EWKT — PostGIS Extended WKT With an SRID Prefix
PostGIS's extended WKT, which prefixes the geometry with `SRID=4326;`. It is not part of the OGC standard, so a strict WKT parser rejects the whole string — while a PostGIS-aware one gets the coordinate system for free.
SRID=4326;POLYGON ((-12.49 47.06, -12.474 47.06, -12.474 47.069, -12.49 47.069, -12.49 47.06))
Specifications
- Format
- PostGIS EWKT
- Crs
- WGS 84 (EPSG:4326)
- Coordinate Order
- longitude latitude
- Encoding
- ASCII
- Line Endings
- LF
- Coordinate Precision
- 6
- Srid Prefix
- SRID=4326;
- Geometry Type
- POLYGON
- Standard
- PostGIS extension, not OGC WKT
- Valid
- true
Testing contract
Expected to pass- Scenario
- Parse the value with a strict OGC WKT parser and then with an EWKT-aware one.
- Expected result
- The strict parser rejects the SRID prefix; the EWKT-aware parser returns the polygon tagged with EPSG:4326.
What is a .wkt file?
WKT (Well-Known Text) is the OGC's human-readable encoding for geometry and for coordinate reference systems. Geometry WKT spells out a type and its coordinates — POINT, LINESTRING, POLYGON, and their MULTI and GEOMETRYCOLLECTION forms — while CRS WKT nests PROJCS, GEOGCS, DATUM, and PARAMETER clauses. Its binary counterpart, WKB, encodes the same geometry model compactly.
How to use this file
Use an example .wkt file to test geometry parsers and CRS handling, exercising polygons with interior rings, empty geometries, coordinate precision, and the difference between WKT geometry and WKT coordinate-system definitions.
How to use this file for testing
“EWKT — PostGIS Extended WKT With an SRID Prefix” is a deterministic Novus Examples fixture for Geospatial, Serialization testing, Conversion testing. GeoJSON, GPX, and KML files with points, lines, polygons, and tracks — for testing map tools, route parsers, and geo importers.
Documented properties for this file: ASCII · LF · PostGIS EWKT. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Geospatial fixtures publish one invented territory across formats, with the coordinate reference system and feature counts documented in specs. Convert or reproject and diff against the twin in the same group; edge-case geometries state exactly which assumption they are built to break.
Related files
- txtEWKB — PostGIS Hex With an Embedded SRIDPostGIS EWKB, where the SRID is carried by OR-ing 0x20000000 into the geometry-type word and appending the code. A strict OGC WKB reader sees type 0x20000001 instead of 1 and either fails or, worse, reports an unknown geometry type.
- binWKB — Raw Little-Endian PointTwenty-one raw bytes: a byte-order flag, a little-endian geometry-type code of 1, and two float64 ordinates. This is the wire format PostGIS, GeoPackage and most spatial drivers actually move geometry in.
- wktWKT — GEOMETRYCOLLECTIONA single WKT value for a point, a line and a polygon in one value. WKT nests with bare parentheses and no type tags on the inner parts, so the number and depth of brackets is the only thing that distinguishes a polygon ring from a multipolygon member — which is where hand-written parsers go wrong.
- wktWKT — LINESTRINGA single WKT value for the four-vertex Coast Road. WKT nests with bare parentheses and no type tags on the inner parts, so the number and depth of brackets is the only thing that distinguishes a polygon ring from a multipolygon member — which is where hand-written parsers go wrong.
- wktWKT — MULTIPOLYGONA single WKT value for all three parcels in one geometry. WKT nests with bare parentheses and no type tags on the inner parts, so the number and depth of brackets is the only thing that distinguishes a polygon ring from a multipolygon member — which is where hand-written parsers go wrong.
- wktWKT — POINTA single WKT value for the Kestrel Bay town centre. WKT nests with bare parentheses and no type tags on the inner parts, so the number and depth of brackets is the only thing that distinguishes a polygon ring from a multipolygon member — which is where hand-written parsers go wrong.
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