[Chameleon] Grid layer problem

[Tyler Mitchell]

Seb,
This is a very familiar problem for me as well.  It is a problem with 
how MapServer reprojects the GRID data points and how the GRID itself is 
created.  It is directly related to this bug: 
http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=411

The workaround I used was to create a grid file (not using built in 
MapServer GRID object) and make sure that it was dense, having points at 
every line intersection.

 From what I understand, the way the GRID features are created makes 
them have very few points making up the lines and when some of those 
points cannot be reprojected to fit on the map - then they got dropped. 
  Naturally, if one point in a two point line gets dropped - it's no 
longer a line and is not drawn.

I suggest you visit that bug report, register on the bugzilla, and add 
yourself to the "Add CC:" list in the top right corner of that bug 
screen (right under mine).  That way you'll be notified when fixes are made.

The good news is that Frank Warmerdam is looking at this problem over 
the next few weeks: http://ms.gis.umn.edu/development/rfc/ms-rfc-5.

Hope this helps, let me know if you need more explanation or need some 
more pointers on creating a grid file.

Tyler


Inizan, Sebastien (CDS-VPI) wrote:
> Dear chamelon people,
> 
> I have gone through a very strange problem: When I decide to display the
> grid 
> 
> LAYER
> 	  NAME "Grid"
> 	  DUMP FALSE
> 	  TRANSPARENCY 100
> 	  
> 	  TYPE LINE
> 	  
> 	  STATUS OFF
> 	  CLASS
> 		COLOR 150 205 118
> 		  LABEL
> 			TYPE BITMAP
> 			SIZE MEDIUM
> 			COLOR 255 128 89
> 		  END
> 	  END
> 	 
> 	  GRID
> 		  MINSUBDIVIDE 0
> 		  MAXSUBDIVIDE 10
> 		  MININTERVAL 0
> 		  MAXINTERVAL 10
> 		  LABELFORMAT ""
> 	 END
> END
> 
> The lines are not always drawn well, especially when zooming out in an
> orthographic projection.
> 
> Anyone has any idea why this problem occurs ?
> 
> Seb.
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>