<div dir="ltr">Moritz et al,<div><br></div><div>Thank you for the helpful suggestions. One of the problems I have is that about half of the points are in a tidal estuary where the elevations are all zero (sea level); so utilizing the elevations to sort will not work -- I have several thousand points I'm dealing with, which I obtained by doing a vect-->rast conversion and then got the points from the rast (I know this sounds screwy).</div>
<div><br></div><div>I have to explain what I'm doing. I want to use <span class="" style="color:rgba(0,0,0,0.498039);font-family:arial,sans-serif;line-height:18.200000762939453px"> </span><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px"><span style="font-weight:bold">r</span>.<span style="font-weight:bold">inund</span>.fluv to generate a flood inundation map. The problem stems from the fact that</span> I have a USACE HEC-RAS model implementation which was not georeferenced, from which I have modeled water surface elevations from a historic flood. From an ascii output file, I basically have the channel centerline locations (x,y) and water surface elevations and I have calculated the distance to the river mouth at each point. In GRASS I have independently, using a UTM map projection, the channel centerline as a vector. I have also identified the corresponding upstream and downstream end points, which identify the same locations -- so I plan I 'mapping' the HEC-RAS water-surface elevations (WSEL) at the un-georeferenced channel centerline locations based on scaling the entire river reach length between this data and what I have in GRASS. I can use the scaled distance from the river mouth to spatially interpolate locations where I know the WSEL.</div>
<div><br></div><div>The GRASS addon command <span class="" style="color:rgba(0,0,0,0.498039);font-family:arial,sans-serif;line-height:18.200000762939453px"> </span><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px"><span style="font-weight:bold">r</span>.<span style="font-weight:bold">inund</span>.fluv needs X, Y, WSEL as an ascii file.</span></div>
<div><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px"><br></span></div><div><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px">Now if I can go directly from the GRASS vector centerline and output verticies of that feature, so I have the x,y locations of the verticies my problem would be solved. I looked at v.distance and other modules but could not see how to generate the verticies and export them -- but, in the end, I need an ascii file of centerline point locations in upstream to downstream order. I have/am writing Perl scripts to manipulate the data. I was afraid the order would not be preserved by v.out.ascii, which was confirmed by my script that calculated the distances from the river mouth when I saw them starting to bounce around in odd ways as I looked at the calculated values when I looked at the downstream to upstream distances.</span></div>
<div><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px"><br></span></div><div><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px">Cheers!</span></div>
<div><span class="" style="color:rgb(84,84,84);font-family:arial,sans-serif;line-height:18.200000762939453px">Tom</span></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Apr 15, 2014 at 5:21 AM, Moritz Lennert <span dir="ltr"><<a href="mailto:mlennert@club.worldonline.be" target="_blank">mlennert@club.worldonline.be</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">On 15/04/14 08:13, jctorres wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello<br>
<br>
You can create a map of these points contining the elevation as<br>
attribute. Once you output this map you could sort points using the<br>
elevation values.<br>
<br>
you can do this for instance using v.to.rast to convert the points to<br>
raster, them combine this map with elevation using r.mapcalc (assigning<br>
elevation to the points), and them output the map using r.out.xyz.<br>
To sort the points you can use any sort program or a spreadsheet.<br>
</blockquote>
<br></div>
Maybe directly using v.what.rast might be easier...<br>
<br>
And, Thomas, have you checked the category values of the points ? If the points were created in stream order than the cat values should give the correct order.<span class="HOEnZb"><font color="#888888"><br>
<br>
Moritz</font></span><div class="HOEnZb"><div class="h5"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<br>
Best regards<br>
<br>
Juan Carlos Torres<br>
<br>
El 15/04/14 04:52, Thomas Adams escribió:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
All:<br>
<br>
I have a collection of points that represent the centerline of a<br>
river. I need to output them in upstream to downstream order (or the<br>
reverse). A simple v.out.ascii does not do this because of the channel<br>
meanders. It's critical to get the x,y locations of these points in<br>
the correct order.<br>
<br>
Any help is appreciated!<br>
<br>
Regards,<br>
Tom<br>
<br>
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