Update, I replicated the correct projection by appending no_uoff: defined rot_conv: defined
to the PROJ_INFO file as per advice here http://osgeo-org.1803224.n2.nabble.com/GRASSLIST-8028-Oblique-Mercator-P rojection-in-GRASS-td1874326.html maybe my version (6.2.1 (2006)) of g.proj is old (6.2.1 (2006)) but it for sure didn't work as it should in this instance. Garret Dr. Garret Duffy ______________________ Department of Earth and Ocean Sciences National University of Ireland, Galway University Road Galway IRELAND Office: +353 (0)91 492169 Fax: +353 (0)91 750533 > _____________________________________________ > From: Duffy, Garret > Sent: 12-Oct-11 2:46 PM > To: '[email protected]' > Subject: RE: reprojection issue, using grass6.2 > > Hi, > > After doing some more investigating, it appears g.proj is not reading > all the parameters in : > > proj=omerc +ellps=WGS84 +k_0=1.0 +lat_0=53.25 +no_uoff +rot_conv > +alpha=-88 +lonc=-5.7 > > For example, the above command projects (-5.7d, 53.25d) correctly to > (X,Y)=(-5901478, 7901021). But after g.proj, the same point projects > to (X,Y)=(0,0). > > Can someone help with this? > > Thanks, > > Garret > > > Dr. Garret Duffy > ______________________ > Department of Earth and Ocean Sciences > > National University of Ireland, Galway > University Road > Galway > IRELAND > > Office: +353 (0)91 492169 > Fax: +353 (0)91 750533 > > > > _____________________________________________ > From: Duffy, Garret > Sent: 12-Oct-11 12:29 PM > To: '[email protected]' > Subject: reprojection issue, using grass6.2 > > Hi, > > I have three locations defined, one in Geographic 'projection', one > UTM and the other described below. When I try to reproject data, e.g. > a vector rectangle from either Geographic or UTM to the Oblique > Mercator projection defined below, the rectangle isn't rotated as I > expect. The origin of the projected coordinates looks to be in the > correct location but there is no rotation applied (geographic north is > supposed to ~45 deg from the y axis). BTW, is it even possible to > display a geodetic grid for a non-rectified projection? > > output from g.proj -p: > -PROJ_INFO------------------------------------------------- > name : Oblique Mercator > proj : omerc > a : 6378137 > es : 0.006694379990141316 > lat_0 : 53.25 > lonc : -5.7 > alpha : -88 > k : 1 > x_0 : 0 > y_0 : 0 > towgs84 : 0,0,0,0,0,0,0 > no_defs : defined > -PROJ_UNITS------------------------------------------------ > unit : meter > units : meters > meters : 1 > > > The command I used to specify the oblique projection is: > > proj +proj=omerc +ellps=WGS84 +k_0=1.0 +lat_0=53.25 +no_uoff +rot_conv > +alpha=-88 +lonc=-5.7 > > I must emphasize that I have checked the proj.4 parameters using the > command-line proj.4 and the *parameters are correct*. I applied these > parameters in GlobalMapper to get the final map to the state that I > would like eventually in GRASS. > > Any advice would be *greatly* appreciated, I have spent a lot of time > on this. > > Regards, > > Garret
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