5

I am trying to convert NAD 83 State Plane New York Long Island coordinates to Latitude/longitude. Below is my code - what am I doing wrong?

LatitudeLongitude[GeoPosition[{172248, 1002321, 0}, "SPCS83NY04"]]
Kuba
  • 136,707
  • 13
  • 279
  • 740
jackie
  • 53
  • 3

1 Answers1

8

This seems to work:

LatitudeLongitude @ GeoGridPosition[{172248, 1002321, 0}, "SPCS83NY04"]
(* {49.145, -75.732} *)
Michael E2
  • 235,386
  • 17
  • 334
  • 747
  • Good one. I delete my answer. +1 – halirutan Nov 25 '13 at 06:00
  • That does work! What's weird is I used ArcGIS to calculate Lat/Long from the same set of coordinates, and I got 40.639439, -73.9349 instead. Do you have any idea why that might be the case? – jackie Nov 25 '13 at 17:24
  • This is the projection info for the same datapoint in ArcGIS: Projected Coordinate System: NAD_1983_StatePlane_New_York_Long_Island_FIPS_3104_Feet Projection: Lambert_Conformal_Conic False_Easting: 984250.00000000 False_Northing: 0.00000000 Central_Meridian: -74.00000000 Standard_Parallel_1: 40.66666667 Standard_Parallel_2: 41.03333333 Latitude_Of_Origin: 40.16666667 Linear Unit: Foot_US

    Geographic Coordinate System: GCS_North_American_1983 Datum: D_North_American_1983 Prime Meridian: Greenwich Angular Unit: Degree

     – jackie Nov 25 '13 at 17:24
  • 1
    @jackie Could be the units, feet instead of meters? It's a big difference. – Michael E2 Nov 25 '13 at 19:07
  • Thanks Michael! That turned out to be the issue, and I got the same answer as the GIS application. Do you understand why GeoGridPosition has to be used insted of GeoPosition - is it because State Plane is a projected coordinate system rather than a geographic one? THANKS AGAIN! – jackie Nov 25 '13 at 21:33
  • @jackie No, I don't. I would guess that GeoPosition is for positions (anywhere on Earth) based on a datum, and GeoGridPosition is for positions based on cartographic grids, which perhaps apply to only a limited region -- I think that's what you're suggesting. My "expertise" with this problem is pretty much limited to being pretty good at finding things in the Mathematica documentation and knowing how Mathematica interfaces generally work. GIS is not my field. And you're welcome! :) – Michael E2 Nov 25 '13 at 22:12