XMap GIS Enterprise offers two powerful tools for deploying data within a company or organization and, consequently, for collecting field data edits and integrating them into a central GIS database. Both Synchronization and Check-out/in involve the transfer of OpenSpace GIS layers from an Enterprise database to remote XMap users; however, the two data transfer processes and the functionality they enable for the recipients are significantly different. This article will cast some light on these two powerful functions of the XMap GIS suite and will help you decide which would be a more appropriate solution for your data deployment needs.
Synchronization
XMap’s synchronization process provides a simple tool for field personnel to automatically receive updates to GIS layers to which they have subscribed. The initial setup involves assigning access to the Enterprise database for each required user or each member of a designated Windows® group. This process is managed using XMap’s Database Manager application, which can be accessed from the Workspace in the GIS tab. A subscription file is generated and sent to each user for the purpose of establishing synchronization between their local XMap database and the central database. This process is initiated by simply double-clicking the file after it has been received.
Each user or group can be assigned a unique combination of layers by the data administrator and this selection can be modified at any time without the need to update the subscription file. For instance, if a field worker is reassigned to a new territory, the data administrator can simply clear the check boxes for the layers to which he or she was previously subscribed and then select the layers that are appropriate for their new assignment. Next time synchronization is initiated, the old layers will be removed and the new layers will be added to their Workspace.
Synchronization was originally designed as a means for field technicians to receive continually updated layers in a read-only format. In other words, regardless of which version of XMap is being used, the database that is automatically created to receive the synchronized layers does not offer editing functionality. However, the process does enable a redlining function that allows onscreen mark-ups to automatically be submitted to the Enterprise database during synchronization. These redline layers are essentially draw layers that can be scrutinized by the GIS manager to help ascertain if the referenced GIS data should be updated.
With the introduction of the optional XMap Forms capability in XMap 7, synchronization has assumed a higher level of functionality. If XMap Forms is enabled for a database user and a preformatted form is deployed along with a synchronized layer, the field worker can edit or collect new data points and can assign attributes based on any constraints that have been imposed by the data administrator. Edits to the data are then automatically applied to the original layer in the Enterprise database during synchronization. XMap Forms transforms synchronization from a remote data viewing function to a full data collection tool.
Data Check-Out/In
The data check-out and check-in process was developed to provide multiple XMap users the means to concurrently edit a single layer by assigning a specific geographic territory to each user. Multiple check-outs can be created from a single layer however their geographic coverage cannot overlap. When an individual is working within a defined territory, no one else can update any of the GIS objects within that area until that section is checked in.
The act of checking out a portion of a layer creates a new subset of the original layer that can be copied to a remote database while locking the assigned territory in the original layer. The new layer inherits all of the properties of the original including the available attribute fields, the classification and symbolization settings, and any queries that have been created. Most importantly, the recipient of a checked-out layer has full control over the geometric characteristics and the attributes of the layer and can add, delete, or edit points, lines, or polygons. For this reason, the check-out/in process typically involves the transfer of data between the Enterprise and Editor versions of XMap. There is limited value in checking out a layer to a user of XMap Professional because that application does not provide the requisite editing functionality.
The data check-out process is managed using the Check-out/in function in either the Enterprise or Editor versions of XMap, although the originating layer must be in an Enterprise database. A scalable grid is used to select specific tiles of data on the map and after the new layer is created, the assigned grids are highlighted to indicate their contents and cannot be edited or concurrently checked out to another XMap user.
The checked out layer must be assigned to a database other than the one containing the original layer. A data administrator can either create a new database on the same SQL server or, with the appropriate permissions, can create the layer in the local database of the end user. After this new layer has been created, the remote XMap user can update the geometric and attribute values of the layer within the assigned geographic limits.
Before an updated section of a layer is checked in, the data administrator can add it to their workspace to ascertain the quality of the work. If it is deemed acceptable, they can simply click the Check-in button to replace the original data with the updated features from the checked out layer. If it is not acceptable, they can click the Cancel button, which restores the layer to its original form and unlocks the formerly locked area. In either case, the checked out layer is automatically deleted from the remote database.
Which Data Distribution Mechanism Works Best?
There are advantages to both data transfer processes and the decision as to which to choose depends on several factors:
Synchronization may be a better solution if:
- The number of targeted field users is relatively large as data can be simultaneously distributed to many individual users
- There is likely to be more than one person working within a specific area
- The field workers are using XMap Professional
- The data layers in question are frequently updated
- The data manager wishes to control the editing of the layers through the deployment of XMap Forms
- The administrator wants to enable the field workers to initiate the transfer process when they are in a connected environment rather than manually assigning and collecting the appropriate layers from each user
Check-out/in is worth considering if:
- The number of users is relatively small and the transfer process can be initiated manually
- The data manager wishes to provide full editing control for all data types
- The field workers have access to either XMap GIS Editor or Enterprise
- There is a need to protect the data while one individual is working in an area to avoid potential conflicts
- The administrator wishes to see and verify the data edits before the field-collected information is merged into the original layer
What these components of XMap have in common is that they were both designed to streamline the flow of information within an organization and ultimately to make the task of sending and receiving data significantly more straightforward for GIS managers.
