postcode to coords automation

gstenson · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

Chk out this link. While this does not allow multiple inputs its much better than the normal streetmap UI.

http://www.streetmap.co.uk/streetmap.dll?GridConvert

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

Have just submitted the remaining POIs for postcode searches in the North West, North East, Wales and the Midlands.

Am sure they will be on the PocketGPS POI page shortly.

gstenson · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

I will certainly try them out - thanks for your efforts!

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

Hi All

I've separated the Postcodes into a single file per postcode area e.g. NN, CW, DE etc. and then packaged them per region.

I've tested them and the search is not a limiting factor any longer. My personal oppintion is that if you are happy with a large number of POI files, the solution works well.

I now have postocodes for Anglia, London, South East, South Central, South West and Scotland and have sent these through to Pocket GPS. North West, North East, Wales and the Midlands to follow.

I'm sure Dave will tell us when these have been uploaded to the website.

Please try these out and tell me what you think.

Buffy Beagle · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

Hello, we would like to compile POI files for places in Germany for which we have 5 digit postcodes.

Does anyone know whether there is a facility similar to the Streetmap GridConvert page (which was mentioned earlier in this thread) that will convert German postcodes (PLZ codes) into latitude/longitude? ... or, even better, a data file containing this information that can be downloaded? Since there can be at most 100,000 5 digit codes, such a file need not be toooo big!

Thanks.

Hugh

Carlos · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

Yes I think you're right...I reckon it would be possible to search through say 250k postcodes if you had a decent indexing system (particularly when you consider the nature of the data), I guess the ov2 structure lacks this.

There are more streets in the country than postcodes, so whatever data structure they use for the town->street method works well enough, shame they can't do this with postcodes.

Dave · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

I think you've hit the nail on the head. TomTom OV2's really aren't meant to support this amount of data, the OV2's probably aren't optimised enough. Although, one thing you have to bear in mind no package does real postcode routing.

Take CoPilot for instance, the post code you type in will only go down to the first digital of the second part of the postcode, and still it requires a street name. The way CoPilot does this is to use the postcode to take you to the city but no closer than that, you then have to enter a street name in to make it worth while. It's just shorter than typing the city name really. I think if any company were to include this in their geodata, it would take a while to search through these on a Pocket PC, there's probably no way to avoid this (hence why full postcode support isn't covered under any application).

Carlos · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

Hi all

New to this forum, just set up my Ipaq/Tom tom system.

I have access to all uk postcodes and locations at work. For copyright reasons I can't release them.

Anyway my point is that large numbers of pois do not work well in TomTom - it takes ages (minutes) to search out a postcode. I have created several postcode ov2 files similar to the structure that zoyah suggests, each with 100k - 250k postcodes. It just isn't viable...

Unless you want to sit for several minutes typing the postcode in, as it goes away and does a refine search after each keypress.

I'm disappointed as full postcode search is the only major feature lacking in TomTom imo, I thought I could do it with pois but it's not been successful.

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

I've been thinking about this and it does make sence to have a single file per postcode area (good idea trafcam). To make it easier to manage, they can be distributed by regional area i.e.

Scotland

Wales

N.East

N.West

Midlands

Anglia

S.West

S.Central

S.East

London

The only issue would then be the number of POI files. What is the limit, I seem to recall reading somewhere that there is one?

PS: Have an additional 340,000 postcodes.

trafcam · Regular Visitor Joined: 30/10/2002 11:57:49 Posts: 155

124, in fact. I was just thinking that if you have to split things down at all, it's a logical way of doing it as you already know which POI file to use if you're looking for a particular postcode. Also users could have the option (if they're short of space) of only loading postcode areas that are relevant to them.

You might also want to check the copyright position on this, as I know that the Royal Mail are very protective over uses of the Postcode system like this.

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

trafcam...

possible, but there are 159 of them for the UK.

trafcam · Regular Visitor Joined: 30/10/2002 11:57:49 Posts: 155

Only other option is making the POI files smaller, i.e. less data per POI file = more POI files. Not sure what the best way would be to segment the UK though

What about a single file per postcode area? NN, CW, DE etc.

Dave · Posted: Sun Sep 14, 2003 8:04 am Post subject: postcode to coords automation

Guys, I haven't got time to update the POI page until tonight, but I've uploaded them and you can grab them from here in the mean time...

Post Code Search Central London 1.6mb

Postcode_Search-Central_London_2m_radius 577kb

Postcode_Search-Central_London_5m_radius 1.1mb

Postcode_Search-Surrey 298kb

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

I have sent the POI file through to Dave for the Greater London area. I'm not sure when/if it will be posted on the site. It is quite large (5.4meg ov2 file with 218,000 postcodes) but it works. Sadly the search seems to take 3 min for a list this large.

I'd be happy to send it to to anyone else who wants it.

The Surrey search will follow in a couple of days.

I've been thinking about the speed issue and the biggest problem is TTN2's built in "sounds like" search facility. Has anyone played with the API who may be able to put together a simple add-in that will read from the POI file and just make exact matches? Then all that would remain would be to feed the lat and long back into TTN. Any thoughs on this anyone? Can anyone help?

Only other option is making the POI files smaller, i.e. less data per POI file = more POI files. Not sure what the best way would be to segment the UK though.

zoyah · Occasional Visitor Joined: 20/05/2003 21:31:20 Posts: 17

The process of getting the postcodes is taking some time, so getting through all 1.7 mil is not going to be trivial. I have decided to work on Greater London (80% complete) first and currently have 150,000 postcodes. I'll post the .ov2 and .asc file when done and then move to another county (Surrey first).

Regarding searching through the POI file. I've done a test with 120,000 points and it gets to be sluggish because of the "sounds like" search in TTN. It might also be because I've stored all the maps on my SanDisk SD card. Anyone know if TTN will search another directory for POIs in addition to the maps directory? There must be a way to specify more than 1 location for the maps.

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