Well-Known Binary (OGC)
Open BetaWKB (Well-Known Binary) is the binary representation of vector geometry from the OGC Simple Features standard (1999), the foundation of almost every GIS database: each geometry inside PostGIS, MySQL Spatial or GeoPackage is WKB. The format is several times more compact than textual WKT because coordinates are packed into doubles without ASCII. Our exporter writes the geometries of the selected OSM layers into a .wkb file: every object is standard OGC WKB, but the file is a container — an 8-byte header (a WKB marker plus the number of objects), then geometries with a length prefix, while the coordinate system lies in a companion .prj file. Honestly: to parse the file you have to read the header and the lengths — this is not a single "bare" blob for a direct ST_GeomFromWKB. Attributes are not preserved, and all the selected layers are merged into one stream of geometries (up to 500,000 objects).
Põhiomadused
Vormingu WKB kohta
WKB is the binary encoding of geometry from the OGC Simple Features standard: byte order, a shape type code and coordinates as double-precision numbers. Inside PostGIS, GeoPackage and SpatiaLite geometry is stored exactly like this, which is why WKB is read and written by every spatial library — Shapely, GEOS, JTS, GDAL.
This export is taken by people writing their own pipeline: parsing without going through text, loading into a database, testing their own implementation of the standard, compact transfer of geometry between services.
You need to know how the file is arranged in advance. This is not one "bare" geometry but a container: eight bytes of header (a WKB marker and the number of objects), then geometries one after another, each preceded by its length. The geometries themselves are standard OGC WKB and can be fed into ST_GeomFromWKB one by one once the container is parsed. The coordinate system lies in a neighboring .prj file in text form.
The limits: OpenStreetMap attributes are not preserved — geometry only, and all the selected layers are merged into a single stream with no separation. The ceiling is 500,000 geometries. If you need names, tags and layers, take GeoPackage, FlatGeobuf or GeoJSON.
Milline programm avab WKB-faile
Järgmised programmid ja rakendused suudavad avada, redigeerida ning töödelda OSM2CDR-ist eksporditud Well-Known Binary (OGC) (.wkb) faile:
Format specifications
- Open standard
- 2D only
- Lossless (no quality loss)
- No attributes
- Output: 1 file
- An OGC WKB container: an 8-byte header then length-prefixed per-feature geometries, with the CRS in a companion .prj; not a single bare blob, multiple layers as a ZIP.
Kes kasutab WKB-kaarte
Kuidas eksportida vormingusse WKB
Kuidas pärast eksporti avada
- Python — read the 8 bytes of the header, then loop: 4 bytes of length and that many bytes of geometry, each through shapely.wkb.loads(); you end up with an ordinary list of Shapely objects.
- PostGIS — load the geometries one at a time: ST_GeomFromWKB(%s, 4326) accepts a chunk unpacked from the container as is.
- The .prj file — do not lose it when moving things around: it records the coordinate system, and without it the receiving side will be guessing.
- GDAL and QGIS — they will not open this container as a ready layer; if you need a layer out of the box, take GeoPackage or FlatGeobuf.
- Checking — compare the number of objects from the header with how many geometries you parsed: a mismatch means the file was not read to the end.
Populaarsed kaardid vormingus WKB
Hangi kaardiekspordid vormingus Well-Known Binary (OGC)
Laadi alla professionaalsed WKB-kaardid OpenStreetMapi andmetest. Kohene genereerimine, mis tahes ala.