[mapserver-users] Difference in GD vs AGG PNG output -- seams in my shape files.

[Lime, Steve D (DNR)]

You may be seeing some deficiencies in the analytical AA algorithm AGG uses. I remember reading about it awhile back in discussions about  alternative algorithms and recall it being prominent with vertical edges. Have you tried setting an outline color to the same value as your fill color? That may help.

Steve
________________________________________
From: mapserver-users-bounces at lists.osgeo.org [mapserver-users-bounces at lists.osgeo.org] On Behalf Of Mark Deneen [mdeneen at gmail.com]
Sent: Monday, May 03, 2010 2:42 PM
To: mapserver-users at lists.osgeo.org
Subject: [mapserver-users] Difference in GD vs AGG PNG output -- seams in my    shape files.

Hi,

I recently upgraded from 5.2.x to 5.6.1, and from GD to AGG.

Here is my output:

AGG: http://i44.tinypic.com/5oh261.png

GD: http://i39.tinypic.com/2h4j409.png

Visual Representation of the shapefile: http://i44.tinypic.com/1zz2u76.png

Look north of Cancun -- the AGG driver is showing seams where the polygons connect in my shape file.  It doesn't do it for all of them, but I see it a lot, especially when the seams are not straight N/S or E/W.  I feel that it has something to do with AGG's antialiasing, but I've not been able to pin it down.

Is there any way to resolve this?  I'd really like to use the AGG driver, I love the output it produces, minus the white lines!

Mark