[GRASS-user] Bathymetric data

2012-08-23 Thread Lyle E. Browning
Hello, I'm searching for bathymetric data that can be uploaded of the bottom of the Atlantic Ocean that will include the seamounts. Basically at the same resolution that one sees with Google woud work for what I need. What I then want to do is "drain the bathtub" to see whether seamounts might

Re: [GRASS-user] Importing ASCII file

2012-08-23 Thread sotototo
Hi, Im new to Grass GIS and I have the same problem. I have an ascii Lidar data set with XYZ values in the following format. ncols 1999 nrows 1998 xllcorner 459000.27618609 yllcorner 298999.76202791 cellsize 0.5 NODATA_value - - - - - - -999

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Glynn Clements
Markus Metz wrote: > > So if I understand you correctly: 1.0e-15 is the smallest number for > > values in attribute columns although the values in a DCELL raster > > can be smaller? A bottleneck is v.what.rast which converts > > the queried raster values into text with 15 decimal points? > > So

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Glynn Clements
Markus Metz wrote: > > I have a GRASS raster map which contains small values (e.g 2.5e-15) among > > others. > > This is (dangerously) close to the IEEE limit of double precision > floating point values. If GRASS tests for fp precision, it regards > (absolute) values smaller than 1.0e-15 (GRASS_

Re: [GRASS-user] After Qgis installation - GRASS6.4 doesn't start anymore

2012-08-23 Thread Markus Neteler
On Thu, Aug 23, 2012 at 1:16 PM, Johannes Radinger wrote: > Hi, > > I successfully compiled and installed GRASS6.4 with "make -j2 && sudo > checkinstall && sudo ldconfig" > which is usually working perfectly. > > But after installing QGIS I can't start GRASS6.4 itself anymore. > I try to launch it

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Markus Metz
Another idea, maybe it helps in your case: You can use raster values as z values in vector points (r.to.vect -z) which would be in case of a DCELL raster the same like the raster values because both are double precision floating point. Markus M On Thu, Aug 23, 2012 at 4:10 PM, Johannes Radinger

Re: [GRASS-user] Coordinate systems?

2012-08-23 Thread Micha Silver
You can certainly transform vector and raster data from one Coordinate Reference System to another. As you have probably already realized GRASS is more insistant than some other GIS software regarding CRS. When you first startup a GRASS session you must choose you

[GRASS-user] Coordinate systems?

2012-08-23 Thread Charles E. Deaton
I've been looking at GRASS for a few months now and for the most can't determine if I can transform coordinate systems of vector data or not. I'm stuck. All of the data I use (shapefiles) have been in the same reference system (I think it's the reference system I'm talking about). I've been trying

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Johannes Radinger
On Thu, Aug 23, 2012 at 3:23 PM, Markus Metz wrote: > On Thu, Aug 23, 2012 at 2:40 PM, Johannes Radinger > wrote: I have a GRASS raster map which contains small values (e.g 2.5e-15) among others. >>> >>> This is (dangerously) close to the IEEE limit of double precision >>> floating poin

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Markus Neteler
On Thu, Aug 23, 2012 at 3:23 PM, Markus Metz wrote: > On Thu, Aug 23, 2012 at 2:40 PM, Johannes Radinger ... >> So if I understand you correctly: 1.0e-15 is the smallest number for >> values in attribute columns although the values in a DCELL raster >> can be smaller? Just for the record from so

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Markus Metz
On Thu, Aug 23, 2012 at 2:40 PM, Johannes Radinger wrote: >>> I have a GRASS raster map which contains small values (e.g 2.5e-15) among >>> others. >> >> This is (dangerously) close to the IEEE limit of double precision >> floating point values. If GRASS tests for fp precision, it regards >> (abso

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Johannes Radinger
>> I have a GRASS raster map which contains small values (e.g 2.5e-15) among >> others. > > This is (dangerously) close to the IEEE limit of double precision > floating point values. If GRASS tests for fp precision, it regards > (absolute) values smaller than 1.0e-15 (GRASS_EPSILON) as zero. > > v.

Re: [GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Markus Metz
On Thu, Aug 23, 2012 at 10:35 AM, Johannes Radinger wrote: > Hi, > > I have a GRASS raster map which contains small values (e.g 2.5e-15) among > others. This is (dangerously) close to the IEEE limit of double precision floating point values. If GRASS tests for fp precision, it regards (absolute)

[GRASS-user] After Qgis installation - GRASS6.4 doesn't start anymore

2012-08-23 Thread Johannes Radinger
Hi, I successfully compiled and installed GRASS6.4 with "make -j2 && sudo checkinstall && sudo ldconfig" which is usually working perfectly. But after installing QGIS I can't start GRASS6.4 itself anymore. I try to launch it from the Terminal like: x@y:~$ grass64 Cleaning up temporary files ...

[GRASS-user] Precision of raster/vector float values

2012-08-23 Thread Johannes Radinger
Hi, I have a GRASS raster map which contains small values (e.g 2.5e-15) among others. When I try to update a attribute column (Type = Float) of a corresponding point vector (using v.what.rast), all small values turn in "0". Thus I am curious about the precision of the float values of a vector fil

Re: [GRASS-user] creating two new maps from one existing raster

2012-08-23 Thread Alexander Muriy
Hi Maris and all. is already in my github repository ( https://raw.github.com/amuriy/GRASS-scripts/master/r.split.line) and on GRASS AddOns wiki page ( http://grass.osgeo.org/wiki/GRASS_AddOns#r.split.line). 2012/8/23 Maris Nartiss > Hello Alexander, > if You are not willing to make it into