How can Create OVF file (for OGR MYSQL connection) interactively

[Bart van den Eijnden (OSGIS)]

David,

my guess without studying the code is that this does not make a 
difference in performance.

I think a Mapserver EXPRESSION will make it into the SQL that OGR passes 
to MySQL in the end. I don't believe Mapserver does the filtering itself 
on the whole dataset.

Best regards,
Bart

Fawcett, David schreef:
> Bart, 
>
> I am assuming that this method would be faster than requesting the whole
> table from MySQL and then using variable substitution to set an
> expression for a class that displays only the record of interest.  
>
> I know that it would be faster to only pass the data that is needed, I
> am more curious about whether the OGR/MySQL query mechanism is better or
> worse than 'filtering' with a mapfile expression.  
>
> David.
>
> -----Original Message-----
> From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
> Behalf Of Bart van den Eijnden (OSGIS)
> Sent: Tuesday, September 19, 2006 2:31 AM
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] How can Create OVF file (for OGR
> MYSQL connection) interactively
>
>
> See:
>
> http://mapserver.gis.umn.edu/cgi-bin/wiki.pl?VirtualSpatialData
>
> Section: Dynamic Control of Virtual Sources
>
> Best regards,
> Bart
>
>   
>>  Dear friends;
>>
>>  Finally I have solved to read point data form mysql database than 
>> draw map by using  those data.
>>  I have created Peak Ground Acceleration (PGA) map for the specified
>> earthquake which data are
>>  stored in MySql. But I would like to display map for all earthquake
>>     
> which
>   
>> are
>>  described in the Mysql table as eq-id column.I mean PGA data are
>>     
> stored
>   
>> in mysql database.table for several earthquakes
>> and one of the column is called EQ_ID which use for the seperate PGA
>>     
> data
>   
>> from other earthquake like
>> EQ_ID            Lon   Lat     PGA
>> 200006060242 30.40 32.45 2.5
>> 200006060242 30.41 32.46 2.6
>> 200006060242 30.42 32.47 2.7
>> ...
>> 200606071708 38.45 40.98 5.6
>> 200606071708 38.46 40.99 5.7
>> 200606071708 38.47 41.00 5.7
>> 200606071708 38.48 41.01 5.8
>> .
>> .
>> .
>>  I have querid mysql database by using ovf file as following
>>
>>  <OGRVRTDataSource>
>>  <OGRVRTLayer name="acceleration">
>>
>>  
>>
>>     
> <SrcDataSource>MYSQL:database,user=user,password=pass_wd,host=100.00.00.
> 21,port=3306,tables=d_pgadata1</SrcDataSource>
>   
>>  <SrcSQL>SELECT eq_id,latitude,longitude,acceleration from d_pgadata1
>>  where eq_id like '%200006060242%' </SrcSQL>
>>  <GeometryType>wkbPoint</GeometryType>
>>  <GeometryField encoding="PointFromColumns" x="longitude"
>>     
> y="latitude"/>
>   
>>  </OGRVRTLayer>
>>  </OGRVRTDataSource>
>>
>>  As you see when I create map by layer OGR this will just the eq_id 
>> like  '%200006060242%'.  But I would like to change this eq_id by 
>> interactively for example who will
>>  like to see 200606071708 earthquake PGA map he/she can change sql
>> statement in
>>  ovf file by using php or html commands from web...
>>
>>  Do you have any idea is it possible or not.
>>
>>  Please I wellcome any kind of information about it..
>>  Thank you
>>  Murat
>>
>>
>>
>> --
>> This message has been scanned for viruses and
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>>
>>
>>     
>
>
>
>   


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