Define positions for areas of a spatial coding system.
Arguments
- processData
AreaPosition
as returned from this function.- DefinitionMethod
'ResourceFile' or 'StratumPolygon', see details.
- FileName
path to resource file
- StratumPolygon
StratumPolygon
to extract area positions from.- UseProcessData
If TRUE, bypasses execution of function and returns existing 'processData'
Details
Defines an association between area codes and positions that represent that area code.
For example an area code could be associated with the centre of mass of the area, or
some other point within the area. This may be useful for providing approximate
coordinates when locations are identified by area codes. The soruce of the
area-position association may be a table or a appropriately formatted
polygon-definition (StratumPolygon
).
For DefinitionMethod 'ResourceFile': Definitions are read from a tab separated, UTF-8 encoded file with headers. Columns defined as:
- Column 1: 'Area'
Area code (key)
- Column 2: 'Location'
optional subdivision of area. If provided, positions for missing locations should be encoded as well.
- Column 3: 'Latitude'
WGS84 Latitude, decimal degrees
- Column 4: 'Longitude'
WGS84 Longitude, decimal degrees
For DefinitionMethod 'StratumPolygon':
Definitions are extracted from a StratumPolygon
:
'Area' in AreaPosition
is derived from the column 'StratumName' in StratumPolygon
.
'Location' in AreaPosition
is encoded as missing.
'Latitude' and 'Longitude' in AreaPosition
are the coordinates set for each polygon in StratumPolygon
.
See also
SetAreaPositionsBiotic
and AddAreaPositionStoxLanding
for adding positions to data.