I tried r.surf.contour but using the vector contours converted to raster, it didn't work either. I'll try the actual lidar point and get back to you. Maybe the contours leave wide empty spaces (it is a pretty flat terrain) and it makes computation more difficult.<br>
<br>Thanks.<br><br><div class="gmail_quote">On Mon, Sep 20, 2010 at 11:19 AM, Markus Metz <span dir="ltr"><<a href="mailto:markus.metz.giswork@googlemail.com">markus.metz.giswork@googlemail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">kapo coulibaly wrote:<br>
> I tried v.surf.contour<br>
<br>
</div>Please try r.surf.contour<br>
<div class="im"><br>
> and after about 24 hrs of computation the progress<br>
> bar was still nowhere to be seen. I'll try to acquire the points from the<br>
> county. But i converted the contours to points and tried the whole series of<br>
> v.surf (rst, bspline, idw ...etc) with the same result as i stated<br>
> previously. But with 50 ft resolution I can complete the computation.<br>
> Here is the output for g.region to answer your question about nrows and<br>
> ncolumns<br>
><br>
</div>...<br>
<div class="im">> rows: 7246<br>
> cols: 8750<br>
> cells: 63402500<br>
><br>
</div>Weird, that's only 63 million cells, shouldn't cause memory troubles.<br>
With 8GB RAM, interpolations should be no problem (I tested with<br>
several 100 million cells), but depending on the settings, can take<br>
some time.<br>
<br>
Markus M<br>
<div><div></div><div class="h5"><br>
><br>
> Markus Metz wrote:<br>
>><br>
>> kapo coulibaly wrote:<br>
>> > I'm trying to interpolate a raster from a shapefile (points or<br>
>> > contours).<br>
>> > The shapefile is a 2ft contour lidar-derived elevation and I need a 10<br>
>> > ft<br>
>> > resolution DEM.<br>
>><br>
>> Extracting contours discards a lot of information, results are more<br>
>> detailed if a raster surface is interpolated straight from the LiDAR<br>
>> points. Try any of the v.surf.* modules with the LiDAR points, not the<br>
>> contours.<br>
>><br>
>> > Obviously even on a dual core dual processor 64 bit<br>
>> > workstation with 8 GB of ram I couldn't complete the computation.<br>
>><br>
>> How many cells (rows, columns) are in the current region? Did you use<br>
>> r.surf.contour? The -s flag might help to reduce memory requirements a<br>
>> bit for very large datasets.<br>
>><br>
>> Markus M<br>
>><br>
>> > Is there<br>
>> > an automated way to slice the domain in smaller pieces, carry out the<br>
>> > computation and piece them back together afterward? I'm thinking of<br>
>> > writing<br>
>> > a script but i was wondering if it has already been done.<br>
>> ><br>
>> > Thanks<br>
>> ><br>
>> > _______________________________________________<br>
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>> > <a href="mailto:grass-user@lists.osgeo.org">grass-user@lists.osgeo.org</a><br>
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>> ><br>
>> ><br>
><br>
><br>
</div></div></blockquote></div><br>