AW: [Mapserver-users] Mapserver printing

[Arnulf Christl CCGIS]

Hi,
we have approached the problem in a little different way. Our WMS client has
to be able to query all sorts of severs and many have a farily low max limit
for the image size they will produce (MapServer is a positive exception to
that rule). Therfore the client breakes down the required large map into
several smaller tiles which the corresponding server is able to deliver. The
resulting tiles are then put back together in a simple HTML page. This is a
tedious process, if you want to be able to use several different services,
but maybe you can use this idea to reduce the size of individual images.
When we request very large tiled maps sometimes we also have noticed the
effect that one tile is blank (the file exists but has no content). As this
happens with different servers I guess that it has to do with PNG and not
with the server.

Regards, Arnulf.

-----Ursprüngliche Nachricht-----
Von: mapserver-users-admin at lists.gis.umn.edu
[mailto:mapserver-users-admin at lists.gis.umn.edu]Im Auftrag von Lowell
Filak
Gesendet: Dienstag, 27. Mai 2003 22:10
An: Zamil Murji; mapserver-users at lists.gis.umn.edu
Betreff: Re: [Mapserver-users] Mapserver printing


I'm not so sure that there is a limit.
I have found that PNG works extremely well for large images and I've never
had a problem with generating larger than 8.5x11 images w/ MapServer.
I just finished working with one that is 10218x8814 (~34x30) (no it wasn't
created with mapserver, but then that is why I am not sure there is a
limit).
Okay, I had to check it out... & MapServer reliably created a 6100x6100
(34x34 at 180dpi - which appears to be the max res. for that size that we can
pump through ZehRaster to our plotter) PNG file (the browser wouldn't render
it but Gimp opened it fine).
As far as the blank PNG in the browser is concerned:
What we have seen is that sometimes only part of the PNG is loaded, but that
only seems to happen on one of the apps we have that tracks vehicles and
loads a new map every 10-120 seconds.
We have not tracked down why it happens but it would seem that the html is
finished and loaded by the browser with the "img src" specified before the
image file is actually finished.
Lowell F.

The following message was sent by "Zamil Murji" <Zamil.Murji at divestco.com>
on Fri, 23 May 2003 11:16:03 -0600.

> Hi,
>
> We are currently trying to use mapserver to print images on an 8.5x11 inch
paper using the web. Up to date we have been very successfull. However, we
are now trying the next step - PLOTTING. I was wondering if anyone has any
idea how to approach this issue. I read in the past that mapserver has a
limit to the size of image that can be created, if so, how do I get around
this. Any suggestions would be welcome.
>
> Also, I noticed that when we started using png images all over our site.
Sometimes they would come back empty. NO error messages from mapserver, just
an empty image. If you refreshed the screen everything would start working
again. The image would be displayed again. Anybody observe similar output?
Once again, it happens randomly. Sometimes it works and sometimes it
doesn't.
>
> Zamil
>
> _______________________________________________
> Mapserver-users mailing list
> Mapserver-users at lists.gis.umn.edu
> http://lists.gis.umn.edu/mailman/listinfo/mapserver-users

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