[ka-Map-users] tiling print service (WMS)
ed at topozone.com
Wed May 10 10:08:00 EDT 2006
Are you requesting the image data at native resolution (if your sources
are rasters), or is there resampling going on?
In normal production usage we limit users to 60 million pixels (6,000 x
10,000, for example) per image and easily produce those images
(sometimes more than one at a time) on a machine with 2GB of RAM.
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA 01863
ed at topozone.com
From: Bart van den Eijnden (OSGIS) [mailto:bartvde at xs4all.nl]
Sent: Wednesday, May 10, 2006 10:06 AM
To: Ed McNierney
Cc: ka-map-users at lists.maptools.org
Subject: RE: [ka-Map-users] tiling print service (WMS)
we did a quick test, 10k x 10k pixels did not finish on our machine with
1.5 Gb and 500 Mb swap. In the end Mapserver had 1700 Mb in memory, but
crashed with an itnernal server error when the swap was full.
How much RAM do you use in your servers for this kind of task? And what
kind of pixel width/height limit do you use?
Thanks in advance.
> Bart -
> RAM is cheap <g>. Seriously, although it depends a lot on the machine
> you're installing it in, that much memory (1GB) for many systems runs
> about USD $100. And depending on the usage level, you might just let
> the system swap and use virtual memory for the task.
> - Ed
> Ed McNierney
> President and Chief Mapmaker
> TopoZone.com / Maps a la carte, Inc.
> 73 Princeton Street, Suite 305
> North Chelmsford, MA 01863
> ed at topozone.com
> (978) 251-4242
> -----Original Message-----
> From: ka-map-users-bounces at lists.maptools.org
> [mailto:ka-map-users-bounces at lists.maptools.org] On Behalf Of Bart van
> den Eijnden (OSGIS)
> Sent: Wednesday, May 10, 2006 8:12 AM
> To: ka-map-users at lists.maptools.org
> Subject: RE: [ka-Map-users] tiling print service (WMS)
> Hi Ed,
> but won't that consume too much memory?
> For generating a 15.000 x 15.000 pixels PNG24 image Mapserver would
> take about 900 Mb into memory or not?
> Best regards,
>> Bart -
>> I'm not aware that a 2048x2048 pixel limit is "normal" for WMS
>> That's the default limit for MapServer but it is very easily changed.
>> I've done that for several years and produce very large images from
>> single MapServer WMS requests.
>> - Ed
>> Ed McNierney
>> President and Chief Mapmaker
>> TopoZone.com / Maps a la carte, Inc.
>> 73 Princeton Street, Suite 305
>> North Chelmsford, MA 01863
>> Phone: +1 (978) 251-4242
>> Fax: +1 (978) 251-1396
>> ed at topozone.com
>> -----Original Message-----
>> From: ka-map-users-bounces at lists.maptools.org
>> [mailto:ka-map-users-bounces at lists.maptools.org] On Behalf Of Bart
>> den Eijnden (OSGIS)
>> Sent: Wednesday, May 10, 2006 7:52 AM
>> To: ka-map-users at lists.maptools.org
>> Subject: [ka-Map-users] tiling print service (WMS)
>> Hi list,
>> can the ka-map tiling logic be used to create a WMS print service?
>> Imagine our use case, people wanting to print on A0 paper from
>> and ArcGIS has a WMS layer for aerial photographs in it. Ofcourse
>> normal WMS services limit themselves to 2048x2048 pixels like
> Mapserver does.
>> But ArcGIS requests an image of about 15000 pixels wide.
>> If a tiling php script could act as WMS service, and would ask for
>> 2048x2048 tiles to the aerial photograph WMS, and stream that back to
>> the client (ArcGIS), it could be a solution. Could ka-map be used for
>> Would it be a lot of work?
>> Also, is it possible to stream back the whole 15000x15000 pixels
>> without taking the whole thing in memory? I.e. could the script read
>> up the tiles from disk and stream them sequentially into 1 image?
>> Thanks in advance for some thoughts on this.
>> Best regards,
>> ka-Map-users mailing list
>> ka-Map-users at lists.maptools.org
> ka-Map-users mailing list
> ka-Map-users at lists.maptools.org
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