[mapserver-dev] Advanced Selection Management API

[Paul Spencer]

Thanks Steve, I'll discuss with Assefa as he would be the one to do the actual design, RFC and implementation if there seems to be a general consensus that this would be a desirable feature in mapserver

Cheers

Paul

On 2009-12-07, at 6:13 PM, Steve Lime wrote:

> Thinking about this from the query file point of view you can do all of this except for modifying
> a result set. The 5.6 code actually caches a query parameters in a query file rather than an id
> list in the past. It's faster for many data providers just to redo a query than deal with the get
> feature by id queries. I've used the new query file to persist query results and it works fine.
> 
> Modifying a selection set would require some sort of disk serialization as you suggest. It would be
> cool to be able to serialize a query as a data set (as opposed to just the parameters) and then
> support operations against that data set based on other queries (subtraction or addition). 
> You'd draw the data just like any other layer. Using query results (either stock MapServer or
> WFS) as a way to create, add or remove features from a selection set would be pretty convenient.
> 
> I think this would be a desirable addition.  I do wonder if a shapefile is flexible enough though 
> given things like DBF size and type limitations...
> 
> Steve
> 
>>>> On 12/7/2009 at 12:43 PM, in message
> <14FB35AD-D104-4755-AEE5-73DB0FD2DAD9 at dmsolutions.ca>, Paul Spencer
> <pspencer at dmsolutions.ca> wrote:
>> We have a customer for which there is a need for some more advanced selection 
>> management functionality.  The basic requirements are:
>> 
>> * create a new selection from a set of features selected spatially or by 
>> some combination of attributes
>> * save a named selection (serialize to disk file)
>> * restore a previously saved selection (deserialize from disk file)
>> * modify a selection by adding or removing features selected spatially or by 
>> some combination of attributes
>> * highlight a selection when drawing using the CGI (like referencing a .qy 
>> file)
>> * access features in the selection for other aspects of the application
>> 
>> My questions:
>> 
>> 1) is this achievable with the current setup?  I don't think so, the only 
>> way I can think to do this is to use mapscript to create shapefiles of 
>> selected features and manage selection as separate datasources and layers
>> 
>> 2) is this something that would be desirable to have in mapserver/mapscript 
>> or should I just look at doing my own thing on the side?
>> 
>> 
>> Cheers
>> 
>> Paul
>> __________________________________________
>> 
>>   Paul Spencer
>>   Chief Technology Officer
>>   DM Solutions Group Inc
>>   http://research.dmsolutions.ca/ 
>> 
>> _______________________________________________
>> mapserver-dev mailing list
>> mapserver-dev at lists.osgeo.org 
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> 


__________________________________________

   Paul Spencer
   Chief Technology Officer
   DM Solutions Group Inc
   http://research.dmsolutions.ca/