[GIS] wkb/wkt according to OGC

pointrepresentationwell-known-binarywell-known-text

how can i store my coordinates in wkb.. i want to know its implementation of wkb and wkt in db .. any one can please guide me.

Best Answer

http://dev.mysql.com/doc/refman/5.0/en/gis-wkb-format.html

For example, a WKB value that corresponds to POINT(1 1) consists of this sequence of 21 bytes (each represented here by two hex digits):

0101000000000000000000F03F000000000000F03F

The sequence may be broken down into these components:

Byte order : 01
WKB type   : 01000000
X          : 000000000000F03F
Y          : 000000000000F03F

Related Solutions

Converting WKB to WKT – Complete Guide

If you want to use PostGIS to do the conversion, you can choose from the following functions:

bytea WKB = ST_AsBinary(geometry);
text WKT = ST_AsText(geometry);
geometry = ST_GeomFromWKB(bytea WKB, SRID);
geometry = ST_GeometryFromText(text WKT, SRID);

More: http://postgis.net/docs/manual-1.5/ch04.html#OpenGISWKBWKT

[GIS] WKB to WKT JavaScript function

It looks like a new and better supported JS WKB parsing library has since appeared.

https://github.com/cschwarz/wkx

I've been able to use it to convert WKB directly from postgres into JS objects that can be mapped in the browser. You'll need to include https://github.com/cschwarz/wkx/blob/master/dist/wkx.js in your webpage for this to work.

// Required imports (works in browser, too)
var wkx = require('wkx');
var buffer = require('buffer');

// Sample data to convert
var wkbLonlat = '010100000072675909D36C52C0E151BB43B05E4440';

// Split WKB into array of integers (necessary to turn it into buffer)
var hexAry = wkbLonlat.match(/.{2}/g);
var intAry = [];
for (var i in hexAry) {
  intAry.push(parseInt(hexAry[i], 16));
}

// Generate the buffer
var buf = new buffer.Buffer(intAry);

// Parse buffer into geometric object
var geom = wkx.Geometry.parse(buf);

// Should log '-73.700380647'
console.log(geom.x)

// Should log '40.739754168'
console.log(geom.y)

Best Answer

Related Solutions

Converting WKB to WKT – Complete Guide

[GIS] WKB to WKT JavaScript function

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