[mapserver-users] high memory usage on map draw

[Daniele Debernardi]

The solution is not pumping up the memory limit of the server, because 
if i get 2 request at the same time
I still have memory problem.

Which is the best way (output format) to generate high resolution map 
images with full symbology support?



Il 29.11.2011 15:49, Stephen Woodbridge ha scritto:
> On 11/29/2011 3:20 AM, Daniele Debernardi wrote:
>> Hi,
>> with mapserver trunk version (but i think with others too) I have to
>> generate very big map to be imported in a pdf file.
>> I use php mapscript to generate maps with 300 dpi for an A1/A0 pdf page
>> or bigger.
>> This mean that the map has dimensions like 15000x25000 pxl and when I
>> call the MapObj->draw method i get this error:
>>
>> PHP Warning: mapObj::draw(): [MapServer Error]: agg2CreateImage():
>> mapagg.cpp: 708: Out of memory allocating 1550851152 bytes.
>>
>> Map server is configured with the AGG/PNG driver with imagemode RGBA.
>>
>> Is it normal that need so much memory to generate the image?
>
> Just for the image buffer you need 15000x25000x4 pixels = 1500,000,000 
> and AGG might actually allocate a slight larger image buffer so it 
> does not create edge effects while antialiasing objects close to the 
> edges. So the above request does not seem unreasonable.
>
>> I already tryied the php ini_set memory_limit but with a limit of 2048M
>> i still have some problem with memory.
>
> Try setting the limit a little higher like to 2564-3072M can see if 
> your memory problems go away. Of course this assumes you have a system 
> with a lot of memory.
>
> -Steve W
>
>> I checked other possible outputs but generating maps in pdf through
>> Cairo driver but doc says that polygons filled with symbols are not
>> supported, and for that reason I cant use it.
>> SVG output has some limitations too like line drawn without symbols or
>> pixmap symbols not supported.
>>
>> Is there a better way to generate so big map images and imported in a
>> pdf file?
>>
>> Hope you guys can help me.
>>
>> Daniele
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>
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-- 
Cordiali saluti,
Ing. Debernardi Daniele

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