[mapserver-users] Using Fast CGI with MapServer to alleviatepoor performance

Steve Lime Steve.Lime at dnr.state.mn.us
Fri Sep 19 12:21:57 EDT 2008


This shouldn't be the case, there are tests in the main API code to test
projections of the map
against layers to avoid this. I suspect it's projection related
though...

Steve

>>> On 9/19/2008 at 11:19 AM, in message
<48D3D0F9.5040904 at neogeo-online.net>,
Guillaume Sueur <guillaume.sueur at neogeo-online.net> wrote:
> I guess that wms makes a reprojection job as the request comes with
an
> EPSG code and the map projection is set by a proj string. Even if
they
> are equivalent, can MapServer know that and forget about reprojection
?
> 
> The cgi is rather straight forward as no EPSG is required. As the
layers
> don't have PROJECTION blocks, they are drawn straight forward.
> 
> my 2 cents.
> 
> Guillaume
> 
> Christopher Schmidt a écrit :
>> On Fri, Sep 19, 2008 at 03:34:42PM +0100, John Westwood wrote:
>>> Hi Everybody,
>>>
>>> I am attaching  a cut down version of my html, javascript and map
files. On 
> our server the EmbeddedMap.js lives in the OpenLayers directory and
is used 
> by gbhgis_openlayers.html.
>>>
>>> The test address http://148.197.8.119/gbhgis_openlayers.html . This
is just 
> a test server so please don't tell the whole World about it! :)
>>>
>>> There are four layers, 2 x raster (europe 1940s, WMS and MapServer)
and 2 x 
> vector / raster (Digital Chart of the World, WMS and MapServer) .
>> 
>> Okay, so to cut OpenLayers out of the loop:
>> 
>> 
>
http://148.197.8.119/cgi-bin/mapserv?map=/data/map-files/gbhgis.map&service=WMS&L

>
AYERS=europe&FORMAT=image%2Fpng&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=ap
>
plication%2Fvnd.ogc.se_inimage&SRS=epsg%3A3034&BBOX=2097152,2097152,4194304,419
> 4304&WIDTH=256&HEIGHT=256
>> 
>> 
>
http://148.197.8.119/cgi-bin/mapserv?map=/data/map-files/gbhgis.map&layers=europ

>
e&format=image%2Fpng&mode=map&map_imagetype=png&mapext=2097152+2097152+4194304+41
>
94304&imgext=2097152+2097152+4194304+4194304&map_size=256+256&imgx=128&imgy=128&im
> gxy=256+256
>> 
>> The former is WMS, the latter is not-WMS.
>> 
>> There is a very obvious speed difference between the two.
>> 
>> The reason the MapServer image has its colors wrong, for the record,
is
>> because it is using 8bit pngs instead of 24 bit pngs. My first
>> impression was that was the reason for the difference, but
>> unfortunately, 8bit gifs don't seem to fare any better.
>> 
>> Time for the URLs:
>> 
>> MapServer: real    0m0.660s
>> WMS: real   0m2.707s
>> 
>> These may help someone who knows MapServer investigate more.
>> 
>> Regards,
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