## Geometry Type Designators

Listed below are the geometry type designators used to describe the exact nature of a Feature's spatial component(s).

Designator | Value Type | Description |
---|---|---|

`GEOMETRY` |
`object` |
GeoJSON `Geometry` object |

`POINT` |
`GEOMETRY` |
GeoJSON `Point` geometry |

`MULTI-POINT` |
`GEOMETRY` |
GeoJSON `MultiPoint` geometry |

`LINE-STRING` |
`GEOMETRY` |
GeoJSON `LineString` geometry |

`MULTI-LINE-STRING` |
`GEOMETRY` |
GeoJSON `MultiLineString` geometry |

`POLYGON` |
`GEOMETRY` |
GeoJSON `Polygon` geometry |

`MULTI-POLYGON` |
`GEOMETRY` |
GeoJSON `MultiPolygon` geometry |

`POLYGONAL` |
`POLYGON` or `MULTI-POLYGON` |
Option of `POLYGON` or `MULTI-POLYGON` geometry |

`LINEAL` |
`LINE-STRING` or `MULTI-LINE-STRING` |
Option of `LINE-STRING` or `MULTI-LINE-STRING` geometry |

`DISPLAY-POINT` |
`POINT` |
`POINT` based representation of Polygonal or Lineal Features |

### Display-point

A Display Point represents a curated, Point-based representation of a non-puntal Feature.

- Display Points are members of a Feature's
`"property"`

object - Display Points
**MUST**be captured as GeoJSON Point objects - Display Points
**MUST**be within the geometry of the Feature that possesses it - Display Points
**SHOULD**be positioned in a location where map label "collision" is least expected

### Horizontal Positional Accuracy

Features that explicitly reference this rule-set **MUST** be within +/- 5 meters of their actual ground location when tested using an independent source of higher accuracy.

- The independent source of higher accuracy shall be of the highest accuracy feasible and practicable to evaluate the accuracy of the feature

### Polygon Winding Order

RFC 7946, Section 3.1.6 states the following when describing Polygons and the winding order of linear rings:

"A linear ring MUST follow the right-hand rule with respect to the area it bounds, i.e., exterior rings are counterclockwise, and holes are clockwise." Note: The [GJ2008] specification did not discuss linear ring winding order. For backwards compatibility, parsers SHOULD NOT reject Polygons that do not follow the right-hand rule.

As a result, Features with polygonal geometries that do not follow the right-hand rule will **NOT** be rejected at this time, but **MAY** produce informative warnings if and when observed.

### Precision

Precision **SHOULD** be at least seven (7) decimal places.

- Seven (7) decimal places is equivalent to a planar distance of ~11mm which is tolerable for mapping and surveying purposes