[mapserver-users] Advice for MapServer project

[Milo van der Linden]

Timothy Mashford schreef:
> Thanks to everyone for their input.
>
> I have seen OpenLayers, I am not sure it is suitable as I really
> require a zoom-box tool (not shift-click), and also a separate layer
> control.
>   
The zoombox tool is available. Please check 
http://www.openlayers.org/dev/examples/controls.html, there is a zoombox 
button (just above the pan hand). Click it and start dragging.
> I have found GeoMoose to be fairly slow(?), and also full of features
> I don't require (e.g. slide zoom), although I guess these could be
> removed. The Morton County example is good.
>
> The reason I was thinking dbox.js was that it is fast & simple. But
> once I get up to that stage I will investigate all options.
>   
I don't know about GeoMoose, but in Openlayers you can retrieve all 
layers at once from a mapserver, or you can add layers through 
javascript. The second will speed up drawing the map because layers will 
be sequentially loaded. If your base layer is fast, users will get the 
idea the whole map is faster.

Another thing is that in OpenLayers you can use tiled and untiled for 
your WMS server. Tiled means your mapwindow (+ an extra invisible 
border) is split in 9 pieces. These pieces are loaded sequential. 
Untiled means that a single image is retrieved from mapserver. You can 
mix the both. Say that you load the big topograhic map tiled and your 
own smaller datasets untiled. It will give a nice speedy feel. The extra 
border has the effect that when you pan half a mapwindow to the side, 
the data is already loaded. Again, another way to give user-experience a 
feeling of speed.
> Can someone just help me understand how the postgresql database could
> be queried for data within a specific date range? I am thinking that
> the user could specify the dates in an initialisation page, and these
> dates could then be stored at hidden CGI variables (or javascript
> variables?). But if the data sources are specified in the mapfile, how
> do I pass the dates to postgresql?
>   
Date/Time functions for postgres are described here:
<http://developer.postgresql.org/pgdocs/postgres/functions-datetime.html>

DATA "the_geom FROM (
       SELECT this, that, other, the_geom
       FROM my_daterange_table_with_geometry
       WHERE mydateColumnValue < %someDatefromOpenlayers% and 
mydateColumnValue > %someDatefromOpenlayers% - integer '30'
     ) AS foo USING UNIQUE id USING SRID=4326"

(Example on how to get a time-frame of 30 days around a given date.)
> Sorry if my lack of knowledge is showing... Thanks again for the responses.
>
> Tim Mashford.
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