Hei Kurt,
yeah.. I am also not quite sure how to help you.
However, if you have reference points that are in your target coordinate
system an in the dataset that you would like to transform, then you
could try to use the Affine-Transformation Tool (>Tools>Transform). I
think a HowTo can be found in one of the original JUMP documentations.
However, I am not realy sure if that brings you the accuracy you need,
i.e. you didn't wrote
- what is your current Coordinate/Cartographic Projection System (is it
in meters or in lat/lon = degrees?, is it GPS data)
- what is your target Coordinate/Cartographic Projection System (short
sometimes: CRS for Coordinate Reference System),
- what transformation accuracy is needed (m, submeter, 100m?)
- ... ?I forgot that? ...
to develop/use a transformation procedure would depend on all those things.
Sorry, I may have chosen a bit a too technical language - but this is
somehow not avoidable with respect to your question (and if I understood
it correctly)
stefan
Brent Wood schrieb:
Hi Kurt,
If you can work out what the projection system is for your data, then Proj.4
can do the conversion for you.
Note that it is likely to be easier to use ogr2ogr (part of GDAL) as this can
use the proj.4 libraries to reproject data, but can also read/write shapefiles
so you could generate reprojected shapefiles directly from your original
shapefile.
The key to thi working is knowing the coordinate reference system of your
source data.
If this infomation is not available, then some sort of manual coordinate
transformation may be possible, based on your suggested approach of working
from visually determined points, but I'd use this approach as a last resort,
especially if any sort of accuracy is required.
see: http://www.gdal.org/
Cheers,
Brent Wood
Brent Wood
DBA/GIS consultant
NIWA, Wellington
New Zealand
Kurt Heston <[email protected]> 05/11/09 10:22 AM >>>
I've inherited a set of shape files that are not georeferenced. The
upper left corner of the extent is on 0/0 lat/lon. So, when I try to
view them after translating to KML, for example, they show up in the
middle of the Atlantic Ocean.
Is there any way in OpenJump that I can fix them? There's about a 130k
polygons involved with lots of attributes that I'd like to forego
re-creating if I can.
If I use a survey-grade GPS or Google Earth to match a bunch of points
in these shapefiles to their true locations on Earth, can something
move/stretch/skew/scale them to their earthly positions? This HAS to
have been done at some point with all the non-geo CAD stuff that existed
b4 geo-spatial tooling took hold, right?
I'm hoping there's a tool I've missed (in much Googling) that I can use
to correlate the two. I'm guessing that if such a tool is available,
it's going to take A LOT of point matches to fix the files, but that
scares me less than re-creating the data in its entirety.
Can anyone send me in the right direction here?
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