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 GeoTiffs are detected with wrong location
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chis

New Zealand
8 Posts

Posted - 27/02/2013 :  08:04:03  Show Profile  Reply with Quote
I have a normal GeoTiff with location in New Zealand. Previously this opened fine in OkMap and I could generate KMZ or JNX files that with correct location.

Now when I open the same GeoTiff it thinks I'm in Italy and that's the location recorded for any generated files.

This problem could well be related to my previous issues loading a GeoTiff ffrom a different source that needed to be opened as Lat/Long. But if I open the problem file as meters, north is correct. If I open it as lat/long then north is wrong. I've probably got some funny setting somewhere, but I'm not aware of changing anything.

Here's a link to an image of OkMap showing an incorrect GeoCode of northern Italy:
https://docs.google.com/file/d/0B551NemEg4VsT0NBbk05UjJiS2M/edit?usp=sharing

Here's a link to the same location on a web site at location Latitude -44.732911, Longitude 168.059486:
http://www.topomap.co.nz/NZTopoMap?v=2&ll=-44.732911,168.059486&z=14
(Latitude -44.732911, Longitude 168.059486)

The TIF file is correctly located on other applications, and used to work with OkMap. It's 140MB so I'd prefer not to upload it. I'm hoping there's something obvious about the different locations.

chis

New Zealand
8 Posts

Posted - 27/02/2013 :  08:15:11  Show Profile  Reply with Quote
Information screen as I load:
Geotiff_Information:
Version: 1
Key_Revision: 1.0
Tagged_Information:
ModelTiepointTag (2,3):
0.5 0.5 0
1204000 5046000 0
ModelPixelScaleTag (1,3):
4.233 4.233 0
End_Of_Tags.
Keyed_Information:
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,65): "Edition 1.01 Published 2010 Revised for selected changes in 2010"
GeogGeodeticDatumGeoKey (Short,1): User-Defined
GeogEllipsoidGeoKey (Short,1): Ellipse_GRS_1980
ProjectedCSTypeGeoKey (Short,1): User-Defined
PCSCitationGeoKey (Ascii,48): "New Zealand Transverse Mercator 2000; NZGD 2000"
ProjectionGeoKey (Short,1): User-Defined
ProjCoordTransGeoKey (Short,1): CT_TransverseMercator
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
ProjNatOriginLongGeoKey (Double,1): 173
ProjNatOriginLatGeoKey (Double,1): 0
ProjFalseEastingGeoKey (Double,1): 1600000
ProjFalseNorthingGeoKey (Double,1): 10000000
ProjScaleAtNatOriginGeoKey (Double,1): 0.9996
End_Of_Keys.
End_Of_Geotiff.

Projection Method: CT_TransverseMercator
ProjNatOriginLatGeoKey: 0.000000 ( 0d 0' 0.00"N)
ProjNatOriginLongGeoKey: 173.000000 (173d 0' 0.00"E)
ProjScaleAtNatOriginGeoKey: 0.999600
ProjFalseEastingGeoKey: 1600000.000000
ProjFalseNorthingGeoKey: 10000000.000000
Ellipsoid: 7019/GRS 1980 (6378137.00,6356752.31)
Projection Linear Units: 9001/metre (1.000000m)

Corner Coordinates:
Upper Left (1203997.884,5046002.116) (168d 0'27.61"E, 44d37'48.41"S)
Lower Left (1203997.884,5010000.452) (167d58'46.87"E, 44d57'10.70"S)
Upper Right (1228003.227,5046002.116) (168d18'33.33"E, 44d38'34.55"S)
Lower Right (1228003.227,5010000.452) (168d16'58.62"E, 44d57'57.35"S)
Center (1216000.555,5028001.284) (168d 8'41.72"E, 44d47'53.13"S)
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okmap

Italy
2645 Posts

Posted - 27/02/2013 :  09:01:06  Show Profile  Visit okmap's Homepage  Reply with Quote
Hi Chis, thank you for your reporting but I need an example map to do some tests. Can you upload that map or a little one for me?
Thank you.
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chis

New Zealand
8 Posts

Posted - 27/02/2013 :  20:41:19  Show Profile  Reply with Quote
Sorry, I can't find a small one quickly.

Here's the full size file (138MB) from the source site:
http://topo.linz.govt.nz/Topo50_raster_images/GeoTIFFTopo50/CB08_GeoTifv1-02.tif
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okmap

Italy
2645 Posts

Posted - 28/02/2013 :  08:05:39  Show Profile  Visit okmap's Homepage  Reply with Quote
Thanks, a little patience to analyze it.
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okmap

Italy
2645 Posts

Posted - 28/02/2013 :  08:49:20  Show Profile  Visit okmap's Homepage  Reply with Quote
Follow these steps:
1. Rename the extension of your map from .tiff to .tif
2. File - Load - Map and change format into GeoTiff (*.tif)
3. See map information and press "Next" button
4. Leave default "Metric" unit of measure
5. Type "New Zealand" in country filter and choose "NZGD2000 / New Zealand Transverse Mercator 2000" predefined projection/datum and press "Ok" button.
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chis

New Zealand
8 Posts

Posted - 17/03/2013 :  08:34:31  Show Profile  Reply with Quote
Excellent, works beautifully now.

Worth including a small help file describing how to choose the right values for a given file?
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okmap

Italy
2645 Posts

Posted - 17/03/2013 :  09:37:40  Show Profile  Visit okmap's Homepage  Reply with Quote
It would be nice but unfortunately there are no rules.
The datum/projection are generally printed at the edge of the map.
But if you have a GeoTiff file (your case) you can determine them (with a little experience) looking at the info page displayed by OkMap.
However a great help is to type the country to filter the possible values assignable to the map.
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