data is a fundamental GIS skill. There is usually an enormous amount
of source data available, whether it is in a set of attached DWG
files, or in a database. Typically, you want to work with only a
small subset of it. You limit the data that you have to work on
by running a query. The query finds the data you specify and brings
it into the current drawing.
you may want to bring in all the data in a certain geographic area by
drawing a rectangle or a circle on your base map. This is called
a location-based query (shown in the center of the illustration
other tasks, the data you want is a single feature class, such as
all parcels, and sometimes it is a more specific subset, such as
all parcels with value greater than a certain amount. These are
called property-based queries (shown on the right in the illustration
Map 3D, you can run queries to bring in data from a set of attached
DWG files, or from virtually any FDO-accessed data store:
- For DWG files, the query functionality
is available on the Map Explorer task pane. As well as creating
and running the current query, you can store any number of named
queries in the DWG file, save queries for reuse, and load queries
stored in external files.
The following example
shows a location-based query. It uses a rectangle to bring in all
the data inside a specific area of the source DWGs.
me how to run a query on a set of attached DWG files
- When you connect to a data store using
an FDO provider, the query dialog box appears when you click Add
to Map with Query to bring the feature class into your map. You
can then specify the subset of features that you want to work with.
The following example shows a property-based
query. It brings in all of the parcels that have a land value greater
me how to run a query on a feature class