A typical output from geotiflib mey look like this:
Geotiff_Information: Version: 1 Key_Revision: 1.0 Tagged_Information: ModelTiepointTag (2,3): 0 0 0 1547250 5415950 0 ModelPixelScaleTag (1,3): 100 100 0 End_Of_Tags. Keyed_Information: GTModelTypeGeoKey (Short,1): ModelTypeProjected GTRasterTypeGeoKey (Short,1): RasterPixelIsArea GeographicTypeGeoKey (Short,1): GCS_DHDN GeogAngularUnitsGeoKey (Short,1): Angular_Degree GeogEllipsoidGeoKey (Short,1): Ellipse_Bessel_1841 GeogSemiMajorAxisGeoKey (Double,1): 6377397.16 GeogSemiMinorAxisGeoKey (Double,1): 6356078.96 GeogInvFlatteningGeoKey (Double,1): 299.152813 ProjectedCSTypeGeoKey (Short,1): Unknown-31468 ProjLinearUnitsGeoKey (Short,1): Linear_Meter End_Of_Keys. End_Of_Geotiff.PCS = 31468 (name unknown)GCS: 4314/(unknown)Ellipsoid: 7004/(unknown) (6377397.16,6356078.96)Projection Linear Units: 9001/metre (1.000000m)Corner Coordinates:Upper Left ( 1547250.000, 5415950.000)Lower Left ( 1547250.000, 941650.000)Upper Right ( 7186450.000, 5415950.000)Lower Right ( 7186450.000, 941650.000)Center ( 4366850.000, 3178800.000)From what I understand ModelTiepointTag will tell me where in an actual map the pixels it identifies are located so in this case pixel 0,0 should be at 1547250, 5415950 (what values are these exactly?).
ModelPixelScaleTag will give me a relation about the images scale in real life. But what exactly do these values mean, and how do I extract a useful value from them (eg this distance in my image is these many meters in real life)?
Corner Coordinates is quite easy to understand, but again I dont know what do those values represent. Can I convert them to latitude longitude values?
If the above was too long, then basically what interests me is to be able to understand how can I correlate the values on the image with the actual world values they represent.
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Geotiff_Information: Version: 1 Key_Revision: 1.0 Tagged_Information: ModelTiepointTag (2,3): 0 0 0 1547250 5415950 0 ModelPixelScaleTag (1,3): 100 100 0 End_Of_Tags. Keyed_Information: GTModelTypeGeoKey (Short,1): ModelTypeProjected GTRasterTypeGeoKey (Short,1): RasterPixelIsArea GeographicTypeGeoKey (Short,1): GCS_DHDN GeogAngularUnitsGeoKey (Short,1): Angular_Degree GeogEllipsoidGeoKey (Short,1): Ellipse_Bessel_1841 GeogSemiMajorAxisGeoKey (Double,1): 6377397.16 GeogSemiMinorAxisGeoKey (Double,1): 6356078.96 GeogInvFlatteningGeoKey (Double,1): 299.152813 ProjectedCSTypeGeoKey (Short,1): Unknown-31468 ProjLinearUnitsGeoKey (Short,1): Linear_Meter End_Of_Keys. End_Of_Geotiff.PCS = 31468 (name unknown)GCS: 4314/(unknown)Ellipsoid: 7004/(unknown) (6377397.16,6356078.96)Projection Linear Units: 9001/metre (1.000000m)Corner Coordinates:Upper Left ( 1547250.000, 5415950.000)Lower Left ( 1547250.000, 941650.000)Upper Right ( 7186450.000, 5415950.000)Lower Right ( 7186450.000, 941650.000)Center ( 4366850.000, 3178800.000)From what I understand ModelTiepointTag will tell me where in an actual map the pixels it identifies are located so in this case pixel 0,0 should be at 1547250, 5415950 (what values are these exactly?).
ModelPixelScaleTag will give me a relation about the images scale in real life. But what exactly do these values mean, and how do I extract a useful value from them (eg this distance in my image is these many meters in real life)?
Corner Coordinates is quite easy to understand, but again I dont know what do those values represent. Can I convert them to latitude longitude values?
If the above was too long, then basically what interests me is to be able to understand how can I correlate the values on the image with the actual world values they represent.
أكثر...