[Qgis-user] Coordinates in map units are different between ArcInfo and Qgis

[Tudorache, Marian]

Hi everyone,

I have two GIS systems. First one is based on ArcInfo and the other one is based on Qgis 2.10.

The system with ArcInfo uses Esri coverage data files.
QGIS is able to read coverage data but I see differences between the coordinate expressed on map units between the two.

For example:
A point has in ArcInfo the coordinates in map units (meters) x = -1273005.24 and y = 2898383.44.
The same point has in Qgis the coordinates in map units (meters) x = -1940424.5898 and y = 3192159.87877.

I looked in qgsmaptopixel.cpp how the mouse position coordinate is transformed to world map units coordinate and I have found this:
mx = x * mMapUnitsPerPixel + xMin
my = -1 * ((y – yMax) * mMapUnitsPerPixel – Ymin)

I have displayed the transformation parameters in Qgis using showParameters function and I got:
Map units/pixel: 6130.91 center: -337918, 1.36002e+06 rotation: 0, size: 1493x974
So it looks a pixel has 6130.91 meters.
Map center is located at -337918, 1.36002e+06 (probably meters)
I can’t figure out the value for xMax, xMin , yMax, yMin.

Can somebody explain me why coordinates in map units read by Qgis are different than those read by ArcInfo?
How can I make the two coordinates to be the same?
Thanks,
Marian

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