Australian Grid Conversion Problem
Ken Cross
Global Mapper User
I am using Global Mapper version 14.1.2. Prior to attempting to change the projection of some georeferenced raster images of parts of South Australia from AMG (AGD66) to MGA (GDA94) I checked the how well the Coordinate Converter tool converted a point from AMG to MGA. Even before entering the coordinates of the point I was concerned by the lack of an input field for the UTM Zone. The conversion should add about 129 metres to the easting and 171 metres to the northing at the location of the point (MGA Zone 53 640000E 6400000N). Instead it added about 72m to the easting and about 40m to the northing. Can I have confidence that the Configuration|Projection tool (which does enable the zone to be specified) will do a better job than the Coordinate converter tool?
Ken
Ken
Comments
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Ken,
When you select UTM there should be a Zone field regardless of whether you are in the Coordinate Convertor of transforming an image on the Configuration dialog. How did you set the datum for the input and output in the Coordinate Convertor when setting up the projections there?
Thanks,
Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.bluemarblegeo.com/ -
global_mapper wrote: »Ken,
When you select UTM there should be a Zone field regardless of whether you are in the Coordinate Convertor of transforming an image on the Configuration dialog. How did you set the datum for the input and output in the Coordinate Convertor when setting up the projections there?
Thanks,
Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.bluemarblegeo.com/
Thanks Mike,
I'm sorry to have bothered you. I was in a rush to get one particular conversion done and I made an incorrect selection of "Transverse Mercator (South Oriented)". In this projection the "Zone" field is not selectable. When the correct projection, "UTM", is selected, the "Zone" is selectable and the resultant coordinate conversion is accurate. My apology for not more thoroughly checking back over what I had done before posting.....embarrassing :mad:!
Regards,
Ken
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