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

[aurelie.tschopp at vetsuisse.unibe.ch]

Dear all

Thank you very much for your answers. 
In the meantime we found the error (it was really stupid): my latitude and longitudes were not numeric.
Since then everything is working fine with my projection and the my data analysis. Thank you. 
I will read your information on the proj4 bug also. Thank you for that. 

Cheers
Aurélie

-----Original Message-----
From: Roger Bivand [mailto:Roger.Bivand at nhh.no] 
Sent: mardi 17 janvier 2017 19:50
To: Tschopp, Aurélie (VETSUISSE)
Cc: r-sig-geo at r-project.org
Subject: Re: [R-sig-Geo] Proj4 - latitude or longitude exceeded limits

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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> R-sig-Geo at r-project.org
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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