[Proj] Running the cities example in the pdf documents gives different results

[Jose Gonçalves]

The problem is with the longitude, which is 7 minutes west. If you do the
inverse projection with the projected coordinates, you get exactly 7
degrees east.

echo 485359.70 5730714.96 | proj -I +ellps=clrk66 +proj=poly
7dE     51d30'N

The symbol of minutes (') and the w are not being read correctly.

Regards

José




2016-05-10 15:45 GMT+01:00 Dean Schulze <dschulze at wirelessseismic.com>:

> Ahhh, so the default ellipsoid changed from the time of writing.
>
> Adding +ellps=clrk66 gives the same results as in the document for the
> first 3 cities, but the 4th city (London) is way off.  Here's my results:
>
>   $ proj +proj=poly +ellps=clrk66 -r cities.lat.lon.txt
>   # coordinates for a few cities
>   -4887590.49   7317961.48 Boston, United States
>   -5542524.55   6982689.05 New York, United States
>   171224.94     5415352.81 Paris, France
>   485359.70     5730714.96’w London, England
>
>
> The document shows the following for London:
>
> -8101.66 5707500.23 London, England
>
> so something else is wrong.  I'm using Rel. 4.8.0, 6 March 2012.
>
>
> ________________________________________
> From: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org]
> on behalf of Jose Gonçalves [jagoncal at gmail.com]
> Sent: Tuesday, May 10, 2016 2:19 AM
> To: PROJ.4 and general Projections Discussions
> Subject: Re: [Proj] Running the cities example in the pdf documents gives
> different results
>
> Hi
> You're not specifying an ellipsoid in the command line. Your PROJ version
> is using WGS84 by default.
> The default ellipsoid of the PROJ version used in the example of the PDF
> document was Clarke 66.
> You get those results with:
> proj +proj=poly +ellps=clrk66 -r
>
> Regards
>
> José Gonçalves
>
>
>
>
> 2016-05-09 23:41 GMT+01:00 Dean Schulze <dschulze at wirelessseismic.com
> <mailto:dschulze at wirelessseismic.com>>:
>
> I ran the cities example using the inputs on pg. 4 of the docs at
> ftp://ftp.remotesensing.org/proj/OF90-284.pdf, but I got different
> results than shown.  Here are the results I got:
>
> $ proj +proj=poly -r cities.lat.lon.txt
> # coordinates for a few cities
> -4887445.45     7318110.56 Boston, United States
> -5542376.59     6982834.25 New York, United States
> 171219.46       5415571.82 Paris, France
> 485343.33       5730932.66’w London, England
>
>
> The document linked above shows this:
>
> $ proj +proj=poly -r cities
> # coordinates for a few cities
> -4887590.49 7317961.48 Boston, United States
> -5542524.55 6982689.05 New York, United States
> 171224.94 5415352.81 Paris, France
> -8101.66 5707500.23 London, England
>
>
> Am I doing something wrong, or did something change from when the document
> was written?
>
> Thanks.
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