[Mapserver-users] A few Mapserv questions

[James Mclean]

Hi All,

I have worked through the Tutorial on getting mapserver 4.0 to work, but 
after the first tutorial I have some questions...

Please bear in mind that I am new to this GIS type stuff, its like 
learning french to me. Im a programmer, not a GIS guy :)

I have created a basic .map as outlined in the tutorial, and after 
working through some problems because of a missing PROJ library, I have 
a working mapserv binary.

The basic map file I am using (test.map) is as below... A direct copy 
and paste from the tuit, with the nesicerry changes.

MAP
   IMAGETYPE PNG
   EXTENT 254184.15504499 6174213.6411365 314868.3598851 6210501.3473782
   SIZE 400 300
   SHAPEPATH "/home/jamesmc/asm2.air-stream.org/maps/i5409/"
   IMAGECOLOR 255 255 255

   PROJECTION
     "proj=laea"
     "ellps=clrk66"
     "lat_0=45"
     "lon_0=-100"
   #
   # Alternatively, you can specify an EPSG code.
   # "init=epsg:2163"
   #
   END

   # Start of LAYER DEFINITIONS 
---------------------------------------------
   LAYER # States polygon layer begins here
     NAME states
     DATA i5409t_r
     STATUS DEFAULT
     TYPE POLYGON

     PROJECTION
       "init=epsg:4269"
     END

     CLASS
       COLOR 232 232 232
       OUTLINECOLOR 32 32 32
     END
   END # States polygon layer ends here
   # End of LAYER DEFINITIONS -------------------------------
END # end of map file/object

First question is, the EXTENT paramerter in the map file. What exactly 
are the numbers ment to be? The tuit says 'Meters', so I assume that 
means Easting, Northing, but what are the last two? How can I tell what 
format my maps use?

Second question is, I have my SHAPEPATH set correctly (I presume), the 
directory has 242 files with the extensions .dbf, .prj, .shp, .shx. I 
assume these are the ERSI Shapefiles I need to reference?

The data I downloaded was 1:250K Australian maps, in the MapInfo 
Shapefile format.

In the LAYER section, I have 'DATA i5409t_r', but i5409t_r is just one 
file. What if the data I want is not in that particular file? How do I 
know what is in each file? I tried ogrinfo, but I dont understand half 
of whats going on with it... ogrinfo says 'i5409t_r' is a Polygon file, 
as what TYPE says in test.map.

Based on the above map file, nothing is generated but a plain, white 
image. Changing the IMAGECOLOR does change the color of the image, so 
its not a web caching issue.

I would like to browse the ERSI Shapefiles to see the maps in them, 
whats a good program I can use on Linux to do so? I do not have access 
to a Microsoft based system. Is there a generic .map file I can use with 
Mapserver to browse my ERSI Shapefiles? Dont say GRASS, im not a GIS 
professional, I cant understand that program...

How can I view the 'layers' in my shapefiles?

I am using Debian 3.1 unstable, on kernel 2.4.22 on x86. Mapserver 
version is 4.0.1, GCC 3.3.3, Mapserver configure command = ./configure 
--with-ogr=/home/jamesmc/src/gdal-1.1.9 --with-gdal --with-proj 
--with-jpeg --with-gd --with-httpd=/usr/sbin/apache

Apache version is 1.3.29
PHP/Mapscript not built, using mapserv cgi binary.

No errors encountered in the browser, or in HTTPD logs.

URL 
http://127.0.0.1/cgi-bin/mapserv?map=/home/jamesmc/asm2.air-stream.org/maps/maps/test.map&mode=map

I hope someone is able to shed light on these questions, I would rather 
do it myself with Mapserver than use mapblast, which cant generate an 
Australian map to save its life...

Regards

James Mclean