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<TITLE>Re: [GRASS-user] Export of GeoTIFF</TITLE>
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<FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>You can get GRASS data into ArcView/ArcGIS much more simply than this.<BR>
<BR>
Vector: use v.out.ogr to export to a shape file<BR>
<BR>
Raster: use r.out.arc OR r.out.gdal to export to an ESRI ASCII grid file<BR>
<BR>
<BR>
Michael<BR>
<BR>
On 10/10/07 3:56 PM, "al furqon lebo" <alf_lebo@yahoo.com> wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>GRASS Data To ArcView<BR>
This document will show the procedure to export GRASS raster and vector data to<BR>
ArcView.<BR>
GRASS Vector Data to ArcView 2.1/3.0<BR>
1) In GRASS use the v.out .ascii command on the vector file you wish to export.<BR>
2) In GRASS use the v.out.dxf command on the ascii file you created above. When<BR>
GRASS prompts you for a dxf file name, type in the name with extension(i.e.<BR>
soils.dxf). The .dxf extension will be needed for ArcView.<BR>
Please note that dxf files can only be displayed in ArcView 2.1(MS Windows) and<BR>
ArcView 3.0(UNIX and MS Windows).<BR>
3) To display the dxf file in ArcView you first need to open a VIEW then add a<BR>
theme(Feature Data Source). The dxf file should be selectable on the screen. Open<BR>
the dxf file. You have to convert the dxf file to a shapefile in order to change<BR>
projection etc.<BR>
GRASS Raster Data To ArcView 2.1/3.0<BR>
This procedure will georeference a raster image within ArcView!<BR>
1) In GRASS use the r.out.tiff command on the Raster file you wish to export. Use<BR>
defaults for the command! In particular DO NOT use the LZW compression! This<BR>
may make your file unreadable in ArcView. The GRASS generated TIFF file should<BR>
have a tiff extention(i.e. photo1.tif)<BR>
2) After making the TIFF file goto your "cellhd" sub-directory!<BR>
3) Cat the raster cellhd file you exported! You will use the information in this file to<BR>
build a world file. A world file is a ascii file ArcView uses to georeference information<BR>
for the TIFF file you created. With the world file your TIFF file will be georeference in<BR>
ArcView.<BR>
4) Start a vi session, name the file the same as your TIFF file except with a different<BR>
extention! Use the extention .tfw (i.e. photo1.tfw ). You will enter six lines of<BR>
information in your vi session. You can use this file as a base for future world file.<BR>
Below is the possible contents of a typical world file.<BR>
10.0<BR>
0.0<BR>
0.0<BR>
-10.0<BR>
590005<BR>
4927995<BR>
Below is the possible contents of a typical GRASS cellhd file.<BR>
proj: 1<BR>
zone: 16<BR>
north: 4928000.000000<BR>
south: 4914000.000000<BR>
west: 590000.000000<BR>
east: 609000.000000<BR>
n-s resol: 10.000000<BR>
e-w resol: 10.000000<BR>
format: 1<BR>
compressed: 0<BR>
Below is the information you will need to create the above world file(tfw). Please note<BR>
that the world file contains information in your GRASS cellhd file! Information on the<BR>
world file can be found in ArcView 3.0 manual on page 301.<BR>
World File GRASS Cellhd File Description<BR>
10.0 "e-w resol:" Size of pixel in x direction.<BR>
0.0 N\A Rotation term for row(usually 0).<BR>
0.0 N\A Rotation term for column(usually 0).<BR>
-10.0 "n-s resol:" Size of pixel in y direction(- sign is needed!)<BR>
590005 "west" + 1/2 "e-w resol" The x coordinate of pixel in upper left corner. *<BR>
4927995 "north" - 1/2 "n-s resol" The y coordinate of pixel in upper left corner. *<BR>
Pixel 1,1 * ArcView georeferences the center of the pixel while GRASS<BR>
uses the NW edge in the cellhd file. Thus a slight adjustment is<BR>
needed to correctly georeference a TIFF file in ArcView. For these<BR>
lines you need to add one half the pixel resolution(west) and subtract<BR>
one half the pixel resolution(north).<BR>
5) Place your TIFF and world file in the same directory. These files now can be used<BR>
in ArcView and should be georeferenced correctly!.<BR>
A sample world file call be found at the NCG FTP Site! The NCG FTP is listed below.<BR>
ftp.ftw.nrcs.usda.gov (goto the /outgoing directory! and get the file "base.tfw")<BR>
If You have any questions please contact me at your convenience.<BR>
Tony Kimmet<BR>
(817)-334-5212 x3062<BR>
tkimmet@ftw.nrcs.usda.gov<BR>
<BR>
<B><I>Michael Barton <michael.barton@asu.edu></I></B> wrote:<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>Re: [GRASS-user] Export of GeoTIFF ESRI needs special GeoTiff options to be enabled. These are documented on the r.out.gdal manual page--near the bottom where I missed them too awhile back.<BR>
<BR>
Michael<BR>
<BR>
<BR>
On 10/9/07 11:58 PM, "christian.braun@tudor.lu" <christian.braun@tudor.lu> wrote:<BR>
<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'><BR>
Dear list, <BR>
<BR>
I have serious problems exporting GRASS DCELL rasters to GeoTIFF. <BR>
I used r.out.gdal with type=Float32 and set the compression to LZW. <BR>
What I got later on in ArcView 3.3 is pure noise fort he picture and in ArcGIS 9.2 I get some strange results. <BR>
The NULL values of the picture get a cryptic code like -1#QUAN1 and if there are pixels with value 0 they become NoData in ArcGIS. <BR>
<BR>
I need to have them as GeoTIFFs for the easy im- and export. I am aware that I can also use r.out.ascii but then I have to do an import procedure in ArcGIS. For nearly 1000 images that is a bit hard to do. <BR>
<BR>
Any hints for the export options? <BR>
<BR>
Thx in advance, <BR>
Christian <BR>
<BR>
<BR>
_________________________________________<BR>
<BR>
Dipl. Geogr. Christian Braun<BR>
Tel: +352- 425991-608<BR>
Mobil: +49-179-6845896<BR>
Mail: christian.braun@tudor.lu<BR>
<BR>
Resource Centre for Environmental Technologies,<BR>
Public Research Centre Henri Tudor,<BR>
Technoport Schlassgoart,<BR>
66 rue de Luxembourg,<BR>
P.O. BOX 144,<BR>
L-4002 Esch-sur-Alzette, Luxembourg<BR>
<BR>
</SPAN></FONT></BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'><BR>
<BR>
__________________________________________<BR>
Michael Barton, Professor of Anthropology<BR>
Director of Graduate Studies<BR>
School of Human Evolution & Social Change <BR>
Center for Social Dynamics & Complexity<BR>
Arizona State University<BR>
<BR>
phone: 480-965-6213<BR>
fax: 480-965-7671<BR>
www: <a href="http://www.public.asu.edu/~cmbarton">http://www.public.asu.edu/~cmbarton</a> <a href="http://www.public.asu.edu/%7Ecmbarton"><http://www.public.asu.edu/%7Ecmbarton></a> <BR>
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<BR>
your sincerely<BR>
<BR>
alf<BR>
-_-____02053<BR>
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</SPAN></FONT></BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'><BR>
<BR>
__________________________________________<BR>
Michael Barton, Professor of Anthropology <BR>
Director of Graduate Studies<BR>
School of Human Evolution & Social Change <BR>
Center for Social Dynamics and Complexity<BR>
Arizona State University<BR>
<BR>
phone: 480-965-6213<BR>
fax: 480-965-7671<BR>
www: <a href="http://www.public.asu.edu/~cmbarton">http://www.public.asu.edu/~cmbarton</a> <BR>
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