Stefan, I think you do understand the problem as I've described it and I think I am following your geo-speak.
The polygons are primarily 3x9 foot spaces in a ~100 acre cemetery. So, accuracy within a few inches would be ideal (though I agree this will be a TALL order and likely require the rest of my life gathering sample points). If that's impossible, something closer than what I have right now would be nice. I'll look into warping and also affine-transforms and see if I can speak more intelligently about what my specific problems are and how to go about fixing them. Thanks for the help! Stefan Steiniger wrote: > 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? >> _______________________________________________ >> jump-users mailing list >> [email protected] >> http://lists.refractions.net/mailman/listinfo/jump-users >> >> NIWA is the trading name of the National Institute of Water & >> Atmospheric Research Ltd. >> _______________________________________________ >> jump-users mailing list >> [email protected] >> http://lists.refractions.net/mailman/listinfo/jump-users >> >> > _______________________________________________ > jump-users mailing list > [email protected] > http://lists.refractions.net/mailman/listinfo/jump-users _______________________________________________ jump-users mailing list [email protected] http://lists.refractions.net/mailman/listinfo/jump-users
