non-square shapefiles and tileindex

[Brent Fraser]

Ara,

  Mapserver uses only the min & max x,y of the shape in the
shapefile to determine if it should open the tile (raster of
vector) the shape points to, regardless of how complex the
shape is.  If the tile's rectangular extents intersect the
output graphic's extents, it opens the tile and reads all
the data in it.  It then attempts to render all the data
from the tile into the output graphic file.

    It does not use the index shape to do any polygon
clipping (if that's your reason for writing the complex
polys).

  If your goal is to not write any "null" pixels (e.g.
black)  from an input image into the output image, you can
use the OFFSITE layer setting in the R,G,B values that are
to be considered "null" and should not be rendered into the
output image.  And there may be some more sophisticated
techniques using the PROCESSING object in the layer
definition.

Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta

----- Original Message ----- 
From: "Ara T Howard" <ara.t.howard at NOAA.GOV>
To: <MAPSERVER-USERS at LISTS.UMN.EDU>
Sent: Friday, February 02, 2007 3:59 PM
Subject: [UMN_MAPSERVER-USERS] non-square shapefiles and
tileindex


> i'm about to write code to dump out non-square shape files
containing complex
> shapes in them.
>
> is there any reason i shouldn't expect this to work with
the TILEINDEX layer
> option?
>
> sorry if i missed this in the docs - my searching hasn't
turned up anything
> yet...
>
> regards.
>
> -a
> -- 
> we can deny everything, except that we have the
possibility of being better.
> simply reflect on that.
> - the dalai lama