[mapserver-users] Multi layer/class : performance

[Alexandre Dube]

Stephen Kelly wrote:
> Alexandra,
>
> Hi, if you are really interested we have developed a tool here to create tiles for one of our mapping tools, and we generate about 100,000 very large mapserver maps per day and it would be easy for us to do some timing tests for you of both ways and to see which way is the fastest. 
>
>   

I use the TIGER 2008 data.  Do you use it in one of your maps ?

> One thing we have discovered is that what you do to your shape files is generally more important for speed, than what you do to your map files.
>
>   

Right.  Could you give me some examples of what you do ?  One thing I do 
is generalize my shapes and merge them together per state to have a 
faster map a lower scales.  Do you do the same for each of your scale 
level ?


We use KaMap to tile our map for each zoom level, so in the end we have 
a fast map but it sure takes some to cache the whole tiles.

> Although we do not rely on min/max scale and choose manually at what zoom what information is shown, and have that in separate map files, as that is the fastest (for what we need to do).
>
>   

I always edit my mapfiles manually, so having 11 instead of one seems 
like a lot of maintaining work, but I'm interested to hear more if 
you're willing...

> If you have any specific data / map files that you wanted me to test it on- I am sure that we could accommodate that.
>
>   

That's very kind of you, but I must decline the offer.  I can't share 
the actual mapfile, sorry.

> We can do 16,000 images one way, 16,000 the other way and time each image and see which way works.
>
> Thanks
>   

Thanks to you,

Alexandre

> Stephen Kelly 
> www.Peepel.com 
>
> -----Original Message-----
> From: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Alexandre Dube
> Sent: Friday, 12 June 2009 11:21 PM
> To: MAPSERVER USERS
> Subject: [mapserver-users] Multi layer/class : performance
>
> Hi,
>
>   I wonder which of theses two cases is better :
>
>   CASE 1 : Multi layer :
>   Define one layer per scale with minscale and maxscale, each having one 
> set of classes.
>
>   CASE 2 : One layer :
>   Define one layer only with one set of classes per scale.  The classes 
> would have the minscale and maxscale properties.
>
>   I find the second case "cleaner" but I'm wondering about performance.  
> Would it be slower to draw the bottom classes ( the ones with minscale 
> properties only, for example) ?
>
> Thanks,
>
>   


-- 
Alexandre Dubé
Mapgears
www.mapgears.com