3
$\begingroup$

I have a shapefile with the following "CoordinateSystemInformation":

"PROJCS" -> {"NAD_1983_StatePlane_Illinois_East_FIPS_1201_Feet",
"GEOGCS" -> {
  "GCS_North_American_1983", 
  "DATUM" -> {
    "North_American_Datum_1983",
    "SPHEROID" -> {"GRS_1980", 6.37814*10^6, 298.257}}, 
  "PRIMEM" -> {"Greenwich", 0.}, 
  "UNIT" -> {"Degree", 0.0174533}}, 
"PROJECTION" -> {"Transverse_Mercator"}, 
"PARAMETER" -> {"False_Easting", 984250.}, 
"PARAMETER" -> {"False_Northing", 0.}, 
"PARAMETER" -> {"Central_Meridian", -88.3333}, 
"PARAMETER" -> {"Scale_Factor", 0.999975}, 
"PARAMETER" -> {"Latitude_Of_Origin", 36.6667}, 
"UNIT" -> {"Foot_US", 0.304801}}

I would like to plot {Latitude, Longitude} points and overlay these images, but I am having trouble converting coordinates. The shapefile data contains coordinates in the vicinity of {1.16328*10^6, 1.89271*10^6}. (This is Chicago.)

One point I would like to plot is {41.8713, -87.6737}.

GeoGridPosition[GeoPosition[{41.8713, -87.6737}], "TransverseMercator"]

gives the wrong coordinates:

GeoGridPosition[{-0.164851, 0.743066}, "TransverseMercator"]

As does

GeoGridPosition[GeoPosition[{41.8713, -87.6737}], "Mercator"]

which yields:

GeoGridPosition[{1.6114, 0.806147}, "Mercator"]

What am I doing wrong? It's not a question of reversed coordinates as in this thread.

$\endgroup$
5
  • $\begingroup$ Could you please specify what would be the correct result in your example? $\endgroup$ Feb 19, 2014 at 4:11
  • $\begingroup$ @belisarius I'm not certain what the numbers should be but the coordinates should be quite close to {1.16328*10^6, 1.89271*10^6} $\endgroup$
    – mfvonh
    Feb 19, 2014 at 4:14
  • $\begingroup$ Try GeoPositionXYZ[GeoPosition[{41.8713, -87.6737}], "NAD83CORS96"] $\endgroup$ Feb 19, 2014 at 4:33
  • $\begingroup$ @belisarius That doesn't seem to do it. It gives me 3D coords (seeking 2d). And converting the 3D coords using GeoGridPosition does not yield answers in the right range. $\endgroup$
    – mfvonh
    Feb 19, 2014 at 4:52
  • $\begingroup$ Ok, it was just a try :(. Anyway, I fail to see what kind of 2D projection could give coordinates in that range (I don't know anything about Georeference!) $\endgroup$ Feb 19, 2014 at 5:02

1 Answer 1

7
$\begingroup$

The coordinates system of your shapefile is "NAD_1983_StatePlane_Illinois_East_FIPS_1201_Feet"

it is "SPCS83IL01" in GeoProjection Data

GeoGridPosition[GeoPosition[{41.8713, -87.6737}], "SPCS83IL01"]

This gives the coordinates in state plan system in meters, convert them into feet shall produce the right number you are looking for.

$\endgroup$
3
  • $\begingroup$ I modified the formatting of your answer so that the code is in a code block. I shouldn't have changed the actual code, but please check just to make sure. $\endgroup$ Feb 19, 2014 at 15:05
  • $\begingroup$ @Tuku Perfect, thanks! Meters should have been obvious but was throwing me off. $\endgroup$
    – mfvonh
    Feb 19, 2014 at 17:50
  • $\begingroup$ Wow! Finally, I found how to do this. This means Maryland 1800 I will have to write SPCS83MD00 $\endgroup$
    – user34018
    Nov 16, 2017 at 12:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.