WMS/WFS and (yearly) time-dependent data

[Yewondwossen Assefa]

Stefan Schwarzer wrote:
> I am not (or better: hardly) working with raster data. All vector data. 
> National statistics for the whole world, like population density, gdp, 
> forest cover etc.
> 
> So, the each one of the 1000 or so (postgres) tables looks like this:
> 
> id     1970      1971   ....    2006
> 1        23.1        35.4   ....    45.6
> 2        12.3        10.9   ....    4.23
> ...
> 249 .....
> 
> and each id is then linked to another (postgis) table with the country 
> names and the geometry.
> 

  I think in this case the the wms time would not be a use for you.
  I think one possibility to look at would be to use the  run time 
substitution of Mapserver 
(http://mapserver.gis.umn.edu/docs/howto/runsub) .  You might be able to 
achieve that by using variables in an sql statement (that is part of 
the DATA value of your postgis layer) and have these variables 
substituted according to values in the request

Later,

> 
> 
>>  How is your data structured in postgis ? There is an example in the 
>> how using a postgis layer with a time field :
>> http://mapserver.gis.umn.edu/docs/howto/wms_time_support/#example-of-wms-t-with-postgis-tile-index-for-raster-imagery 
>>
>>
>>>> If your are serving layers as wms you could do soemthing like this :
>>>>
>>>>  - define a tileindex layer example:
>>>>
>>>>     LAYER
>>>>     NAME "mylayer"
>>>>     STATUS ON
>>>> #    TYPE POLYGON
>>>>     TYPE RASTER
>>>>   METADATA
>>>>     "DESCRIPTION" "mylayer"
>>>>     "wms_title" "mylayer"
>>>>     "wms_timeitem"  "time"
>>>>     "wms_timeextent"  "1970/2006"
>>>>      "WMS_SRS"   "epsg:4326"
>>>>   END
>>>>     SIZEUNITS PIXELS
>>>>     TILEINDEX "tile_file"
>>>>     TILEITEM "location"
>>>>
>>>>  - have a tile index that has at least 2 field (localtion for the 
>>>> files, and a time field) :
>>>>        location       time
>>>>      mypath/myfile    2005
>>>>       .....            ...
>>>>
>>>>  - doing a request of Getmap : something like
>>>>    GetMap&Version=1.1.1&LAYERS=mylayer&Time=2005
>>>>
>>>>  Not sure if that fits your model.
>>>>
>>>> Best Regards
>>>>
>>>>
>>>> Bart van den Eijnden (OSGIS) wrote:
>>>>> I think you should be looking at tile-indexing for the TIME 
>>>>> dimension. A
>>>>> field in the dbf of the tile-index will probably state which shapefile
>>>>> Mapserver needs to open for that specific year (and that specific 
>>>>> theme).
>>>>> I believe the WCS howto has some information on how to do this, but 
>>>>> I have
>>>>> no experience with this whatsoever:
>>>>> http://mapserver.gis.umn.edu/docs/howto/WCSServerFormatHowTo
>>>>> Best regards,
>>>>> Bart
>>>>> --Bart van den Eijnden
>>>>> OSGIS, Open Source GIS
>>>>> http://www.osgis.nl
>>>>> --------- Oorspronkelijk bericht --------
>>>>> Van: Stefan Schwarzer <stefan.schwarzer at GRID.UNEP.CH>
>>>>> Naar: MAPSERVER-USERS at LISTS.UMN.EDU <MAPSERVER-USERS at LISTS.UMN.EDU>
>>>>> Onderwerp: [UMN_MAPSERVER-USERS] WMS/WFS and (yearly) 
>>>>> time-dependent data
>>>>> Datum: 21/02/07 09:44
>>>>>> Hi,
>>>>>>
>>>>>> i read in a document ( http://mapserver.gis.umn.edu/docs/howto/ 
>>>>>> wms_time_support/view ) that there is a WMS/WFS-parameter one can  
>>>>>> specify for time dependent data. I am dealing mostly with 
>>>>>> statistical  data sets, which are covering a period of 1970 to 
>>>>>> 2006. So it should  be something like TIME=2004 to query a 
>>>>>> specific year.
>>>>>>
>>>>>> For each variable and year there is a five-classes breakup.
>>>>>>
>>>>>> It is not clear to me how I should set-up my map file. I guess, I  
>>>>>> could on one hand just have 36 layers (for each year a layer) - 
>>>>>> then  I wouldn't need the TIME parameter. But as I have some 1000 
>>>>>> files to  deal with, my map file would get pretty long...
>>>>>>
>>>>>> The other solution would be to have some kind of grouping classes, 
>>>>>> so  that all my years would fit into one layer, but into 36 classes.
>>>>>>
>>>>>> Or is there any kind of more &quot;dynamic&quot; solution?
>>>>>>
>>>>>> Thanks for any suggestions!
> 


-- 
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Assefa Yewondwossen
Software Analyst

Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
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