[Qgis-user] reference raster layers

Michael Neubauer Neubauer-Michael at gmx.net
Wed Oct 8 12:29:52 PDT 2008


Hello Bernando,

first: When you change the projection (or better "spatial reference system") 
in the project properties, it does not change the "spatial reference system" 
in the data of your layer. Transforming your data to another "spatial 
reference system" would be a more complicated operation.
But the good thing is, that with OTF activated, you do not have to do that and 
you can superpone layers in different "spatial reference systems".
So do not wonder that the projection of your layer stays the same, when you 
change the projection of the whole project. Changing the projection of the 
whole project should only have an effect on the coordinates which are 
displayed (right bottom of the screen)

second: UTM is a "projected coordinate system" in contrast to "geographic 
coordinate systems". "Geographic coordinate systems" treat the earth like a 
sphere and work with degrees. "Projected coordinate systems" project the 
spere (ball earth :-) ) on a flat surface and deal with other numbers, which 
are defined in each coordinate system differently.
UTM stands for "Universal Transverse Mercator" and you find it at the bottom 
of "projected coordinate systems" in QGIS (between "geographic coordinate 
systems" and "user defined coordinate systems").
So you have to look for "WGS84 / UTM zone 32N" --> N for northern hemisphere.

So I hope that practical and theoretical information helps...  :-)
Let me know if everything works

bye
michael



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