State of MapServer...

[Stephen Lime]

I'm very fond of the test suite. I actually created it with the notion of IT becoming
the primary demo. Big demos are fine for ideas but often they get too complex
to see what's really happening. For example, here's a nifty application:

  http://maps.dnr.state.mn.us:8080/landview/ 

Lot's of intersting stuff but not exactly where you want to start. So, I'd like to
see the test_suite serve as a basis for a demo suite.

Steve

On the scale thing. Here's the equation:

  map_distance = (map_width-1)/(MS_PPI*inches_per_unit);
  ground_distance = extent_maxx - extent_minx;
  scale = ground_distance/map_distance;

where 

  MS_PPI = number of pixels per inch for a computer monitor = 72;
  inches_per_unit = number of inches per map unit (i.e. UNITS ...)

Other values are what you'd expect. Since MapServer computes things so that cellsize is
square you can use either dimension, x or y, to calculate scale.

Stephen Lime
Internet Applications Analyst

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> John Hockaday <johnh at erin.gov.au> 10/25/00 05:41PM >>>
Hi,

I am very pleased with this list.  I have noticed that there are many
people who seem to understand how the system works and respond to the
questions.  I, on the other hand, am one who usually asks the
questions, or if I know the answer someone else has beaten me to send
the answer to the list.

When I was setting up my mapserv I found the mapserv test suite (
http://arachnid.dnr.state.mn.us/ms_test/index.html ) to be very
useful.  I used the simple example templates, map files and query
template files to work out more complicated files of my own.  I was so
impressed with this method I am going to adopt it for my own
application/maintenance online documentation and link to the relevant
parts of the mapserv documentation.  May I suggest that other sites do
this and the mapserv documentation link to these sites?  For example,
It would be great if there was a link to an applet example, mapscript
example Java servlet example (if there is one) etc.  Someone must have
tested these parts of the system as indicated by those knowledgeable
people on the list and maybe these test sites could be used as
examples.  Although documentation is essential I personally find
examples a must to help me through development.

It also seems that there are questions that are very similar and it
would appear that the documentation may be lacking in this area.  If
the talented people, whom I presume will volunteer for the
documentation task as they know what it all means, could note this and
update the relevant areas as it happens on the list.  I know that
documentation is hard to keep up with and I just thought that this
might be a good start.

Other areas of improvement would be in the details.  Each item seems to
be covered in the documentation but a little more explanation would be
nice.  For instance, "MAXSCALE", "MINSCALE" etc. mention the maximum
and minimum scale at which the layers are switched off and on, but how
is the scale calculated?  I thought it would be pixels/mapunits or visa
versa but this didn't seem to compute.  I did work around the problem
by fiddling with numbers until the layers switched on and off at what
seemed appropriate to me.

I know this doesn't answer Steve's question, but I thought that I would
just send in my "two bobs" worth.  (I think that that is "two quarters"
or "two cents" worth in the USA.) ;-)



Johnh