maps.google.com - Speed

[Shanton, James A]

We're using a SQL Server DB, and OGR to access the coordinates to plot our
items.   Listed below is the info out of the connection file.   Is this
similar / comparable in speed to a PostGIS database ?

Are there any ways I can speed this up ?    We have indexes on the activity,
ag_latitude, and ag_longitude columns.

I'm also displaying the activity on the map with different colors, by using
classitem "atvstatus" listed in the mapfile section below.

Thanks !
Jim

-------------------------------------- ovf File (Db Connection) --------

<OGRVRTDataSource>
    <OGRVRTLayer name="actsogrl">
        <SrcDataSource>ODBC:myuid/mypwd at mydevDB</SrcDataSource>
        <SrcLayer>idsites</SrcLayer>
       <SrcSQL>select
activity,rspprty,atvtype,customer,agreement,atvstatus,milepost,ag_latitude
as y,ag_longitude as x,image_file from re_activity_coordinates where atvType
not like '%signboard%'</SrcSQL>
        <GeometryType>wkbPoint</GeometryType>
        <LayerSRS>WGS84</LayerSRS>
        <GeometryField encoding="PointFromColumns" x="x" y="y"/>
    </OGRVRTLayer>
</OGRVRTDataSource>



--------------------------------------------  Map File Section Below ------

LAYER
    NAME "acts"
    TYPE POINT
    CONNECTIONTYPE OGR
    CONNECTION "ogrActs.ovf" # the name and path to the virtual.ovf file,
relative to shapepath may work?
    DATA "actsogrl" # the name of the OGRVrtLayer
    STATUS OFF
   SYMBOLSCALE 50000

   DUMP TRUE
   TOLERANCE 30

   LABELITEM activity #may need to use table.name or just name depending on
your OVF file.
   CLASSITEM "atvstatus"  # value to be compared to EXPRESSION
   CLASS #activities
     NAME "Completed Activities"  # will show up in index this way
     EXPRESSION 'Completed'  # String to compare to Attribute column
     SYMBOL 'circle'
     SIZE 7
     MINSIZE 2
     MAXSIZE 20
     COLOR 255 0 0
     OVERLAYSYMBOL 'circle'
     OVERLAYSIZE 1
     OVERLAYCOLOR 255 0 0
     LABEL
       type truetype
       FONT ARIAL-BOLD
       maxsize 10
       minsize 6
       COLOR 0 0 0
       OUTLINECOLOR 255 255 255
     END # end label
   END
   CLASS #Active activities  -- Lime Green
     NAME "Active Activities"  # will show up in index this way
     EXPRESSION 'Active'  # String to compare to Attribute column
     SYMBOL 'circle'
     SIZE 7
     MINSIZE 2
     MAXSIZE 20
     COLOR 0 255 0
     OVERLAYSYMBOL 'circle'
     OVERLAYSIZE 1
     OVERLAYCOLOR 0 255 0
     LABEL
       type truetype
       FONT ARIAL-BOLD
       maxsize 10
       minsize 6
       COLOR 0 0 0
       OUTLINECOLOR 255 255 255
     END # end label
   END
   CLASS #Canceled activities   -- BLack
     NAME "Canceled Activities"  # will show up in index this way
     EXPRESSION 'Active'  # String to compare to Attribute column
     SYMBOL 'circle'
     SIZE 7
     MINSIZE 2
     MAXSIZE 20
     COLOR 0 0 0
     OVERLAYSYMBOL 'circle'
     OVERLAYSIZE 1
     OVERLAYCOLOR 0 0 0
     LABEL
       type truetype
       FONT ARIAL-BOLD
       maxsize 10
       minsize 6
       COLOR 0 0 0
       OUTLINECOLOR 255 255 255
     END # end label
   END
   CLASS #Other activities   - Blue
     NAME "Other Activities"  # will show up in index this way
     EXPRESSION 'Other'  # String to compare to Attribute column
     SYMBOL 'circle'
     SIZE 7
     MINSIZE 2
     MAXSIZE 20
     COLOR 0 0 255
     OVERLAYSYMBOL 'circle'
     OVERLAYSIZE 1
     OVERLAYCOLOR 0 0 255
     LABEL
       type truetype
       FONT ARIAL-BOLD
       maxsize 10
       minsize 6
       COLOR 0 0 0
       OUTLINECOLOR 255 255 255
     END # end label
   END

END



-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Gregor Mosheh
Sent: Monday, April 11, 2005 7:24 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] maps.google.com - Speed

--- "Shanton, James A" <James.Shanton2 at NSCORP.COM>
wrote:
> Is there anyway to speed this system up like
> maps.google.com  ?  I'm having
> speed issues displaying my database layers.

I presume you mean PostGIS tables. For starters, make
sure you have the appropriate indexes created on your
PostGIS table. There are basicallly three indexes to
consider:

- an index on the oid column. this is used internally
by MapServer and PostGIS and makes a HUGE difference.

- a GIST index on the geometry column (probably called
the_geom) is obviously useful, and makes a huge
difference.

- if your layer uses a FILTER to select only certain
records, make sure those columns have indexes

I hope that helps.




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