The MGCP model contains very precise specifications for feature extraction. The LandCover area feature classes are used as the base for all land areas, and only certain feature classes can be extracted as features on top of it. The feature class subtypes that can be used to represent other feature types either on or adjacent to land do not always represent all the subtypes available in a feature class.
The model contains very specific guidelines for the units of measurement that must be used when working with an extent. For example, each area is a cell one degree by one degree in size, and the LandCover area feature must cover the entire area without any gaps.
The LandCover extension allows you to add areas that penetrate the LandCover, validate the cell, and correct any errors found. It is composed of the following three tools:
- MGCP LandCover Extension—Allows you to modify LandCover areas using specific feature classes when it is enabled.
- MGCP LandCover Validation—Validates the LandCover feature within a cell feature during a Reviewer session and writes any errors found to the Reviewer table. Information written to the table consists of gaps found in the LandCover area contained within a cell.
- MGCP LandCover Create Polygons—The closed polyline features that have been recorded in the Reviewer table can be converted to polygons based on the target layer selected.
Cell validation
When the LandCover area within a cell is validated, a feature class is created so gaps in the LandCover can be represented in the map. The gaps are captured as line features and can include holes within a ground feature that is inside the cell.
Since the MGCP specification does not allow gaps within the LandCover area, these gaps must be filled using a feature class that is permissible to use as LandCover area.
LandCover area subtypes
The feature class subtypes that can be used as LandCover area features are as follows:
| Feature class | Subtype(s) |
|---|---|
BuiltupA | Built-Up Area |
CoastA | Tidal Water |
CropA | Rice Field |
CropA | Crop Land |
ExtractA |
|
FirebrkA | Cleared Way |
GrassA |
|
GroundA | Soil Surface Region |
LakeresA |
|
Landfrm1A |
|
Landfrm2A | Moraine |
LandIceA |
|
OasisA | Oasis |
SwampA |
|
TreesA | Wood |
TundraA | Tundra |
VoidA | Void Collection |
WatrcrsA |
|