Re: Large Igneous Provinces and Mercator projection

I can confirm the problem and will be working on a fix.  It affects both GMT 4 and 5.
-p

On Jan 9, 2014, at 4:25 AM, Langlois <[email protected]> wrote:

> Dear GMT-users,
> 
> I want to draw maps showing the large igneous provinces and hotspots of South Atlantic, using the LIPS.2011.gmt file available at ftp://ftp.ig.utexas.edu/pub/LIPS/Data/
> So I use -R-70/30/-55/25 and -JM-20/-15/12c but the map shows unexpected large colored bands (see attached map), which seems to be inadequately mapped LIPS from elsewhere…
> I note that :
> 1) the problem don’t appear when mapping the LIPS.2011.gmt file on a global map with Mollweide or Hammer projection
> 2) it disappears when I use projection from the zero longitude ! (that is, not with -JM0 or -JN0)
> 3) it disappears also when I write a new data file taking only the Atlantic's LIPS…
> So the problem comes clearly from the LIPS.2011 file (it was already there with the previous LIPS.2004 version…), but I don’t see where’s the bug in the data.
> 
> Thanks for help,
> Cyril Langlois
> 
> <GMT5_hotspots-Atl-S.jpg>
> Dr. Cyril LANGLOIS
> Professeur agrégé - enseignant de Sciences de la Terre 
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