I am not a GIS user, but I was given some shapefiles to work with. I do not have ArcGIS or any other GIS tool, but I do have Matlab with the mapping toolbox and R.
From what I can tell, the data is in eastings/northings in meters relative to some reference point. According to the metadata, the projection is WGS_1984_Mercator. There is another parameter that lists GCS_WGS_1984. I need to convert this into latitude and longitude relative to zero latitude and longitude. I do not need very high accuracy – within a degree or two is fine.
Here's some additional info, though I'm not totally sure that it's all relevant:
dbfdata: {[1] [7.5947e-05] [0.9000]}
dfbdate: [2012 7 2]
SPHEROID['WGS_1984',6378137.0,298.257223563]]
PROJECTION['Mercator'],
PARAMETER['False_Easting',0.0],
PARAMETER['False_Northing',0.0]
My apologies if I haven't provided enough information – please let me know what else I need to provide.
Best Answer
Your projection is likely to be the World Mercator projection. (EPSG 3395)
You can use the package proj4 in R to transform your coordinates. It is also supported by Matlab (as you can see here).
projection = +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs
inverse=true to go from cartographic coordinates to geographic coordinates (Lat/long)