[Gdal-dev] Defining Australian Map Grid in GDAL

Tue Feb 28 20:09:38 EST 2006

Thanks for the advice Jacob and Frank.

Still having some trouble though. I use the images in Mapinfo. They were provided with world files and Mapinfo TAB file for registration.

 I use a tool called MapImagery to open GeoTiffs in Mapinfo. It reads the header of the Geotiff and facilitates the registration process in Mapinfo.

In the case of the original file if I open it with MapImagery it describes the datum projection and units for the file eg WGS84/UTM/meters

After doing a GDAL_translate using the details provided by Jacob and defining a new ULLR I get RAW/RAW/RAW and the ULLR bounds are ignored.

However GDALINFO and LISTGEO correctly returns the header information I've set.

GDALWARP also continues to fail when overriding the source.

Original image header
Driver: GTiff/GeoTIFF
Size is 3120, 4100
Coordinate System is `'
Origin = (761888.499025,6109620.810466)
Pixel Size = (3.62093253,-3.62093253)
Metadata:
  TIFFTAG_XRESOLUTION=175
  TIFFTAG_YRESOLUTION=175
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Corner Coordinates:
Upper Left  (  761888.499, 6109620.810) 
Lower Left  (  761888.499, 6094774.987) 
Upper Right (  773185.809, 6109620.810) 
Lower Right (  773185.809, 6094774.987) 
Center      (  767537.154, 6102197.899) 

Modified image header using GDAL_Translate 
Driver: GTiff/GeoTIFF
Size is 3120, 4100
Coordinate System is:
PROJCS["UTM Zone 55, Southern Hemisphere",
    GEOGCS["Australian Natl & S. Amer. 1969",
        DATUM["unknown",
            SPHEROID["unnamed",6378160,298.249999999996]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",147],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",10000000],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (761888.500000,6109620.810000)
Pixel Size = (3.62093269,-3.62093171)
Metadata:
  AREA_OR_POINT=Area
  TIFFTAG_SOFTWARE=IrfanView
  TIFFTAG_XRESOLUTION=175
  TIFFTAG_YRESOLUTION=175
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Corner Coordinates:
Upper Left  (  761888.500, 6109620.810) (149d52'25.73"E, 35d 7'19.61"S)
Lower Left  (  761888.500, 6094774.990) (149d52'42.71"E, 35d15'20.92"S)
Upper Right (  773185.810, 6109620.810) (149d59'51.49"E, 35d 7'8.81"S)
Lower Right (  773185.810, 6094774.990) (150d 0'9.20"E, 35d15'10.06"S)
Center      (  767537.155, 6102197.900) (149d56'17.28"E, 35d11'14.91"S)

	-----Original Message----- 
	From: Delfos, Jacob [mailto:jacob.delfos at maunsell.com] 
	Sent: Wed 3/1/2006 11:02 AM 
	To: Andrew Williams 
	Cc: gdal-dev at lists.maptools.org 
	Subject: RE: [Gdal-dev] Defining Australian Map Grid in GDAL

	Andrew, 

	You have to be careful with AGD-based projections in Proj4, because the definitions that exist in Proj4 are not correct (problem with datums). I'm attaching a file with correct definitions for AGD-based projections. I have myself spent several days trying to figure out why my coordinates were up to 200m off, only to realise that Proj4 does not appear to use the AGD84 and AGD66 datum correctly.

	Just for the record: 
	AMG66 = UTM + AGD66-datum 
	AMG84 = UTM + AGD84-datum 
	MGA94 = UTM + GDA94-datum (where GDA94 can be substituted with WGS84) 

	Be careful with the acronyms. You wouldn’t be the first to start construction in the wrong spot :) 
	For your image, I guess just override the projection, and project from Latlong AGD84 (epsg:4203, bottom of file I sent) to Latlong WGS84.

	Regards, 

	Jacob 

	JACOB DELFOS
	GIS ANALYST
	Maunsell Australia Pty Ltd
	629 Newcastle Street, Leederville, WA 6007 
	PO Box 81, Leederville, WA 6902 
	Western Australia 
	ABN 20 093 846 925

	Tel     + 61 8 9281 6185
	Fax    + 61 8 9281 6297
	jacob.delfos at maunsell.com 

	<<agd84_agd66_proj4.txt>> 

	» -----Original Message----- 
	» From: gdal-dev-bounces at lists.maptools.org 
	» [mailto:gdal-dev-bounces at lists.maptools.org <mailto:gdal-dev-bounces at lists.maptools.org> ] On Behalf Of 
	» Andrew Williams 
	» Sent: 28 February 2006 22:27 
	» To: gdal-dev at lists.maptools.org 
	» Subject: [Gdal-dev] Defining Australian Map Grid in GDAL 
	» 
	» Hello folks. 
	» I'm having trouble with a Geotiff. 
	» The scan is a topographic map sheet. The cartography and grid 
	» on the sheet is based on AMG (Australian Map Grid). It is a 
	» UTM projection based on the Australian National Spheroid, 
	» ellps=aust_SA I believe. 
	»  
	» My problem is that the GeoTiff has been georefernced as UTM 
	» ellps=GRS80 datum=WGS84 incorrectly. 
	»  
	» My intent is to gdalwarp the image to latlong WGS84. 
	»  
	» I have tried for the better part of a day to attempt to 
	» override or otherwise correct the georeferncing. Without success. 
	»  
	» I have been very successful with GDAL in the past, but this 
	» has stopped me. 
	»  
	» The problem is that I can't seem to fully define AMG "enough" 
	» to allow GDALwarp to reproject the image. It seems to default 
	» to the source as being UTM WGS84. 
	»  
	» I attempted to gdal_translate the image using the corrected 
	» definition and then gdalwarp image, but that also failed. 
	»  
	» the definition I have been using is "+proj=tmerc 
	» +ellps=aust_SA +lat_0=0 +lon_0=147 +x_0=500000 +y_0=10000000 
	» +k=0.9996 +south" 
	»  
	» regards 
	» Andrew 
	» 
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