How to Write, Convert, and Read WKB Data with JTS in Java

WKB Overview

WKB (Well‑Known Binary) encodes geometric objects as a binary stream using a 1‑byte unsigned integer, a 4‑byte unsigned integer, and 8‑byte double‑precision numbers (IEEE 754). Because it is binary, WKB offers higher transmission and storage efficiency than the text‑based WKT format.

Storing WKB in Databases

Both MySQL and PostgreSQL store geometry column values in WKB format. For example, the MySQL query SELECT hex(st_asbinary(st_geomfromtext('POINT(1 2)'))) returns the hexadecimal representation of a point.

JTS API for WKB

The JTS library provides classes for WKB operations. The following diagram shows the relevant API (image omitted for brevity).

Writing WKB and Converting to Hex

GeometryFactory geometryFactory = new GeometryFactory();
Point point1 = geometryFactory.createPoint(new Coordinate(112.11, 2225.21));
WKBWriter wkbWriter = new WKBWriter();
byte[] write = wkbWriter.write(point1);
String hex = WKBWriter.toHex(write);
System.out.println(hex); // 0000000001405C070A3D70A3D740A1626B851EB852

Reading WKB Back to Geometry

WKBReader wkbReader = new WKBReader();
Geometry geometry = null;
try {
    geometry = wkbReader.read(write);
} catch (ParseException e) {
    e.printStackTrace();
}
System.out.println(geometry.toText()); // POINT (112.11 2225.21)

Complete Example

// Write WKB
GeometryFactory geometryFactory = new GeometryFactory();
Point point1 = geometryFactory.createPoint(new Coordinate(112.11, 2225.21));
WKBWriter wkbWriter = new WKBWriter();
byte[] write = wkbWriter.write(point1);
String hex = WKBWriter.toHex(write);
System.out.println(hex); // 0000000001405C070A3D70A3D740A1626B851EB852

// Read WKB
WKBReader wkbReader = new WKBReader();
Geometry geometry = null;
try {
    geometry = wkbReader.read(write);
} catch (ParseException e) {
    e.printStackTrace();
}
System.out.println(geometry.toText()); // POINT (112.11 2225.21)