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I have been given a large dataset of X,Y positions of animal movements in a generic grid system. It uses 0,0 as an origin and then position units are in feet from origin. I have the geo-referenced coordinates for the origin of the generic grid in the real world and would like to convert the entire grid to the coordinate system. One complication is that the x-axis of the generic grid is ~-38.4 degrees off of equatorial flat. They used a structure as their x-axis plane. Any tools or techniques that would enable this?

Basically the manufacturer of an animal tracking system dumped this generic X,Y grid on us and I need to overlay with geo-referenced imagery.

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  • If the origin coordinates are in lat/long, could you convert that single point to a more localized coordinate system that is in feet and then add those values to all the X/Y positions of the dataset? (Many state plane systems in the US are available in feet, for example; I'm not sure where on the world you are.)
    – Erica
    Oct 17, 2014 at 19:28
  • Do you know how to program? If yes, in which language? What's the current format of your data?
    – heltonbiker
    Oct 17, 2014 at 19:52
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    Erica - that is what I had hoped to do but unfortunately the X-axis of their generic grid is not in line with the equator its ~38.4 degrees counter clockwise off of flat. I forgot to mention that tidbit.
    – Seadub
    Oct 17, 2014 at 20:52
  • heltonbiker - unfortunatly no but i have access to folks that know VB, and C#.
    – Seadub
    Oct 17, 2014 at 20:57
  • Do you have access to ArcGIS? It has a "Local" projection that treats the earth as flat relative to the origin point. It also supports an azimuth parameter which might work for your rotation. Otherwise, georeference the data using your favorite GIS software.
    – mkennedy
    Oct 17, 2014 at 21:12

2 Answers 2

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An oblique mercator projection might solve your issue. See this Q&A for details:

Using customized Coordinate System in ArcGIS Desktop?

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I think what you need is to geo-reference your data. Here's a link: http://docs.qgis.org/2.2/en/docs/user_manual/plugins/plugins_georeferencer.html and I'm sure ARCgis has something similar...as does Python+gdal, and any legitimate GIS program.

The basic problem is that your coordinate system is totally non standard so doing a projection change will not get you anything. What you need to do is pick a projection and then assign proper coordinates to several of your grid points (control points). Depending on the algorithm, it could take 2, 3, or 4 points to properly do a transformation. If your grid is small, square and the measurement units are consistent then 2 points could get you a cheap transform. 3 or 4 points will help adjust any warping or curvature issues over larger distances or non-parallel grid lines.

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