Location

farmOS can track the physical location of Assets over time. This includes map geometry as well as relation to other Assets.

Fixed Assets

Some Assets are fixed in location. The geometry of these Assets is intrinsic to the Asset itself.

Land is an example of an Asset with a fixed location. Although geography changes over time, land assets in farmOS should be considered a snapshot of the physical land they represent at the current time. This is useful because it provides a simplified model for referring to a logical piece of land and its geometry.

Changes to a fixed Asset's intrinsic geometry should be limited to minor updates or corrections. If the changes are more substantial, a new Asset should be created, and the old Asset archived, to demarcate it as a new phase of the place in question.

Movable Assets

If an Asset is not fixed, then it is considered movable, and its location and geometry will be determined by movement Logs that reference it.

In order to set or change a movable Asset's location, a movement Log must be created that defines its new location at that point in time.

Any Log can be a movement. It just needs to reference the Assets that are moving, along with their new location. The new location can be in the form of a geometry and/or a reference to one or more location Assets.

It is possible to find an Asset's location at any point in time by querying its movement Logs.

Generally a movement Log is only included if it is "done", although it is also possible to find "pending" movement Logs in the future to find an Asset's projected future location.

Locations

Assets can be designated as locations. This allows other Assets to be moved to them.

Typically, fixed Assets will also be designated as locations. However, movable Assets can also be locations. Consider a tractor (Equipment Asset) with multiple attachments (more Equipment Assets). It is possible to record that an attachment is connected to the tractor, and therefore its location is derived from the tractor's location.

Fixed location Assets can designate parent Assets to create a hierarchical organization.

Logic

The logic for determining an Asset's geometry is as follows:

• Is the Asset fixed?
  • Yes: Does it have an intrinsic geometry?
    • Yes: intrinsic geometry
    • No: no geometry
  • No: Does it have a movement Log?
    • Yes: Does the movement Log have geometry?
      • Yes: movement Log geometry
      • No: Does the movement Log reference a location Asset?
        • Yes: (recurse to determine location Asset's geometry)
        • No: no geometry
    • No: no geometry

Geometry

When a Log is saved without a geometry, and it references locations that have geometries, the combined geometries of the referenced locations will be copied to the Log. Assets referenced in the Location relationship are given first priority. If none are found, then Assets referenced in the Log's Asset relationship will be used. In the latter case, only Assets that are explicitly designated as locations will be included, and geometry will not be copied if the Log is a movement (otherwise it would be impossible to clear the geometry of a non-fixed location Asset via movement Logs).