So close -- Lat / Long to Pennsylvania State Plane North NAD27

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

So close -- Lat / Long to Pennsylvania State Plane North NAD27

jdawg
This post has NOT been accepted by the mailing list yet.
This is my first time using Proj.4, and I'm struggling with converting Lat/Lon in decimal degrees to Pennsylvania State Plane North NAD27. I'm very unfamiliar with coordinate system terminology. Here's what I'm expecting based on what our mapping system tells me are the coordinates between the two systems:

-75.921819, 41.295735

should return

2502235.76228      416637.89162

when I convert it using cs2cs. (I'm expecting these values because when I use ArcMap to convert the coordinate system using the transformation called "NAD_1927_To_WGS_1984_79_CONUS", I get those values.) But what I'm getting from cs2cs is:

2502332.66      416669.38

This is the command line syntax I'm using, along with the output:

C:\proj\bin>cs2cs -v +proj=latlong +datum=NAD27 +ellps=clrk66 +nadgrids=conus,nt
v1_can.dat +to +init=epsg:32028
# ---- From Coordinate System ----
#Lat/long (Geodetic)
#
# +proj=latlong +datum=NAD27 +ellps=clrk66 +nadgrids=conus,ntv1_can.dat
#--- following specified but NOT used
# +ellps=clrk66 +nadgrids=conus,ntv1_can.dat
# ---- To Coordinate System ----
#Lambert Conformal Conic
#       Conic, Sph&Ell
#       lat_1= and lat_2= or lat_0
# +init=epsg:32028 +proj=lcc +lat_1=40.88333333333333 +lat_2=41.95
# +lat_0=40.16666666666666 +lon_0=-77.75 +x_0=609601.2192024384 +y_0=0
# +ellps=clrk66 +datum=NAD27 +to_meter=0.3048006096012192 +no_defs
# +nadgrids=conus,ntv1_can.dat
#--- following specified but NOT used
# +ellps=clrk66
-75.921819 41.295735
2502332.66      416669.38 0.000


The values are so close, but not close enough, and I can't figure out where the discrepancy is! Can any of you gurus advise me in this matter?? Thanks very much!!

Jeremy
Reply | Threaded
Open this post in threaded view
|

Re: So close -- Lat / Long to Pennsylvania State Plane North NAD27

jdawg
This post has NOT been accepted by the mailing list yet.
sorry...bumping this message to get it on the mailing list... :)