Importing geospatial data into the Variable File Node

If the node contains geospatial data, was created as an export from a flat file, and is used in the same stream in which it was created, the node retains the geospatial metadata and no further configuration steps are needed.

However, if the node is exported and used in a different stream, the geospatial list data is automatically converted to a string format; you must follow some extra steps to restore the list storage type and the associated geospatial metadata.

For more information about lists, see List storage and associated measurement levels.

For more information about the details you can set as geospatial metadata, see Geospatial measurement sublevels.

To set up the geospatial metadata, use the following steps.

1. On the File tab of the Variable File node, select the Treat square brackets as lists check box. Selecting this check box means that the data included between opening and closing square brackets is treated as a single value, even if the content includes delimiter characters such as commas and double quotation marks. Failure to select this check box means that your data is read as a string storage type, any commas in the field are processed as delimiters, and your data structure is interpreted incorrectly.
2. If your data includes single or double quotation marks, select the Pair and discard option in the Single quotes and Double quotes fields, as appropriate.
3. On the Data tab of the Variable File node, for the geospatial data fields, select the Override check box, and change the Storage type from a string to a list.
4. By default, the list Storage type is set as a List of real and the underlying value storage type of the list field is set to Real. To change the underlying value storage type or the depth, click Specify… to display the Storage subdialog box.
5. In the Storage subdialog box you can modify the following settings:
   • Storage Specify the overall storage type of the data field. By default the storage type is set to List; however, the drop-down list contains all other storage types (String, Integer, Real, Date, Time, and Timestamp). If you select any storage type other than List, Value storage and Depth options are unavailable.
   • Value storage Specify the storage types of the elements in the list, as opposed to the field as a whole. When you import geospatial fields, the only relevant storage types are Real and Integer; the default setting is Real.
   • Depth Specify the depth of the list field. The required depth depends on the type of geospatial field and follows these criteria:
     • Point – 0
     • LineString – 1
     • Polygon – 1
     • MultiPoint – 1
     • MultiLineString – 2
     • MultiPolygon – 2
     Warning: You must know the type of geospatial field you are converting back into a list and the required depth for that kind of field. If this information is set incorrectly, it is not possible to use the field.
6. On the Types tab of the Variable File node, for the geospatial data field, ensure the Measurement cell contains the correct measurement level. To change the measurement level, in the Measurement cell, click Specify… to display the Values dialog box.
7. In the Values dialog box, the Measurement, Storage, and Depth for the list are displayed. Select the Specify values and labels option and, from the Type drop-down list, select the correct type for the Measurement. Depending on the Type, you might be prompted for more details such as if the data represents 2 or 3 dimensions and which coordinate system is used.

   For more information about coordinate systems, see Setting geospatial options for streams.