[mapserver-dev] incorrect layer drawing order issue

[Tamas Szekeres]

Yes that would be the simplest approach in short term.
But I think it would also be reasonable to get it configurable for all
supported drivers, through mapfile and mapscript.

Best regards,

Tamas



2014-11-09 20:49 GMT+01:00 geographika <geographika at gmail.com>:

>  Would a SORTBY clause be added as a keyword in the DATA statement?
> E.g. DATA "ogr_geometry from rivers USING UNIQUE ogr_fid USING SRID=4326
> USING SORTBY my_sort_fieldname"
>
>
> On 07/11/2014 12:49, Tamas Szekeres wrote:
>
> We could also extend the DATA section with a SORTBY clause for the mssql
> driver.
> Adding this feature to MSSQL (as per RFC 105) would anyway be fairly easy.
>
>  Tamas
>
>
>
>
> 2014-11-07 11:24 GMT+01:00 geographika <geographika at gmail.com>:
>
>>  Hi list,
>>
>> I have come across an issue that is critical to the project I am working
>> on and wondered if it applies to all database drivers or just the SQL
>> Server 2008 one.
>>
>> I have logged the issue on GitHub at:
>> https://github.com/mapserver/mapserver/issues/5008
>>
>> I will try some tests over the weekend to see if the Postgres driver
>> works the same way, but there seems to be no way of guaranteeing feature
>> display order - even if all documentation suggests it can be achieved in a
>> database layer using "ORDER BY"
>> Whilst for a low number of records the order seems ordered, with 150+
>> features I get different images returned each time by my WMS service. No
>> use of clustered indexes, partition statements etc. can get around this as
>> SQL result sets can only be guaranteed with an ORDER BY in the outermost
>> statement.
>>
>> I note that in http://mapserver.org/fr/development/rfc/ms-rfc-105.html
>> there is a new function msLayerBuildSQLOrderBy() that allows sorting to be
>> done outside of the layer's DATA statement for WFS requests with a SORTBY
>> parameter. Maybe this could also be used by a new LAYER "SORT" config
>> keyword?
>>
>> I see the above is only implemented for a few drivers. The client would
>> be willing to fund adding this to the SQL Server driver if there are any
>> core devs interested in doing this.
>>
>> Regards,
>>
>> Seth
>>
>>  --
>> web: http://geographika.co.uk
>> twitter: @geographika
>>
>>
>>
>
>
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