Hi Helmut,<br><br><div class="gmail_quote">On Sun, Jul 15, 2012 at 10:14 PM, Helmut Kudrnovsky <span dir="ltr"><<a href="mailto:hellik@web.de" target="_blank">hellik@web.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>using GDAL Virtual Format [1] by building a virtual dataset by gdalbuildvrt?<br>
<br>
it's really a nice gdal utility:<br>
<br>
no need to patch all ASTER GDEM tiles within grass, just import the virtual<br>
dataset by r.in.gdal or link it by r.external<br>
<br>
<br>
[1] <a href="http://www.gdal.org/gdal_vrttut.html" target="_blank">http://www.gdal.org/gdal_vrttut.html</a><br>
[2] <a href="http://www.gdal.org/gdalbuildvrt.html" target="_blank">http://www.gdal.org/gdalbuildvrt.html</a><br>
<br clear="all"></blockquote></div><br>I decided to follow your hint and explore the way of gdalbuildvrt. I'm using:<br><br>gdalbuildvrt -input_file_list /home/leomarg/Desktop/aster/elenco_aster_europa \<br>/home/leomarg/Desktop/aster/mosaic.vrt <br>
<br>and the process takes only few seconds, without complaining. The problem raises when i try to import it in GRASS:<br><br>r.external input=/home/leomarg/Desktop/aster/mosaic.vrt output=mosaic<br><br>Projection of input dataset and current location appear to match<br>
Importing band 1 of 1...<br>ERROR 4: `ASTGTM_N33E000_dem_lzw.tif' does not exist in the file system,<br>and is not recognised as a supported dataset name.<br><br>Link to raster map <mosaic> created<br><br><a href="http://r.info">r.info</a> map=mosaic<br>
 +----------------------------------------------------------------------------+<br> | Layer:    mosaic                         Date: Tue Jul 17 15:43:08 2012    |<br> | Mapset:   PERMANENT                      Login of Creator: leomarg         |<br>
 | Location: ASTER_GDEM                                                       |<br> | DataBase: /forest/GRASS/grassdata                                          |<br> | Title:     ( mosaic )                                                      |<br>
 | Timestamp: none                                                            |<br> |----------------------------------------------------------------------------|<br> |                                                                            |<br>
 |   Type of Map:  raster               Number of Categories: 0               |<br> |   Data Type:    CELL                                                       |<br> |   Rows:         140401                                                     |<br>
 |   Columns:      198001                                                     |<br> |   Total Cells:  27799538401                                                |<br> |        Projection: Latitude-Longitude                                      |<br>
 |            N: 72:00:00.5N    S: 32:59:59.5N   Res: 0:00:01                 |<br> |            E: 44:00:00.5E    W: 11:00:00.5W   Res: 0:00:01                 |<br> |   Range of data:    min = 0  max = 0                                       |<br>
 |                                                                            |<br> |   Data Description:                                                        |<br> |    generated by r.external                                                 |<br>
 |                                                                            |<br> |   Comments:                                                                |<br> |    r.external input="/home/leomarg/Desktop/aster/mosaic.vrt" output="mo\   |<br>
 |    saic"                                                                   |<br> |                                                                            |<br> +----------------------------------------------------------------------------+<br>
<br>what am i missing?<br><br>Thanks!<br><br><br>-- <br><span style="color:rgb(102,102,102)">Dr. Margherita Di Leo</span><font color="#666666"><br></font><span style="color:rgb(102,102,102)"></span><br><br><br>