[Proj] PROJ.4 and local coordinate systems

[joeri.theelen]

Janne,

Thanks for trying to help me out. Working with datum definitions is what I
tried to avoid in the first place, as I thought it would be too complex and
not accurate anough for the kind of data I am working with (high precision
and very large scale). Following the advise from another reply to my
question, I found a module to transform coordinates from one system to
another (in SAGA GIS). This has nothing to do with "real" coordinate
transformations, but it is exacly what I need.

Kind regards,
Joeri


support.mn wrote:
> 
> Hello,
> 
>> By transformation, I
>> mean translation, rotation and dilation (scale factor) of the X/Y
>> coordinates only, not height.
> 
> there is the possibility to use datums. What you just wrote is a datum
> definition. You define a datum for both systems relative to the wgs84
> and proj-4 should automatically transform your coordinates.. ??
> 
> if the coordinate values do not match to any standard, just define your
> own false easting and false northing values so that the resulting values
> are better.. ??
> 
> Regards: Janne.
> 
> -------------------------------------
> 
> "joeri.theelen" <joeri.theelen at arts.kuleuven.be> kirjoitti: 
>> 
>> Hi,
>> 
>> Is it possible to use PROJ.4 or any of its related tools to transform
>> coordinates from a local carthesian system into another local carthesian
>> system (thus both are not earth related).
>> 
>> I inherit lots of datasets in many different formats for an
>> archaeological
>> site, with coordinates measured in two different local systems (shift in
>> time). I managed to get the transformation parameters to transform sets
>> of
>> coordinates between both systems, with minor error. By transformation, I
>> mean translation, rotation and dilation (scale factor) of the X/Y
>> coordinates only, not height.
>> 
>> I also managed to get the transformation parameters from both local
>> systems
>> to the UTM system in use in that area. Thus, transforming from local to
>> UTM
>> to local would be an option as well.
>> 
>> Can anybody help me with this? I know programming such a tranformation
>> would
>> be trivial, but I need the power and flexibility of a tool like "cs2cs"
>> to
>> cope with the many different formats I am facing.
>> 
>> Thank you,
>> Joeri
>> -- 
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