[mapserver-users] WCS time support bugs

[Armin Burger]

Alex

during the tests I noticed 2 shortcomings of the patch for the 
'wcs_timeposition', both are a bit correlated with each other:

If a request contains a timestamp not available in the Postgis table 
then an empty image will be sent back to the requesting client. A better 
solution would be to check the available dates in the PG table and 
return a service exception in case the requested date is not there.

Another problem is that clients will have no possibility to know which 
dates are really available when supplied with a range. The only WCS 
client I found so far that supports WCS-T is gvSIG. But this client just 
offers the time range definition for selection, so it will not work. A 
solution could be that the DescribeCoverage response reads all available 
timestamps from the tileindex layer and returns a single entry for all 
of them in the returned XML.

Both modifications would require to dive somewhat deeper into the code 
and understand where and how the link between WCS layer and tileindex 
layer is made and how the info from the PG tileindex layer is retrieved 
from PG. I unfortunately doubt that this will be of high priority to the 
main developers.

Greetings, Armin



On 10/11/2008 17:33, Alexander Petkov wrote:
> On Wed, Nov 5, 2008 at 11:39 AM, Alexander Petkov <greenkov at gmail.com> wrote:
>> On Wed, Nov 5, 2008 at 10:13 AM, Armin Burger <armin.burger at gmx.net> wrote:
>>> Alex
>>>
>>> I had a look at the code and tried the suggested fix. I uploaded a patch at
>>> the wiki, see this link
>>> http://trac.osgeo.org/mapserver/attachment/ticket/2487/mapwcs.c.patch
>>>
>>> With these modifications the PostGIS problem disappeared and it was also
>>> possible to specify 'wcs_timeposition' as a range of dates instead of single
>>> dates for the full timeseries.
>>>
>>> Armin
>> Awesome, thanks Armin!!
>>
>> I will patch and use,
>>
>> Alex
>>
> 
> The patch is very useful indeed :) GetCoverage requests now work for
> Postgis-backed time indexed layers with this patch. Also, now I don't
> need to specify explicit time positions for the wcs service--just
> start and end.
> 
> Hopefully it'll make it into the source tree.
> Thanks again,
> Alex
>