[mapserver-users] high memory usage on map draw

[Stephen Woodbridge]

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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