An Example for Spatial Query

Sample data used in this example is the China400.udb datasource. The road, lake, and administrative region data are involved. Query:

• Lakes contained in Hunan province.
• Roads that passes by Hunan province with the road code of G320.

Basic Steps:

1. Open the China.udb datasource in the current workspace.
2. Create a new map window and add the three datasets ProvincesR, LakeR, and Road_L to the newly created map window.
3. In the map window, select the region indicating the Hunnan province in the Provinces_R layer, that is the searching object.
4. On the Spatial Analysis tab, in the Query group, click Spatial Query to open the Spatial Query dialog box.

5. Specify the spatial query condition and attribute query condition for the searched layer.

   • Click the Spatial Query Condition dropdown button for the RoadL layer in the layer list and select “IntersectRegionLine” to query roads that pass by Hunan.
   • Click the Attirbute Query Condition dropdown button for the RoadL layer in the layer list, click “Expression”, and compose the SQL expression RoadL.CODE = “G320” in the dialog box that shows up.
   • Click the Spatial Query Condition dropdown button for the LakeR layer in the layer list and select “ContainRegionRegion” to query lakes in Hunan province.
6. Select the RoadL and LakeR layers, check the Browse in Attribute Table, Highlight in Map, and Highlight in Scene boxes.
7. Select the RoadL, check the Save Results box, specify the target datasource as China.udb, and rename the result dataset as “HunnanRoadG320”.

Similarly, rename the result dataset for the Lake_R layer as “HunanLake”.

8. Click OK to perform the SQL query.
9. Browse the query results in the attribute table, on the map, and in the scene simultaneously. Select a record in the result to realize linkage browsing.