<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">A problem with which I am currently working relates to the r.walk feature, for calculating anisotropic movement cost between two points, and v.distance, for calculating the shortest distance between my archaeological sites (areas) and river drainages (represented as lines). I could convert everything to raster data, if that improves the ability to calculate what I am interested in, but that's a different story, and not worth noting right now...what I need to do has not been described by any of the available examples and questions, or maybe I am still not comprehending how to do it properly, but here is the issue:<DIV><BR class="khtml-block-placeholder"></DIV><DIV>I want to find the shortest distance between an archaeological site and a drainage. I do NOT want to specify to which drainage one should look from each site, because I want it to be the least cost to get to a source of water. I suppose that technically I would not NEED anisotropic modeling, because the trips would be round trip, but I still would prefer to do this with anisotropic distances because down the road I may want distances calculated from one site, to a drainage, to a different site, and back to the original site (for example, total shortest distance from a pueblo to a river to a grid garden back to the pueblo). </DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Therefore, the requirement of r.walk and r.cost to specify start/stop points is not good for me. </DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Obviously, first I need a cost surface. For ease of argument, I'm going to stick with slope and only slope right now. So, I have these data:</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>All_sites - vector, polygons of sites (I also have a point version of this map, where the centroids of the areas were converted to a point topology)</DIV><DIV>Drainages - vector, lines of drainages</DIV><DIV>DEM_16 - elevation at 16 foot resolution</DIV><DIV>Slope_16 - slope at 16 foot resolution (calculated from DEM)</DIV><DIV>Aspect_16 - aspect at 16 foot resolution (also calc. from DEM)</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Once I have identified the closest drainage based on least-cost-distance, I want to upload two columns to the All_sites db, one for the distance, one for the drainage identified as closest - just like v.distance allows.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>r.drain does some of what I want, but not completely. I have been staring at the manual pages and searching the archives for a while now, and it really seems that everyone has specified start/stop points in mind (all of the talk about Tobler's hiking function a few months back, for example).</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Chances are that I am making this more complicated than necessary, but I hoped there could be some sort of solution. If specifying a destination is really the way I have to go, I can convert my drainage lines into points, and just find the shortest distance to one of those points via a cost surface. But again, I still don't know how to let GRASS decide which of 2 lines, points, etc. are closer (via a cost surface) and then have it give me that least-cost distance.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Any ideas?</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Thanks much in advance,</DIV><DIV>Brandon </DIV><DIV><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">_______________________</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Brandon M. Gabler</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Doctoral Candidate</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Department of Anthropology</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">University of Arizona</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Tucson, AZ 85721</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Phone: (520) 621-8455</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">Fax: (520) 621-2088</SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;"><A href="mailto:bgabler@email.arizona.edu">bgabler@email.arizona.edu</A></SPAN></FONT></DIV><DIV style="; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;"><BR class="khtml-block-placeholder"></SPAN></FONT></DIV><DIV style="; font-size: 12px; "><SPAN class="Apple-style-span"><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">"Who? When? Whither? are the questions with which the archaeologist challenges the refuse heaps, scattered potsherds, and broken shafts, to tell of the builders who came and lived and went their way into the templed past." -- Edgar Lee Hewett, in</SPAN></FONT><SPAN class="Apple-converted-space"><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;"> </SPAN></FONT></SPAN><I style="font-style: italic; ; font-size: 12px; "><SPAN class="Apple-style-span" style="font-style: italic; ; font-size: 12px; "><SPAN class="Apple-style-span" style="font-style: italic; ; font-size: 12px; "><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;; font-style: italic; "><SPAN class="Apple-style-span" style="font-style: italic; ">Pajarito Plateau and its Ancient People</SPAN></SPAN></FONT></SPAN></SPAN></I><FONT class="Apple-style-span" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;">, 1938</SPAN></FONT></SPAN></DIV><FONT class="Apple-style-span" size="2"><SPAN class="Apple-style-span" style="font-size: 10px;"><BR class="Apple-interchange-newline"></SPAN></FONT></SPAN></SPAN></SPAN></SPAN></SPAN> </DIV><BR></DIV></BODY></HTML>