LGIM GeopoliticalArea vs Landbase

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12-28-2016 12:33 PM
DavidHaines
Occasional Contributor

In the Local Government Information Model (LGIM) what is the difference between the GeopoliticalArea FC and the Landbase FC.

The description for GeopoliticalArea is "The geographic extent of a political governance area or civil area..." which certainly sounds like it should be used for something like a city boundary. Most of the attributes agree. However, the is an Effective Date, End Date, and Source Reference.  Again, for a city this would be perhaps the incorporation date, dissolved date (which is very rare), and a reference to the city charter? This seems an obscure need for city boundary. So perhaps this should be used for something more like annexations? That way you would know when what part of the city became a city and a link to the document that enabled it.

The description for Landbase is "A polygon that represents the extent of the cities land base and used to author multi-scale basemaps." This to sounds like the something like the city boundary, but perhaps with different levels of detail. But then why isn't there a field for describing at what scale the polygon should be used at?  Or instead of the actual boundary, it is to represent more of the urban or built-up area?

So what is the difference between GeopoliticalArea and Landbase? Where do annexations get tracked (I see LandUseCase/CaseType, but what was applied for, not what was actually approved)?

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RyanTucker2
New Contributor II

In our case, a small coastal city in California , we have a harbor with Moles which are not within our cities legal boundaries, but are within our jurisdiction through a joint trust with the state. My Landbase FC includes those harbor moles and the area within our legal city boundaries, and my GeopoliticalArea FC includes the area within our legal city boundaries and excludes the harbor moles. 

Hope that helps.

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