Hello,
This is being
done using php-mapscript (4.8), by querying a SQL Server database,
there were some mails a few weeks ago about speed and database
connections on this list. Look for: "performance with different data
formats" (date: about Aug, 20-23). Perhaps this applies to your problem too.
if we don't try to colour the
polygons, the map displays very fast.
Could you put for a test the data into the dbf file of this layer? It
would be interesting to see if there a difference in speed when not
using a database connection.
EXPRESSION /^158$|^162$|^163$/
I don't think, that your problem with speed is because of your regular
exp. But since you have only a few classes, could you add a new field to
the database with a number from 1..n corresponding to your classen and
use this number field as CLASSITEM? Only to see if there is a difference.
Manfred
Ben Madin schrieb:
G'day all,
We are generating a map showing relative densities in various polygons
(worldwide adminstrative regions) of various commodities. This is being
done using php-mapscript (4.8), by querying a SQL Server database,
developing a range to code, and generating classes below. The shapefile
does not have any of the data associated with it, only the id which
matches up with that in the db.
When we do this at a country level (242 countries) there is little
trouble with speed - maybe a few seconds.
However, at the next level (3300 administrative regions) this is taking
way too long. Through various testing, the only step that is taking
longer than 1 second is the
$img = $map->draw();
step, which can take upwards of 15 seconds - very tedious for a user.
(Originally we tried it using reprojection (to orthographic) it was
routinely taking > 3 minutes!, so sadly that has been dropped.)
I accept that the shapefile is large (90MB), and some time will be
required, but this seems way to long. if we don't try to colour the
polygons, the map displays very fast.
I have attached the class definitions for a part of the mapfile which is
generated. The CLASSITEM is the polygon id. Any suggestions??
CLASS
NAME "< 7040000 /sq km"
EXPRESSION /^$/
METADATA
END
STYLE
ANGLE 360
COLOR 0 204 51
SYMBOL 0
END
END
CLASS
NAME "< 5280000 /sq km"
EXPRESSION /^157$/
METADATA
END
STYLE
ANGLE 360
COLOR 0 153 102
SYMBOL 0
END
END
CLASS
NAME "< 3520000 /sq km"
EXPRESSION /^158$|^162$|^163$/
METADATA
END
STYLE
ANGLE 360
COLOR 0 102 153
SYMBOL 0
END
END
CLASS
NAME "< 1760000 /sq km"
EXPRESSION /^156$|^160$|^161$/
METADATA
END
STYLE
ANGLE 360
COLOR 0 51 204
SYMBOL 0
END
END
CLASS
NAME " 0 "
EXPRESSION /^$/
METADATA
END
STYLE
ANGLE 360
COLOR 0 0 255
SYMBOL 0
END
END
CLASS
NAME "No Data"
EXPRESSION /^$/
METADATA
END
STYLE
ANGLE 360
COLOR 255 250 205
SYMBOL 0
END
END
cheers
Ben
--
Ben Madin
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