Managing Spatial Data Sources

The tasks presented in this section can be performed from the configuration interface of a particular SDS or from the Spatial Data section, by selecting one or more SDSs in the table.

Updating spatial data sources

Before a spatial data source can be used to create layers, it must be updated. In JMap, updating a data source generally involves collecting information on the spatial data and its attributes and preparing data for fast and efficient access. This process may be very brief or may take several minutes, depending on the type of data source and amount of data.

In concrete terms, this operation involves different tasks, depending on the type of data source. Generally speaking, for data sources that access data stored in files, the contents are read by JMap Server and inserted in the tables of JMap’s System database. A spatial index is then built for fast access, and attribute statistics are calculated.

For data sources that access data stored on spatial data servers like Oracle Spatial/Locator or WFS systems, the update process is simpler and only involves calculating attribute statistics.

Updating file data sources takes more time than updating server data sources.

You can update several data sources simultaneously. A maximum of three data sources can be updated at a time. Other data sources that need to be updated are placed on hold until their update can be performed.

Scheduling automatic data source updates

You can schedule automatic updates for spatial data sources. This action may be helpful if you use data sources that read data files. If the files are frequently modified, you can schedule automatic updates that will occur on a regular basis (every day at midnight, for instance) for the appropriate data sources. Each data source can have its own schedule.

In order to schedule updates for a given data source, click on the icon of the Update schedule from that data source’s details section or select it in the table of data sources. Afterwards, simply follow the wizard to define the specific moments when the updates will take place. Scheduling options are very flexible.

Once these tasks have been scheduled, you can view the current schedule for a data source by viewing its information section.

At any time, you can access the list of all planned updates for data sources by clicking on Scheduler in the Tools section.

Deleting spatial data sources

When a data source has been deleted, its entire configuration is permanently deleted. The data itself (the file or database) is not affected.

Statuses of spatial data sources

Each spatial data source has a status. The status indicates the condition of the data source, i.e. if it is ready to be used, if an error occurred, etc.

The status of a newly created data source is always set to not ready (unless you checked the auto-update flag). This means that the data source cannot be used yet. In order to be used, every data source must be updated at least once.

Data sources can be updated in batches. A maximum of 3 data sources can be updated simultaneously. Other data sources to be updated are queued until they can be updated.

The following table describes the possible statuses of a spatial data source:

Statuses
Error	An error occurred. The data source cannot handle requests. See error message to determine the source of the error.
Job queued	The data source is waiting to be updated. A maximum of 3 data sources can be updated simultaneously. The data source can still handle requests if it was updated at least once before.
Update needed	The configuration of the data source has been modified and it must be updated before the changes are effective. The data source can still handle requests.
Not ready	The data source is not ready to handle requests. This status is typically attributed to a data source that has just been created but has not yet been updated.
Ready	The data source is ready to handle requests.
Updating	The data source is being updated. Depending on the type of data source and volume of data, the update process can be very fast or it can take a certain amount of time. The data source can still handle requests if it was updated at least once before.