[Mapbender-users] how much time for pdf creation ???

Michael Schulz mschulz at webgis.de
Tue Oct 7 03:40:21 EDT 2008


Hi Marc,

true, my timing estimations are not based on longer term time
measurements, but on testing and experiences.

Actually, why the way to weld the maps together was choosen, I cannot
comment. Putting timing figures to the various parts of the creation
process might be interesting, we should think about a testing
procedure. At the practical level, I suspect it won't help much
because you won't get one setup like the other, depending on server
power, network bandwidth, fcgi vs. cgi vs. apache-module, print
quality, etc.

About whether the memory_limit has influence on the speed, maybe
someone with more insight has to comment. The only time impact i can
imagine, would stem from swapping, but from what I have observed, the
pdf generation will simply die when too much memory is consumed.

One interesting feature that we'd need to think of implementing is the
pdf generation with tiled maps. The are a lot of special problems with
tiling, but overall it would enable real A2 - A0 printing without
running into wms pixel size limits. OTOH, this would really increase
time consumption, because at the moment we request one map after the
other and this has to be multiplied with the tiling and the fact, that
e.g. mapserver creates one big map faster than several small tiles.

Cheers, Michael


2008/10/7 Marc Jansen <jansen.marc at gmx.de>:
> Hi List, Hi Michael,
>
> have the single parts of the creation of a pdf file been timed or is
> your answer based on your gut feeling?
>
> I could imagine that the merging of files might take long as well. This
> should also be the part that is affected by your changes in php.ini.
> Maybe we should try to actually put figures (in terms of seconds and
> memory consumption) behind the current implementation.
>
> Why exactly do we merge / weld the files prior to adding them to the
> PDF? Does this still make sense? And maybe we should consider splitting
> up one big image request into many smaller ones (at least for background
> wms without labeling) this might work out well.
>
> Bye and regards,
> Marc
>
>
> Michael Schulz schrieb:
>> Hi,
>>
>> "usually" depends at most on the desired quality of the print, meaning
>> either 72 or 288 dpi ...
>> The slowest part of the pdf generation are the getmap requests and
>> waiting for the response images. A reasonible WMS should be able to
>> produce a 72 dpi A4 image in several seconds, so depending on how many
>> wms are included in the pdf, a total time of one minute seems pretty
>> long (but not necessarily impossible).
>>
>> If you have problems with not finished pdf generation (white page
>> after starting the print) I'd recommend an increased memory_limit
>> value (e.g 64M) in your php.ini.
>>
>> HTH, Michael
>>
>>
>> 2008/10/6 vollbotz <volker.emmel at lwk-rlp.de>:
>>
>>> hi,
>>>
>>> i just want to know how long mapbender "usually" needs for the production of
>>> a pdf.
>>>
>>> i use mapbender_2.5 and the ubuntu_vm from http://www.gisvm.com/
>>>
>>>
>>>> i use the apache compression but have done no changes on the ubuntu
>>>> system...
>>>>
>>> only on php.ini:
>>> max_execution_time = 60     ; Maximum execution time of each script, in
>>> seconds
>>> max_input_time = 120 ; Maximum amount of time each script may spend parsing
>>> request data
>>> ;max_input_nesting_level = 64 ; Maximum input variable nesting level
>>> memory_limit = 16M      ; Maximum amount of memory a script may consume
>>> (16MB)
>>>
>>>
>>> right now - i need for a din a4 page about one minute...
>>> is this usually ??
>>>
>>> what can i do ??
>>>
>>> thanks
>>> --
>>> View this message in context: http://www.nabble.com/how-much-time-for-pdf-creation-----tp19837702p19837702.html
>>> Sent from the mapbender-users mailing list archive at Nabble.com.
>>>
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>>>
>>
>>
>>
>>
>
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