[postgis-users] Postgis and open layers

[Gustavo Ces]

Hi Luigi,

    i was reading about WPS with postgis, and only found python based solutions. I prefer a java based one, but 52 north web page is not as clear as i' would need.  I´ll install the framework and look at examples included... But i don´t need to post my processing services, just make queries with some of them to been used with open layers (routing, buffers, or more complicated postgis queries). So a usual java code will be a simpler approach..
    The problems with views are dynamic parameters of functions like StBuffer(the_geom,distance).... You can change the_geom dynamically with a view... On second thougths, maybe de distance could be read from another table.... Then i have to serve the view as a WMS or WFS and it will be updated with distace_table automatically... So when you change the_geom_table or distance_table the wms posted view will automatically updated, don´t you?
    Performance? No idea... I have to do some experiments first! :)

Gus
  ----- Original Message ----- 
  From: Luigi Castro Cardeles 
  To: PostGIS Users Discussion 
  Sent: Wednesday, August 27, 2008 4:08 PM
  Subject: Re: [postgis-users] Postgis and open layers


  Hi,

  hum, maybe what you want with st_buffer is a WPS? this service let you do dynamic stuff with your data. But integrate this with openlayers... i don't do that... yet :D.

  if your data are in postgis, you could put a WFS or WMS, with many tables. You can create a temp table, or a view from a select (passing the variables via a form) and them you put that view at mapserver (add an entry in geometry_columns for that view). 
  If you don't want to edit your data (change the vectors) you could make many WMS and put a view(created from a buffer) in a another WMS, so when the user want to do a buffer stuff, he do that only at that table or some features from that table. 

  Making a dynamic buffer can turn in a performance nightmare... i think. 

  Maybe you could cache some buffer to gain speed. just some ideas.

  []'s


  2008/8/27 Gustavo Ces <g.ces at pettra.es>

    Hi Luigi,

        but with WFS  i´ll have to create the table for each query and serve that table, won´t i? I don´t know very well WFS, but if a i want to make a buffer table with ST_buffer ( for example) i have to create a table and then serve it as WFS ( automatically, coding it in my application). If a i need to change the distance in St_Buffer funcion, then i have to recreate that table and serve it as WFS... or maybe there is a something in WFS specification to make these types of querys? ( not queries over the result table!)
    What i want to do is postgis analysis capacity viewed in open layers. Maybe there is a better solution...
    Thanks for answering,

    Gus
      ----- Original Message ----- 
      From: Luigi Castro Cardeles 
      To: PostGIS Users Discussion 
      Sent: Tuesday, August 26, 2008 5:17 PM
      Subject: Re: [postgis-users] Postgis and open layers


      Hi,

      try to create wms and wfs. They are supported by openlayers.
      []'s


      2008/8/26 Gustavo Ces <g.ces at pettra.es>

        Hi all,

            i was searching info about viewing postgis data in openlayers. Which would be the better approach to draw dynamic queries in postgis? Views not valid to me because needed queries with variables. 
            One solution could be making with dynamic web language the query to create an asGML/KML/... file and then render it in open layers... Any other idea?
            Thanks in advance,

        Gus

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      -- 
      Luigi Castro Cardeles



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