WMS time question

Bart van den Eijnden (OSGIS) bartvde at XS4ALL.NL
Thu Jul 27 12:39:52 EDT 2006


Sounds like the correct approach.

Best regards,
Bart

Yewondwossen Assefa wrote:

> Hi There,
>
>  We could add a support by supporting "wms_timeitem_min" and 
> "wms_timeitem_max" (mutually exclusive with wms_timeitem) and doing 
> the following for different time values passed in the wms TIME 
> parameter :
>
>   - single time for example: ...&TIME=2004-10-12&... would give 
> (`[time_field_min]` <= `2004-10-12`) and  `[time_field_max]` >= 
> `2004-10-12`)
>
>   - multiple values (2004-10-12, 2004-10-13) would give 
> ((`[time_field_min]` <= `2004-10-12` and  `[time_field_max]` >= 
> `2004-10-12`) OR (`[time_field_min]` <= `2004-10-13`) and 
> `[time_field_max]` >= `2004-10-13`))
>
>   - single range : 2004-10-12/2004-10-13 transforms to 
> ((`[time_field_min]` <= `2004-10-12`) AND (`[time_field_max]` >= 
> `2004-10-13`))
>
>   - multiple ranges (2004-10-12/2004-10-13, 2004-10-15/2004-10-16) 
> transform to ((`[time_field_min]` <= `2004-10-12`) AND 
> (`[time_field_max]` >= `2004-10-13`)) OR ((`[time_field_min]` <= 
> `2004-10-15`) AND (`[time_field_max]` >= `2004-10-16`))
>
>  Is this acceptable ? Do you see other ways ? I have added a bug 
> related to this http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1849
>
>
> Later,
>
>
> Eijnden, Bart van den (AGI) wrote:
>
>> Hi Assefa,
>>
>> so e.g. you would have (DD-MM-YYYY):
>>
>> ROAD_SEGMENT_ID        MIN_DATE        MAX_DATE
>> 1                01-01-2006        01-04-2006
>> 2                01-03-2006        01-06-2006
>> etc.
>>
>> So these represent validity, the road segment is valid/existant 
>> between MIN_DATE and MAX_DATE.
>>
>> So if I want a map with the situation of 01-05-2006, 1 would not be 
>> on it, but 2 would be.
>>
>> If I would want a map with the situation of 15-03-2006 until 
>> 15-04-2006, both would be on it.
>>
>> Does this make sense?
>>
>> Best regards,
>> Bart
>>
>> -----Oorspronkelijk bericht-----
>> Van: UMN MapServer Users List
>> [mailto:MAPSERVER-USERS at LISTS.UMN.EDU]Namens Yewondwossen Assefa
>> Verzonden: donderdag 27 juli 2006 3:35
>> Aan: MAPSERVER-USERS at LISTS.UMN.EDU
>> Onderwerp: Re: [UMN_MAPSERVER-USERS] WMS time question
>>
>>
>> Bart,
>>
>>
>> Bart van den Eijnden (OSGIS) wrote:
>>
>>> Hi list,
>>>
>>> looking through the Mapserver WMS time HOWTO I wondered one thing, 
>>> it is
>>> only possible to have 1 timeitem, a DB column which contains the
>>> date/time. Ofcourse this is pretty okay for satellite images (in a
>>> tileindex) which are taken every X days/months.
>>>
>>> But what happens to road network segments (geometries in Oracle Spatial
>>> for instance) which have a minimum date and a maximum date? So you 
>>> need to
>>> specify 2 timeitems (one min and one max) for that. Was this use 
>>> case just
>>> not implemented?
>>>
>>
>>
>>   What would the min/max date represent : the valid time extents or 
>> simply 2 time fields on which we can do a query ?
>> The wms request allows to  send a time value that is then compared to 
>> the value inside the timeitem. Would you expect to be able to compare 
>> the time request between the 2 timeitmes defined ?
>>
>>
>>> Best regards,
>>> Bart
>>>
>>
>>
>>
>
>


-- 
Bart van den Eijnden
OSGIS, Open Source GIS
http://www.osgis.nl



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