[maplab-users] The right projection for "non eart" objects in MapLab

[Daniel Morissette]

expander@mail.com wrote:
> 
> However I've got another questions: after importing and creating new layers (using previous Mapifo .tab files), I've created a new .map Map File with MapEdit.
> Well, files I've imported aren't georeferenced, which means they have got "non earth" coordinates, using a common Mapinfo definition.
> Moreover these files reference to a different part of the world, specifically to a precise part of Italy (with a linear extension of 200 km).
> In my project I've used default system projection of your tutorial.map file relative, instead, to Lambert Conformal Conic projection for Canada (I suppose).
> The output, in MapBrowser, is a Map file with no formal error but, nothing is visible in the map window: I think my layers are too small or too big for a correct visualisation in the map.
> So, I wonder (if I wan't to georeference my data), if you may suggest which settings (scale, zoom, projection) might I use in this my project.
> Thank you in advance for any help.
> 

If all your data uses the same coordinate system, then you do not need
to define PROJECTIONs at all in your mapfile.  PROJECTIONs are useful
only when you have layers in different projections that you want
MapServer to reproject on the fly to make them display on top of each
other.  Since in your case you don't seem to know the projection of your
data let's first try with the assumption that all data is in the same
projection.

So all you need to do is find out the extents (minx,miny,maxx,maxy) of
your data, and use that for the EXTENT setting at the top-level in the
mapfile.  That should be sufficient if all your data is in the same
coordinate system.  How to find the extents of your data depends on the
tools you have available, if you have MapInfo then you could use that,
otherwise you could probably get this information using ogrinfo.exe that
comes with the GDAL/OGR library at http://www.remotesensing.org/gdal/

I hope that helps,

Daniel
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 Daniel Morissette               morissette@dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
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