Hi John:<br><br>You can import the triangular mesh as a vector file by first importing the nodes with v.in.ascii and by creating a three column table (as you have three water elevation values) linked to the id number of each node. To create the triangular mesh run v.delaunay.<br><br>Jaime<br><br><b><i>John Overton <jd3@renci.org></i></b> escribió:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"> Hi,<br>I'm new to GIS topics, so please forgive if this is an obvious question.<br><br>I have some coastal data that is in the form of a triangle mesh where <br>the triangles are of different sizes. The triangles are subdivided the <br>closer they get to the coast. The smallest distance between two <br>vertices in the mesh is about 90ft(27m). Each vertex in the triangle <br>set holds the water height at that location. Each vertex also has a <br>lat/lon associated with it.<br><br>I want to get this data into a
GIS system like GRASS. I have not seen <br>features in any GIS system so far that allow an unstructed grid of data <br>like this to be easily read in. Please let me know if I am not correct <br>on this, because the ideal situation would be to enter the data as is. <br>However, if I am correct that I will have to transform the data, do any <br>of you have strong ideas about the way this should be done?<br>First, I thought about using shapefiles, because the data is in a <br>polygon format right now. Each triangle really has 3 different water <br>height values, though, so I thought shapefiles would not work since they <br>seem to describe a polygon that maps one value to the area it spans.<br>Next, I found the GEOtiff format. For this, I imagine I would have to <br>transform the triangle mesh into a raster format, and include a <br>projection. Right now there are lat/lons for each data point. Is there <br>any advice on how to accomplish this? One drawback that I see
to this <br>is the enormous amount of raster data I would need when the resolution <br>is 27m between data points where the water meets the coast. If I used <br>this approach, I thought I could create several different geotiff files <br>strategically placed to cover the NC coast. Is there a certain size, <br>that hits a sweet spot with GIS systems?<br><br>Please help!<br><br>Thanks,<br>John Overton<br>_______________________________________________<br>grass-user mailing list<br>grass-user@lists.osgeo.org<br>http://lists.osgeo.org/mailman/listinfo/grass-user<br></blockquote><br><p> 
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