Distortion (GRID)

Element Description

The group contains grid distortion sub-fields Description and Percent.

All grid projections result in some distortion of the relationships between features on the sphere when they are projected onto a flat surface.  These distortions include:

• • the direction between a feature and surrounding features
  • the distance between a feature and surrounding features
  • the shape of any feature
  • the size of any feature

The only ‘projection’ which has all features with no distortion is a globe.

Reference: Intergovernmental Committee on Surveying & Mapping, (2020), Fundamentals of Mapping, (DA2020),https://www.icsm.gov.au/education/fundamentals-mapping/overview-fundamentals-mapping

Best Practices

The group is optional and it is highly recommended giving  the user of the grid what distortion to expect within the grid and the percent of the distortion of the grid.

Example:

"Distortion": {
   "Description": "Distortion around the grid edge",
   "Percent": 31
}

Element Specification

Distortion is optional in the GRID (Cardinality: 1).

Metadata Validation

All records undergo schema and business rule validation before entering the system. 

• This element is not required.
• Both sub-elements Description and Percent should be used together.