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:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><title>Re:
[GRASS-user] Export of GeoTIFF</title> <font face="Verdana, Helvetica, Arial"><span style="font-size: 12px;">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> </span></font><blockquote><font face="Verdana, Helvetica, Arial"><span style="font-size: 12px;"><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> </span></font></blockquote><font face="Verdana, Helvetica, Arial"><span style="font-size: 12px;"><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/%7Ecmbarton">http://www.public.asu.edu/~cmbarton</a> <br> <br> </span></font> _______________________________________________<br>grassuser mailing list<br>grassuser@grass.itc.it<br>http://grass.itc.it/mailman/listinfo/grassuser<br></blockquote><br><BR><BR>your sincerely<br><br>alf<br>-_-____02053<p> 
<hr size=1>Building a website is a piece of cake. <br>Yahoo! Small Business gives you <a href="http://us.rd.yahoo.com/evt=48251/*http://smallbusiness.yahoo.com/webhosting/?p=PASSPORTPLUS">all the tools to get online.</a>