Latest Contributions by DavidMedeiros

I need to process a spatial join based on an attribute. I have a point layer with hydro power stations and a point layer with local fish species present in nearby streams. The problem is the species point layer has multiple points for a given segment of river, all with different species. I can't do a simple spatial join from hydro to species points becasue I don't want the first matching record, I want the closest matching record. I've given the hydro features the river ID of the nearest stream which in turn relates to the river ID of the species points. I've created a model that iterates over the river ID field and uses that in an attribute selection before running a spatial join between the hydro stations and the species points. So for each hydro station I am only doing a spatial join against those species points that match that station river ID. The model appears to work, except that it applies the selected spatial join to all of the output fields, rather then just the record currently selected and over writes each successive join. See screen shot below. Any idea how to get this to only write the spatial join info per selected record without overwriting the hole table each time? OR, any alternate methods to solve this issue? ... View more

Given a set of points along a complex river network, and a set of municipal district polygons covering the points and rivers... how would you determine for each point if it was 'upstream' or 'downstream' of the closest municipality along the same river the point is situated on? See the attached image for a simplified version of what I'm trying to help someone do. Basically we have mines (A B & C), situated along a river network. And we have municipalities (1 2 3 4 & 5). I don't care about the municipality the mine is in, but I ant to know if each mine is upstream or downstream on the next closest municipality on the same river. This seems like a simple question, but the problem is in how to connect the mines to the municipalities on their network when there is no common identifier for the river segments they are on. So for mine B, how do I get the upstream/downstream value for municipality 4 rather than 5? One solution would be to simply get an elevation value at the mine and at the intersection of the river the mine is on at the municipal boundary, but I have no way to associate them. In the real data the boundary between each municipality is crossed by dozes of streams each. Still working this out but would love some suggestions. Dave ... View more

I'm helping a student run a simple OD Cost Matrix looking at the distances between homes in a village and all of the wells in the village along paths and roads. The student has digitized the "road" network. It's very simple and has been checked for geometry errors (none found). Following the help for Network Datasets on the resource center we created the ND, set a single attribute for length, set the evaluators values to our length attribute... created the ND and started the OD cost matrix tool. http://resources.arcgis.com/en/help/main/10.2/index.html#/Exercise_1_Creating_a_network_dataset/00470000005t000000/ But running the OD cost matrix tool has returned two different erroneous results. 1st, initially we used default settings and got back an error box saying that none of our origins found destinations. After changing the OD analysis settings for attribute parameters (to include all end points, vertices, and mid line junctions), we got back results but the link table showed that not all locations were being connected (each home shoudl have 35 wells linked) and the distances appear to be straight line, nit along the network (the actual distances not the links they draw). I've successfully run OD cost matrix in the past but using a regular street network built for ND analysis. I'm assuming there is something about our network that is the issue but I can't figure it out. I'm attaching a map pack with the files for investigation if any one would like to give it a try and let me know what we are doing wrong. There are two road layers in here, the major or original data, and the "minor" with extra paths that link the homes directly to the network. David ... View more

I have a set of geotiffs created in ArcGIS 10.1. The new images are saved by Arc as 16 bit 3 band tiffs, but show up in Photoshop as an all black, 16 bit grayscale image. I need to upload these images as 4 band tiffs, where the 4th band is an alpha or transparency channel. Aside form the fact that PS can't properly read the image, it also strips the geo ref headers when saving as a new type. Is ArcMap capable of exporting a 4 band tiff? Anybody know how to work with these files outside of Arc so they keep their header info? For reference, what I need to set as transparent are the black collars that geo referencing an image can create in Arc. Thanks, David ... View more

Is Esri ever going to implement admin control over credit usage by organization members? I've been hearing about this for a while now, I thought it was rumored to be a new function in ArcGIS Online as of this Fall but I believe as of now admins still can't directly control how many credits each organization member can have, or see detailed information on their credit usage, product by product, or action by action. From my perspective, helping administer ArcGIS Online in a University setting, the admin controls for ArcGIS Online are one of its weakest features and need some attention. I'd love to hear to what Esri's plans are for upgrading Admin control. Thanks, David ... View more