need mapserv.exe recompiled with max layers=500

[Ravi]

Jacob,

I did a few quick experiments. This seems to solve the problem. I think 
now I can cut down layers to 1/10th of original layers. This solution 
can also help me optimize some other things as well.

You were very helpful. Thanks a lot. Let me know if I can do something 
for you.

Regards
Ravi



Delfos, Jacob wrote:
> Ravi,
> 
> Do you actually have the information that you classify it with? I mean, 
> do you know the population of each county?
> 
> Adding a new attribute is very straightforward. If you have GIS software 
> (e.g. ArcGIS), it should be able to do that (What software do you 
> have?). If you haven't got GIS software, I have found "OpenOffice Calc" 
> to be the most reliable DBF editor (the .dbf file holds the attributes 
> of a shapefile). OpenOffice (free software) does have a tendency to add 
> redundant decimal places. You can open it up, add a field, and fill in 
> the values. Do NOT change the order of the rows, because then the wrong 
> attribute is linked to a county. Always make a backup of your DBF first.
> You can also use Excel to open your DBF (not free). It does not add 
> redundant decimal places, but it is unpredictable at times with text 
> columns, which can get truncated or left out altogether, though number 
> columns are usually dealt with properly.
> 
> regards,
> 
> Jacob
> 
> 
> 
> 
> -----Original Message-----
> From: Ravi [mailto:ravikapoor101 at gmail.com]
> Sent: Wed 12/6/2006 3:29 PM
> To: Delfos, Jacob
> Cc: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] need mapserv.exe recompiled with max 
> layers=500
> 
> 
> Yes it makes sense. However...here is the catch.
> 
> I do not know how to add 'population' attribute to be able to do the
> comparison you mentioned. I also tried to get PostGIS working, I get no
> errors, I have checked all configuration but no maps show up.
> 
> So can you throw some light on how to add 'population' of each county
> inside each shapefile so that I can do the comparison you mentioned? In
> absence of that either I select each county individually (slow) or do
> what I am doing now which is create files as follows and create one
> layer for each file:
> 
> PopulationCountyColor1.shp
> PopulationCountyColor2.shp
> ...
> ...
> PopulationCountyColor10.shp
> PopulationZipCodeColor1.shp
> ..
> ...
> GrowthZipCodeColor10.shp
> 
> These come out to be a total of 240 files (8x3x10, 8 parameters, 3
> shapes and 10 colors).
> 
> Regards
> Ravi
> 
> 
> Delfos, Jacob wrote:
>  > Yes, but I figured there had to be a reason why you are selecting each
>  > county individually, resulting in slow performance if you combine ten
>  > classes into a layer. If you have only got 300 objects that require
>  > classifying, then having ten classes should really not be a drama. Of
>  > course if you classify each object individually, then it becomes
>  > expensive (300 comparisons with 300 objects times 10 = 900,000
>  > comparisons: SLOW). But if you use ranges (e.g. ('[population]'>100) AND
>  > ('[population]'<200)   ) then you reduce it to 600 comparisons per
>  > class, meaning 6000 comparisons for a layer. That's way less than 
> 900,000.
>  >
>  > Does this make sense in your scenario?
>  >
>  >
>  > -----Original Message-----
>  > From: Ravi [mailto:ravikapoor101 at gmail.com]
>  > Sent: Wed 12/6/2006 3:13 PM
>  > To: Delfos, Jacob
>  > Cc: MAPSERVER-USERS at LISTS.UMN.EDU
>  > Subject: Re: [UMN_MAPSERVER-USERS] need mapserv.exe recompiled with max
>  > layers= 500
>  >
>  >
>  > Hi Jacob,
>  >
>  > I am doing pre-generation of layers. I thought each layer has to be a
>  > separate shape file and need a separate "LAYER" tag. Is that not so?
>  >
>  > Thanks for your thoughts
>  > Ravi
>  >
>  >
>  > Delfos, Jacob wrote:
>  >  > Ravi,
>  >  >
>  >  > Why do you select out each county individually, rather than having an
>  > expression that defines a range of population density? For example,
>  > EXPRESSION ('[populationdensity]'>500)
>  >  >
>  >  > If you can't do that, do you have the ability to pre-generate the
>  > classified layers, such that each layer requires no further
>  > classification, and contains a class (1 through to 10) of which colour
>  > it should have?
>  >  >
>  >  > If even that fails, you could consider rendering your areas to a
>  > raster, and only start showing individual vector-based objects when a
>  > user zooms in. I have used that approach to 'fake' the displaying of
>  > 100,000s of polygons, so that they wouldn't have to be generated at
>  > runtime. You  can use minscale and maxscale to turn the raster off when
>  > the vector comes in.
>  >  >
>  >  > Otherwise, can you tell us what datasource you are using? Shapefiles?
>  > PostGIS?
>  >  >
>  >  > regards,
>  >  >
>  >  > Jacob
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  > -----Original Message-----
>  >  > From: UMN MapServer Users List on behalf of Ravi
>  >  > Sent: Wed 12/6/2006 2:41 PM
>  >  > To: MAPSERVER-USERS at LISTS.UMN.EDU
>  >  > Subject: [UMN_MAPSERVER-USERS] need mapserv.exe recompiled with max
>  > layers = 500
>  >  >
>  >  > Hi,
>  >  >
>  >  > Can somebody recompile the mapserv.exe with max layers = 500? Or guide
>  >  > me how to do this? If you want to charge for this kind of service, can
>  >  > you send me an email telling me how much would you charge?
>  >  >
>  >  > Yes I have thought about reducing the layers and tried various options
>  >  > to the best of my knowledge but so far I have not come up with a
>  > solution.
>  >  >
>  >  > If you are curious why I need so many layers or can help me reduce
>  >  > layers here is what I am doing. This is very confusing...sorry I am
>  >  > trying my best to explain.
>  >  >
>  >  > I want to show population density in US using 10 different colors. 
> Hence
>  >  > I need 10 layers (1 for each color). I am not able to use single layer
>  >  > as I would need to define 10 classes with different colors. Each class
>  >  > will select 300 counties using "EXPRESSION" as follows:
>  >  > EXPRESSION ('[FIPSSTCO]'='21037' or '[FIPSSTCO]'='21125' or.....
>  >  > Selecting 300 counties like this is VERY slow.
>  >  >
>  >  > Now we can see entire US map with colors. When the user zooms in, 
> I have
>  >  > to show same thing using zip codes. Further zooming in shows the data
>  >  > divided by block groups. Hence total layers = 10x3 = 30.
>  >  >
>  >  > Now I need to show 8 such parameters (potentially 16). Hence I need
>  >  > 10x3x16 = 480 layers
>  >  >
>  >  > Thanks for help
>  >  > Ravi
>  >  >
>  >
>  >
> 
>