[Mapserver-users] data/mapfile organization advice sought

[Ed McNierney]

Puneet -

As I've mentioned before on this list, I use the C preprocessor to
create master mapfile templates with macro expansions, #ifdef blocks,
etc.  It allows me to maintain one master set of template files, with a
make script to crank out all the mapfiles I need.

As for performance, I have at least one mapfile with 185 layers in it.
If you think about the amount of data being read / processed from your
spatial data files, reading a few more lines of text is really pretty
minor.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: (978) 251-4242  Fax: (978) 251-1396
ed at topozone.com


-----Original Message-----
From: Puneet Kishor [mailto:pkishor at geoanalytics.com] 
Sent: Tuesday, May 13, 2003 12:09 AM
To: Mapserver
Subject: [Mapserver-users] data/mapfile organization advice sought

To ms data mavens -- please give me a piece of your mind.

I have shapefile data of several countries, about 14 countries.

Each country has 8 to 12 different layers, but they are all called the 
same. For example, all countries have a layer called "layer1", 
"layer2", and so on, while a few countries may not have "layer8" or 
"layer11," etc.

If I were to draw all the countries together, they would draw 
correctly, that is, they are in the correct geographic space. However, 
their data are self-contained. That is, even though country1 and 
country2 are contiguous, drawing country1 does not bring up country2... 
they are in different folders.

How do I create and work with their mapfiles?

I can't really have one big mongo mapfile with all the layers of all 
the countries... it would be unworkable, and probably very inefficient.

On the other hand, if I have 14 different mapfiles, they will be almost 
identical to each other except for the path to the data. If I make a 
tweak in any one mapfile (for example, change the color or visible 
scale of a layer), I will have to go and change it in 14 different 
mapfiles.

Ideally I would like to have one master mapfile (like a template), and 
just substitute (on the fly) the path to the data. I guess I could do 
some preprocessing with Perl, and swap a filter keyword using regexp 
search, to create a working, valid mapfile on the fly, but I would also 
have to account for those one or two particular layers that happen to 
be absent for a given country.

Please share your insight.

Many tia.

Puneet.

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