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