Defining coordinate queries

Coordinate queries can find entities or links of a particular type within a defined geographic area or close to a location.

About this task

You can use coordinate queries to search entities or link types that have coordinate fields. You can only run coordinate queries on entity or link types that have a Coordinate type field, followed by two real number fields that contain coordinate data.

Procedure

  1. Select Analysis > Coordinate Query Builder.

  2. Select the entity or link type that contains the coordinate data.

  3. Select the Coordinate type field. This will typically be selected automatically, as there is usually only a single Coordinate field for each entity or link type.

  4. In the Source area, specify which records you want to include in the coordinate query.

  5. In the Query Operator area, select the required operator:

    • Is near - finds records with coordinate data that is within a specified distance of a location you enter. Enter the location using coordinates and then specify the required distance and units.

    • Is between - finds records with coordinate data that falls within a rectangle whose corners you define. Enter the two sets of coordinates to form the corners of the search area.

  6. In the Coordinates area, enter the coordinates

    If you selected 'Is near', enter one set of coordinates, then enter a value in the Tolerance box and the units for that value, such as Feet, Kilometers, Miles, Seconds, or Yards. This value is used to calculate the distance from the entered coordinates. The use of seconds as a unit is a way to specify small distances. Each degree is divided into 60 minutes, and each minute is divided into 60 seconds. If you, for example, set a tolerance of 30 seconds on a latitude of 38 degrees, the tolerance will be 30/3600 = 0.0083333 degrees.

    The Tolerance is calculated by adding the specified distance to both the horizontal (longitude) and vertical (latitude) part of the coordinates to create a square with the original coordinates in the middle. Any record with coordinates that are located within this square is found.

    If you selected 'Is between', enter two sets of coordinates. These coordinates form two corners of a rectangle. Records with coordinates that fall within the defined square are found.

  7. Click Next to create the query.

  8. Click Results to run the query.