[GRASS-dev] Re: [GRASS GIS] #608: GIS.m: Lat/Lon support broken in Map Display zooms

GRASS GIS trac at osgeo.org
Tue Sep 15 10:56:25 EDT 2009

#608: GIS.m: Lat/Lon support broken in Map Display zooms
  Reporter:  hamish   |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  closed                   
  Priority:  blocker  |   Milestone:  6.4.0                    
 Component:  Tcl      |     Version:  svn-develbranch6         
Resolution:  fixed    |    Keywords:  gis.m, LL                
  Platform:  All      |         Cpu:  All                      
Comment (by cmbarton):

 Good to know about the cc'ing. I don't know your OSGEO ID. Is there a
 place to find this easily?

 I wasn't very specific about what had changed in the zooming and will try
 to explain more here.

 When I started (at least on my system), any zoom out or panning raised a
 g.region error. Full window ('explore') mode was turned off for latlon
 locations because it raised an error when you tried to load the map. EW
 coordinates could be far beyond 180 degrees.

 Now, all coordinates seem correct. Full screen mode works as well as
 constrained mode (maybe a bit better). All zooming and panning works with
 the following 2 exceptions:

 1) If you keep trying to zoom out beyond 90N, 90S, 180E, 180W with
 constrained mode (and maybe in full screen mode if you do it some more),
 it will produce a viewing region that is too small and the error "maximum
 zoom in limit exceeded" is raised.

 2) If you zoom out beyond the max geographic coordinates more than once,
 the map view may not be what you were expecting (though I'm not sure what
 a user who keeps doing this IS expecting). That is, it may not be centered
 in the zoom out box, the displayed map may have an unexpected ht/width
 geometry, or it may even seem to zoom IN a little. This seems more
 pronounced in constrained mode than full-screen mode.

 I do have it set to just pan if the map is at or attempts to go beyond the
 max zoom out. However, we don't want this to take effect until the max
 zoom out. So the slightest bit below the max coordinates and it goes back
 to "normal" behavior. I could just have it return to the previous bounds
 too, but it would still have the same issue. I'm assuming that sometimes
 the user will want the map to show the entire world (i.e., max zoomout)
 and might like it centered on different longitudes (i.e., other than 0
 E/W) and have tried to preserve that possibility.

 What seems to happen is that if you try to zoom out beyond bounds once, it
 behaves well (i.e., goes into pan mode an shifts the center to be in the
 zoom out box or at the pointer for one-click zoom out). If you keep doing
 this, it begins to behave erratically and, with constrained mode,
 eventually reaches a max zoom in error.

 Hope that helps explain better where the functioning is at currently.


Ticket URL: <https://trac.osgeo.org/grass/ticket/608#comment:6>
GRASS GIS <http://grass.osgeo.org>

More information about the grass-dev mailing list