Process the OS code-point-open data and generate JSON containing Lat/Lon coordinates for every UK postcode. An example use of MadeByPi/cartography-coordinate-tools

UKPostCodesToLatLon.hx

package ;

// https://github.com/MadeByPi/cartography-coordinate-tools
import cartography.CoordTransform;
import cartography.LatLon;
import cartography.OSGridRef;

import neko.Lib;
import sys.io.File;
import sys.FileSystem;

using StringTools;

/**
 * @author Mike Almond - https://github.com/mikedotalmond - https://github.com/MadeByPi
 * 
 * Process the OS code-point-open data and generate JSON containing Lat/Lon coordinates for every UK postcode.
 * OS data provides positional data for each point in the OS Grid format (Easting,Northing), but lat-lon cooridnates are generally more useful in mapping applications.
 * 
 * Uses cartography-tools - https://github.com/MadeByPi/cartography-coordinate-tools
 * With data from - http://www.ordnancesurvey.co.uk/business-and-government/products/code-point-open.html
 */

class Main {
	
	static function main() {

		/**
		 * You'll need to download + extract the open dataset of all UK postcode-points -- a zip containing CSV files for regions
		 * http://www.ordnancesurvey.co.uk/business-and-government/products/code-point-open.html
		 */ 
		var dataPath 	= 'codepoints_gb/Data/CSV/';
		var files 		= FileSystem.readDirectory(dataPath);
		
		trace('Processing ${files.length} codepoint csv files...');
		
		var outpath = 'processed';
		if (!FileSystem.exists(outpath)) FileSystem.createDirectory(outpath);
		
		for (file in files) {
			if (file.toLowerCase().endsWith('csv')) {
				var fileName = file.substr(0, file.length - 4);
				var output = processFile('$dataPath/$file');
				
				Lib.println('Saving as JSON to $outpath/$fileName.json');
				File.saveContent('$outpath/$fileName.json', output);
			}
		}
	}
	
	
	static function processFile(file:String):String {
		
		var fIn 			= File.read(file, false);
		var lineNum 		= 0;
		
		/** CSV headers...
		 * PC,PQ,EA,NO,CY,RH,LH,CC,DC,WC
		 * Postcode, Positional_quality_indicator, Eastings, Northings, Country_code, NHS_regional_HA_code, NHS_HA_code, Admin_county_code, Admin_district_code, Admin_ward_code
		 */
		
		var out:StringBuf = new StringBuf();
		out.add('[');
		
		try {
			while ( true ) {
				
				var fields  = fIn.readLine().split(",");
				
				var gridref	= new OSGridRef(Std.parseInt(fields[2]), Std.parseInt(fields[3]));
				var latlon 	= OSGridRef.osGridToLatLong(gridref);
				
				latlon 		= CoordTransform.convertOSGB36toWGS84(latlon);
				
				var pcode 	= fields[0].substr(1,7).toUpperCase(); // remove "" around the post code
				
				if (lineNum > 0) out.add(',');
				out.add('{"c":"${pcode}","la":${latlon.lat},"lo":${latlon.lon}}');
				
				lineNum++;			
			}
			
		} catch ( ex:haxe.io.Eof ) { }
		
		fIn.close();
		
		Lib.println('$file - processed $lineNum postcodes');
		
		out.add(']');
		
		return out.toString();
	}
}