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Hello again, We're in Connecticut, for those who may be wondering. Greg On Sat, Mar 29, 2014 at 11:41 AM, Gregory Andersen <[log in to unmask]>wrote: > Hello, listserv! > > I'm trying to do a stream network analysis, and I was hoping you fine > folks could give me some pointers. Here's the problem: > > We (myself and DEEP inland fisheries) are trying to quantify the effect of > stream culverts on fish travel. We have fish sample data, more for the > culverts, point shapefiles for each, and the high-res NHD stream > geodatabase (with geometric network). What we want to be able to do is > trace up the stream(s) a certain distance from the culvert, collect any > fish sample data, trace down the stream(s) the same distance and collect > the fish sample data, then get a table with the culvert data, fish sample > data, and the distance *with the upstream/downstream spatial > relationships. *This part is key. We also want the ability to stop the > trace at a culvert. > > I've attached a PDF with some figures to help show what I mean. The first > page shows the trace we're trying to do, and the second shows the result we > want. The third page shows a scenario where we want to stop the trace at a > culvert. The fourth shows a situation where we need to trace along multiple > streams. (For this one, not only would we want our table to show that the > samples are upstream, but also that they're on separate tributaries). The > fifth page shows why we don't want a simple distance analysis; it needs to > be along the streams. The sixth shows an example of being able to limit the > distance. > > The big thing is that this process needs to be automated. We have data > for a decent chunk of the state, and it won't be practical to manually go > through each culvert. The output needs to be something that can be dumped > into a statistics program with minimal data processing. > > I've attached copies of the culvert and fish sample point shapefiles. NHD > database can be found here [http://nhd.usgs.gov/data.html]. Any pointers > would be greatly appreciated! Please contact me for more info or anything > else. > > Greg > ------------------------------------------------------------------------- This list (CTGIS-L) is an unmoderated discussion list for all CT GIS Users. If you no longer wish to receive e-mail from this list, you can remove yourself by going to http://listserv.uconn.edu/ctgis-l.html