map performance

Wed Dec 6 10:23:41 PST 2006

The data comes from a MySQL database.  The primary function of the  
site is to collect the data from users.  It is a PHP/MqSQL application.

The map is rendered each time for only a specific layer such as orthos.

So I go to the database(MySQL) and grab all distinct county ids that  
have a status of complete for that layer.

I build the regex string from that array of county ids and then use  
phpmapscript to set the expression for the county layer.

I understand the data structure you explained below.  But I don't  
understand how you would implement it.  Do you propose connecting to  
a data source directly from the mapfile?

At this point the only way I know how to color a county green on the  
map is by using a regular expression.  But I'm open to any method.   
Especially if its faster.

thanks,

boice

On Dec 6, 2006, at 12:39 PM, Steve Lime wrote:

> Ok, I looked back through another email and saw the output. I think  
> the
> bottleneck is in the large regular expressions. You'd be much  
> better off
> with a data structure like I outlined below. How do you determine, for
> example, which counties are do be drawn a certain way. That is, how do
> you build the regex? Using attributes in the shapefile? From another
> source?
>
> Steve
>
>>>> boice tomlin <boice at RUNSKIP.COM> 12/6/2006 10:55:52 AM >>>
>
> Hi Steve,
>
> Assuming I was using static class items.  Do you think my method of
> using a regular expression to specify which geographies to display  
> is a
> good method?
>
> Thanks for the tip on saving the map file.  Very cool.  It looks as I
> expected or at least hoped.  Basically my original map file with a few
> extra classes and regular expressions for the layers I display.
>
> Someone else suggested a method using postgis that would pull in shape
> data with less polygons for certain extents.
>
> Couldn't I use a version of the shape files I have now with less
> detail/polygons when rendering a map at larger extents?
>
> I actually want to explore every method I can for optimization.  My
> goal is a fairly descriptive national view in 1 tenth of a second.  Is
> that too lofty?
>
> thanks,
>
> boice
>
>
>
> On Dec 5, 2006, at 6:32 PM, Steve Lime wrote:
> Might be interesting to see what the resulting mapfile (after your
> dynamic work) looks like (use $map->save(...)).
>
>
> We'd really need to know more about the data, how you're doing
> classifications and such to comment more. There may be lots of ways
> to make things go faster. From the looks of it for each geography
> (city, county, tribe, state, nation) you have a bunch of variables
> that
> indicate
> if a data theme is available. One could organize that data like so
> (for
> example state level data):
>
>
> State  Hydrography  Watersheds ...
> MN     0                    1
> WI      3                    2
> IA       3                    0
> FL       1                    3
>
>
> Where 0 means no responce, 1 complete and so on. So in that case your
> class definitions would always be the same you'd
> be simply changing the variable you're mapping on (e.g. CLASSITEM),
> and
> you wouldn't need dynamic classes (or even MapScript for that
> matter).  Just thinking out loud...
>
>
> Steve
>
>
> boice tomlin <boice at RUNSKIP.COM> 12/4/2006 1:24:58 PM >>>
>
>
> Hello users,
>
>
> The map located here;
>
>
> http://gisinventory.net/status_maps.html
>
>
> takes a while to load.  At least at the national view where there is a
> lot of area to render.
>
>
> I am looking for alternative ways to generate the map that will
> significantly improve performance.
>
>
> Currently I am using php and looping through data and turning on
> layers
> as I go.  The PHP part is lightning fast.  But after I get the map
> ready
> mapserver takes several seconds to generate it.
>
>
> I'm curious about alternative ways to handle this problem and wonder
> if
> anyone had comments on any of them.
>
>
> 1) modifying the shape files in some way so the layer information is
> in
> those files so that all mapserver has to do is load those files and
> not
> depend on the map files.
> 2) using a db such as postgres with postgis so that layer information
> is available all in one compact source.
>
>
> Right now I have to generate a bunch of dynamic classes in PHP using
> the general method below.
>
>
> $lyr = $this->ramona_map->getLayerByName("state_yes");
>                 $cla = $lyr->getClass(0);
>                 $cla->setExpression("/".$expression."/");
>                 $lyr->set("status", MS_ON);
>
>
> I have to do this several hundred times to represent all of the data.
> The time it takes to generate the map seem proportionate to the amount
> of layers I make visible.  And again this is on the mapserver side and
> not PHP.  PHP does its part of the operation in thousandths of a
> second.
>
>
> anyone's thoughts are greatly appreciated.
>
>
> -boice tomlin
>
>
>
>
>
>
> ////////////////////////////
> Run Skip
> http://runskip.com/
>
>
>
>
> boice tomlin
>
>
>
>
> boice at runskip.com
>
>
>
>
> 503-528-6204
>
>
>
>
>
>
>
>
>
>
> ////////////////////////////
> Run Skip
> http://runskip.com/
>
>
> boice tomlin
>
>
> boice at runskip.com
>
>
> 503-528-6204
>
>
>

////////////////////////////
Run Skip
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boice tomlin

boice at runskip.com

503-528-6204

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