Autodesk 15606-011408-9320 - MAPGUIDE R6.3 CPU MODEL-UPG 4/5 MIN 2 CPUS INITL User Manual page 58

Map Authoring


Show only the layers that users really need. You can make the layers avail-
able but not visible when the user first displays the map, reducing the
amount of data that needs to be processed when the map is first loaded.


Create static layers for small, frequently accessed data that does not need
to be kept secure. Static layers are loaded only once; zooming in and out
on the layer does not send requests to the server. For larger data sets, data
that changes frequently, and data that needs to be kept secure, use
dynamic layers instead.


Use the Display Ranges option and pyramid the data. This involves creat-
ing multiple layers that show the same data but at different resolutions.
You might have one layer that displays very detailed data and appears
only when the user is zoomed in close, a second layer that displays less
detail and appears only when the user is zoomed out farther, and a third
layer that shows very generalized data and displays only when the user is
zoomed out quite far.
Data Preparation


For point and text layers, rather than creating an SDF for the points and
linking it to a SQL table for the attribute data, consider storing the points
in the SQL table as well and using that table as the source for the layer.
Whenever you link an SDF to a SQL table, it takes longer to process than
a layer based on just an SDF or a SQL table. This is not true of themes, how-
ever. When setting up a theme, it doesn't matter whether the data source
and theme source are the same SQL table, or the data source is an SDF and
the theme source is a SQL table—performance will be the same in both
cases.


If there are multiple theme categories for a layer, consider using separate
layers that reference separate SDFs. If possible, you could also export the
information in a SQL table to a comma-separated (CSV) file and import it
into its own SDF, rather than including it as a theme category of a layer
based on another SDF.


Generalize data as much as possible. This involves reducing the resolution
of the data so that there is less data to process. You can generalize SDFs
using Autodesk MapGuide SDF Loader or Autodesk MapGuide SDF Com-
ponent Toolkit; you can sub-sample raster images using Autodesk
MapGuide Raster Workshop. Note that generalization reduces the amount
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58 Chapter 3 Designing Your System