of polygons that contain both the district id and the city it falls into (or more specifically, pieces of the districts broken into their city portions). Table join the earmarks to the intersected layer by city/sate name then merge the output back into districts only on the district name. Still need to figure out the count and proportional sum issue but I think this moving in the right direction. Still looking for input though. ... View more

Strange.. I just tried to make the iterators connect to the ascii 3d tool, no problem, immediately connected as input. I don't know what would be wrong, have you updated to the latest SP? Interesting. What's the ASCII 3d tool? Is that the exact same tool as "ASCII to Raster"? I'll check our SP version when I'm in next (not until Tuesday). Thanks for checking. ... View more

What i see right away is the raster iterator. have you tried using the Iterate files instead? it reads files in a folder and can push that file to a tool, such as the ascii to raster tool Tried all of the iterators, none will link as an input. The "Iterate Files" specifically only has the option to set itself as the precondition to the ASCII tool. ... View more

I think Featue To Line tool (ArcInfo license) breaks lines where they intersect or share a segment. Each output line carries the FIDs of all the sharing lines, or -1 for no sharing line with an input fc. You would need to add a field to the result and calculate the count of FIDs that are not -1 by an expression. Again, thank you. That worked as well. I never look to these tools as geometry tools but should probably know more about them (meaning the "feature to..." tools). I did have to massage the table after words. There may be a more automated way of doing this but I simply used a series of selections and field calculations to change the values in each of my 6 FID fields to either a 1 or 0 then used the field calc to sum those into a new column. Now looking at how to create an accumulation of values for each segment based on its location in the river network and the values of all downstream segments. This is going to be a lot more involved and complex so I'll just post a new topic. ... View more

Thank you for letting me know. You are welcome. I am glad it worked for you.  🙂 I have a new similar question if you're interested? I have 6 line feature classes, each one is of a particular fish species distribution in the Oregon river system. Each feature class contains only the line features where that species is present, some lines overlap between the 6 layers, some don't. I want to output a new layer that is a collection of all the river segments from the 6 layers where each segment contains the count of the species in that segment and the unique species names. Union (Analysis) looks like it does what I want but this is a polygon only tool. I think I could do this thru a series of spatial joins to a master hydrology layer but a one time merging of the 6 line layers would work better. Any ideas how I could best tackle this analysis? ... View more

When you run Spatial Join, you can specify a Merge Rule - Count on a field. In your case, for each line you can get a count of matched dam features (FIDs). Sorry for the late reply, thank you Dan, yes this worked great. ... View more