I have a document of my property in Puerto Rico made by an engineering
company that has 25 points, the angles and distances between the
points and an X and Y coordinates.  Example of the coordinates are
517.455 for X and 471.639 for Y.  What coordinate system are these and
how can I convert them to lat/long.  There is no other reference on
the drawing that would indicate where this is.  A picture of a USGS
chart with the area is on it but looks to be in error (which is why I
am pursuing this).  Can you help???

John McMahan

Hi Marinero,

don't know for certain, but this looks like the engineering company
have set up a local datum - this is quite common practice, especially
when working on a small build project whose boundary is clearly
defined. It is too much bother quoting the full lat / long reference
when a shortened form would do.

Two options that I can think of: Call up the engineering firm and
quote the drawing number to them to see if they can help, or, check to
see what is 517.445 meters (yards?) west and 471.639 meters (yards?)
south of the quoted co-ordinate - it maybe that this is an
intersection of a more commonly quoted coordinate system.

best of luck!

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