[Mapserver-users] time support

[Dean Gadoury]

Tom,
Here is a simple case in which we could request data by time. We add a 
time parameter on the WMS URL, for example:
http://server/cgi-bin/servicename?version=1.1.0&request=getmap&time=2003-12-01%2012:00:00
 
In the map file on the server we would have an expression in a FILTER in 
a layer, but this could also work with an expression in a class. For 
example for a shapefile we could have something like:

  FILTERITEM "TIME"  # where time is the name of the time column in the 
shapefile's dbf
  FILTER "%time%"       # this substitutes the value that is given on 
the query string, in this case 2003-12-01 12:00:00  (the %20 in the URL 
is a space)
 
I used the simplest case for my expression, but any valid expression 
should work. The result would be that only records matching the time 
passed on the URL would be shown.

Using this method the time format doesn't really matter. In this example 
its yyyy-mm-dd hh:mm:ss. Real time support in WMS should use the time 
format specified in the WMS spec: ISO 8601 "extended" format. It would 
probably be a good idea to start using that now so that when real time 
support is built into MapServer you won't need to change it.

I hope that helps
Dean



Kralidis,Tom [Burlington] wrote:

>>-----Original Message-----
>>From: Dean Gadoury [mailto:gadoury at dmsolutions.ca] 
>>Sent: Tuesday, December 16, 2003 1:22 PM
>>To: Kralidis,Tom [Burlington]
>>Cc: mapserver-users at lists.gis.umn.edu
>>Subject: Re: [Mapserver-users] time support
>>
>>
>>Here's a quick response, and others can fill in details that I miss.
>>
>>MapServer does not currently support the time parameter in its WMS 
>>interface, but it is in the plans for a future release. 
>>Someone else can 
>>give more detail on that.
>>
>>    
>>
>
>This would be appreciated, as this is a valued feature. 
>
>  
>
>>We have come up with a work around for a project we are currently 
>>working on though. We use the variable substitution function in 
>>MapServer 4.0. We add 'time=value' to the URL of our WMS 
>>request, and in 
>>the mapfile on the server side we use the variable %time% in 
>>a layer's 
>>FILTER object. This method does not allow us to select a 
>>range of times, 
>>but perhaps you can do the same thing with two variables like 
>>'starttime' and 'endtime' or something similar.
>>
>>    
>>
>
>Do you have an exmaple snippet of how this works?  Basically, time values
>would be in an attribute field in our data.  Also, how should time values be
>formatted?
>
>..Tom
>
>
>  
>
>>Dean
>>
>>
>>Kralidis,Tom [Burlington] wrote:
>>
>>    
>>
>>>Hi,
>>>
>>>We have an activity which requires interfacing with a WMS 
>>>      
>>>
>>supporting the
>>    
>>
>>>TIME construct, as per ISO8601, for OGC:WMS communication 
>>>      
>>>
>>with point-based
>>    
>>
>>>temporal observation data.
>>>
>>>Does MapServer support this in its WMS face?  If no, are 
>>>      
>>>
>>there any plans to
>>    
>>
>>>do so, and ETA?  Are there any workaround / interim 
>>>      
>>>
>>solutions to do this?
>>    
>>
>>>Basically looking for a state of affairs w.r.t. this issue.
>>>
>>>Thanks
>>>
>>>..Tom
>>>=========================
>>>Tom Kralidis
>>>Systems Scientist
>>>Environment Canada
>>>Tel: +01-905-336-4409
>>>http://www.ec.gc.ca/cise/
>>>========================= 
>>>_______________________________________________
>>>Mapserver-users mailing list
>>>Mapserver-users at lists.gis.umn.edu
>>>http://lists.gis.umn.edu/mailman/listinfo/mapserver-users
>>>
>>> 
>>>
>>>      
>>>
>>-- 
>>___________________________
>>
>>Dean Gadoury
>>
>>DM Solutions Group
>>72 Chamberlain Ave. Third Floor
>>Ottawa, Ontario. K1S 1V9
>>613 565-5056 ext. 24
>>
>>gadoury at dmsolutions.ca
>>www.dmsolutions.ca
>>
>>
>>
>>    
>>
>
>  
>

-- 
___________________________

Dean Gadoury

DM Solutions Group
72 Chamberlain Ave. Third Floor
Ottawa, Ontario. K1S 1V9
613 565-5056 ext. 24

gadoury at dmsolutions.ca
www.dmsolutions.ca