[GRASS-user] Export of GeoTIFF
Gerald Nelson
gnelson at uiuc.edu
Wed Oct 10 20:30:16 EDT 2007
Any chance this could be added to the Grass wiki as a FAQ? Thanks, Jerry
---- Original message ----
>Date: Wed, 10 Oct 2007 15:56:43 -0700 (PDT)
>From: al furqon lebo <alf_lebo at yahoo.com>
>Subject: Re: [GRASS-user] Export of GeoTIFF
>To: Michael Barton <michael.barton at asu.edu>, christian.braun at tudor.lu, grassuser at grass.itc.it
>
> GRASS Data To ArcView
> This document will show the procedure to export
> GRASS raster and vector data to
> ArcView.
> GRASS Vector Data to ArcView 2.1/3.0
> 1) In GRASS use the v.out .ascii command on the
> vector file you wish to export.
> 2) In GRASS use the v.out.dxf command on the ascii
> file you created above. When
> GRASS prompts you for a dxf file name, type in the
> name with extension(i.e.
> soils.dxf). The .dxf extension will be needed for
> ArcView.
> Please note that dxf files can only be displayed in
> ArcView 2.1(MS Windows) and
> ArcView 3.0(UNIX and MS Windows).
> 3) To display the dxf file in ArcView you first need
> to open a VIEW then add a
> theme(Feature Data Source). The dxf file should be
> selectable on the screen. Open
> the dxf file. You have to convert the dxf file to a
> shapefile in order to change
> projection etc.
> GRASS Raster Data To ArcView 2.1/3.0
> This procedure will georeference a raster image
> within ArcView!
> 1) In GRASS use the r.out.tiff command on the Raster
> file you wish to export. Use
> defaults for the command! In particular DO NOT use
> the LZW compression! This
> may make your file unreadable in ArcView. The GRASS
> generated TIFF file should
> have a tiff extention(i.e. photo1.tif)
> 2) After making the TIFF file goto your "cellhd"
> sub-directory!
> 3) Cat the raster cellhd file you exported! You will
> use the information in this file to
> build a world file. A world file is a ascii file
> ArcView uses to georeference information
> for the TIFF file you created. With the world file
> your TIFF file will be georeference in
> ArcView.
> 4) Start a vi session, name the file the same as
> your TIFF file except with a different
> extention! Use the extention .tfw (i.e. photo1.tfw
> ). You will enter six lines of
> information in your vi session. You can use this
> file as a base for future world file.
> Below is the possible contents of a typical world
> file.
> 10.0
> 0.0
> 0.0
> -10.0
> 590005
> 4927995
> Below is the possible contents of a typical GRASS
> cellhd file.
> proj: 1
> zone: 16
> north: 4928000.000000
> south: 4914000.000000
> west: 590000.000000
> east: 609000.000000
> n-s resol: 10.000000
> e-w resol: 10.000000
> format: 1
> compressed: 0
> Below is the information you will need to create the
> above world file(tfw). Please note
> that the world file contains information in your
> GRASS cellhd file! Information on the
> world file can be found in ArcView 3.0 manual on
> page 301.
> World File GRASS Cellhd File Description
> 10.0 "e-w resol:" Size of pixel in x direction.
> 0.0 N\A Rotation term for row(usually 0).
> 0.0 N\A Rotation term for column(usually 0).
> -10.0 "n-s resol:" Size of pixel in y direction(-
> sign is needed!)
> 590005 "west" + 1/2 "e-w resol" The x coordinate of
> pixel in upper left corner. *
> 4927995 "north" - 1/2 "n-s resol" The y coordinate
> of pixel in upper left corner. *
> Pixel 1,1 * ArcView georeferences the center of the
> pixel while GRASS
> uses the NW edge in the cellhd file. Thus a slight
> adjustment is
> needed to correctly georeference a TIFF file in
> ArcView. For these
> lines you need to add one half the pixel
> resolution(west) and subtract
> one half the pixel resolution(north).
> 5) Place your TIFF and world file in the same
> directory. These files now can be used
> in ArcView and should be georeferenced correctly!.
> A sample world file call be found at the NCG FTP
> Site! The NCG FTP is listed below.
> ftp.ftw.nrcs.usda.gov (goto the /outgoing directory!
> and get the file "base.tfw")
> If You have any questions please contact me at your
> convenience.
> Tony Kimmet
> (817)-334-5212 x3062
> tkimmet at ftw.nrcs.usda.gov
>
> Michael Barton <michael.barton at asu.edu> wrote:
>
> 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.
>
> Michael
>
> On 10/9/07 11:58 PM, "christian.braun at tudor.lu"
> <christian.braun at tudor.lu> wrote:
>
> Dear list,
>
> I have serious problems exporting GRASS DCELL
> rasters to GeoTIFF.
> I used r.out.gdal with type=Float32 and set the
> compression to LZW.
> 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.
> 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.
>
> 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.
>
> Any hints for the export options?
>
> Thx in advance,
> Christian
>
> _________________________________________
>
> Dipl. Geogr. Christian Braun
> Tel: +352- 425991-608
> Mobil: +49-179-6845896
> Mail: christian.braun at tudor.lu
>
> Resource Centre for Environmental Technologies,
> Public Research Centre Henri Tudor,
> Technoport Schlassgoart,
> 66 rue de Luxembourg,
> P.O. BOX 144,
> L-4002 Esch-sur-Alzette, Luxembourg
>
> __________________________________________
> Michael Barton, Professor of Anthropology
> Director of Graduate Studies
> School of Human Evolution & Social Change
> Center for Social Dynamics & Complexity
> Arizona State University
>
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
>
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>
> your sincerely
>
> alf
> -_-____02053
>
>
>
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Gerald Nelson
Professor, Dept. of Agricultural and Consumer Economics
University of Illinois, Urbana-Champaign
office: 217-333-6465
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