[R-sig-Geo] Proj4 - latitude or longitude exceeded limits

[Roger Bivand]

On Tue, 17 Jan 2017, aurelie.tschopp at vetsuisse.unibe.ch wrote:

> Dear all,
>
> I am analysing GPS Data from Chad. I need to first project the latitude 
> and longitudes. I use the package Proj4, the function project for this.
> I have 2 devices and with the data of the 1st device, the projection 
> worked perfectly. But with the data from the other device, I got this 
> error message: "Error in project(loc, "+proj=utm +zone=33 +ellps=WGS84 
> +datum=WGS84 +units=m +no_defs") : latitude or longitude exceeded 
> limits"
>
> I found that Chad was UTM 33P (Wikipedia UTM: 
> https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system 
> ), but some people could use the notification 33N: 33 for the zone and N 
> for the North hemisphere.
>
> My code is:
> loc <- dat[,c("Longitude","Latitude")
> loc_Zone33 <- project(loc, "+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 
> +units=m +no_defs")
>
> Does anybody know where my problem could be?

Well, the error message is coming from inside the proj.4 library: did you 
look at the input object? If one device was returning decimal geographical 
coordinates and the other a string with degrees, minutes and seconds in 
one "number":

library(rgdal)
project(matrix(c(19.0, 15.0), nrow=1), "+proj=utm +zone=33 +ellps=WGS84")
project(matrix(c(1900, 1500), nrow=1), "+proj=utm +zone=33 +ellps=WGS84")

In this setting I get:

> project(matrix(c(19.0, 15.0), nrow=1), "+proj=utm +zone=33 
+ellps=WGS84")
          [,1]    [,2]
[1,] 930334.7 1662218
> project(matrix(c(1900, 1500), nrow=1), "+proj=utm +zone=33 
+ellps=WGS84")
      [,1] [,2]
[1,]  Inf  Inf
Warning message:
In project(matrix(c(1900, 1500), nrow = 1), "+proj=utm +zone=33 
+ellps=WGS84") :
   1 projected point(s) not finite

but not your error. I suspect that the matrix you are passing contains 
non-geographical coordinates. If you are using the proj4 package (odd 
choice but there you are):

> library(proj4)
> project(matrix(c(19.0, 15.0), nrow=1), "+proj=utm +zone=33 
+ellps=WGS84")
          [,1]    [,2]
[1,] 930334.7 1662218
> project(matrix(c(1900, 1500), nrow=1), "+proj=utm +zone=33 
+ellps=WGS84")
Error in project(matrix(c(1900, 1500), nrow = 1), "+proj=utm +zone=33 
+ellps=WGS84") :
   latitude or longitude exceeded limits

confirming that it doesn't handle exceptions other than by a hard fail.

Roger


> Thank you
> Aurélie
>
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>

-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: Roger.Bivand at nhh.no
http://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
http://depsy.org/person/434412