GeoCSV: Unterschied zwischen den Versionen

Version vom 30. April 2015, 15:15 Uhr

Specification of a 'modern' CSV with a geometry extension of either two easting/northing colums or one WKT column!

CSV file format specification

• Encoding is UTF-8 by default.
• First row contains attribute names separated by a => delimiter.
• Following rows are contains values separated by a => delimiter.
• Delimiter is semicolon (;) by default.
• Strings are enclosed by parantheses, to allow delimiters inside (e.g. "string").
• Data types (if supported from source or target system): See CSVT file format specification.
• Coordinate system is WGS84 (EPSG:4326) by default.

GeoCSV file format specification

GeoCSV is based on CSV. The extension comes with two variants: Options easting/northing and Options WKT.

Options "easting/northing" (similar to x/y in mathematics):

• Geometry Point type as two neighboring columns of type Float: one containing the easting coordinate, and one containing northing coordinate separated by the common delimiter.
• Example for the two easting/northing columnts "47.2274;8.8249".
• This option supports only Points.

Options WKT:

• It' one single column of type String containing a constructor, like for example: "POINT (47.2274,8.8249)".
• This option supports Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon.
• WKT ("Well Known Text") is originally defined by the Open Geospatial Consortium (OGC) and described in their Simple Feature Access specification (also ISO SQL/MM). See e.g. http://en.wikipedia.org/wiki/Well-known_text

Common restrictions:

• All values within one table are in the same coordinate reference system (CRS).
• There is only one geometry column allowed.

CSVT file format specification

Field/column types (if supported from source or target system):

• Integer
• Real
• String
• Date ("YYYY-MM-DD"), Time ("HH:MM:SS+nn") and DateTime (YYYY-MM-DD HH:MM:SS+nn)

See also http://www.gdal.org/drv_csv.html section with .csvt extension.