The Old Joel on Software Forum: Part 4 (of 5) - Geocoding and proximty search question

Geocoding and proximty search question

Has anyone had good or bad experiences using any of the geocoding services out there? I'm working on a project where we need to do proximity searches to find store centers nearest to customers (for the UK).

MS Mappoint, MapQuest, and WhereonEarth.com seem to be the big vendors with the best data. Their services will run between $10K to $100K per year depending on server setup.

But right now we only need UK data - and the postal code system in the UK seems to indicate it is relatively straightforward to figure this stuff out. The Royal Mail (royalmail.com) provides a datafile mapping the post codes to a geographic grid, but in a disclaimer it says that about 8% of their data (a few islands and most PO boxes) doesn't include the grid points!!

NathanJ
Thursday, March 4, 2004

I've worked a little with a geocoding software package and its dataset for the U.S called RouteMap IMS. It's from ESRI. I found it to be pretty good and quite flexible (more flexible than its marketing materials would have you think), though the API documentation was poor. What you are doing is the most common sort of application that uses this kind of package, so you wouldn't even need to use the API as there is prebuilt JSP and ASP code for such things. Other offerings will have similar turnkey stuff for that, too.
RouteMap is US$12k / server-year for use in publicly accessable products, US$6k / server-year for internally used products. It was the cheapest thing I could find with an API, but still too expensive for my project. What did you find at the $10k price point? I researched about fifteen different packages, let me know if you want my notes.

Since the UK has fewer people and fewer addresses I would think it ought to be cheaper... on the other hand the entire country has lots of irregular street numbers and complicated street patterns (compared to the US) so that probably evens things out.

Ethan Herdrick
Thursday, March 4, 2004

The link for RouteMap: http://www.esri.com/software/routemapims/

Ethan Herdrick
Thursday, March 4, 2004

There's also TeleAtlas, but I don't know much about them.

http://www.teleatlas.com/homepage.jsp

runtime
Thursday, March 4, 2004

I have worked for an ESRI Distributor for quite a while and knew most of their products (released by 2000). Most of them, even the simplest ones (like MapObjects and ArcView) would support some form of geocoding. The Internet Map Server product (called ArcIMS) also had some geocoding features. Some ESRI products would come with map data for the U.S. but I have never bothered to check what kind of data were provided and what was their quality. I would guess free == useless.
I have noticed you're using the term "proximity". Are you talking about shortest straight line connecting two points, or driving distance? Judging by your description of the problem driving distance would make more sense. If so, you will need geocoding + shortest route estimation. In this respect, the higher-end ESRI products like ArcInfo and ArcRoute (I think they changed the name of the latter one) would do a pretty decent job, while ArcView and especially MapObjects would be too slow to be used in practical situations. It took MapObjects 40 minutes to find the best route in a city of 1.2 million on Pentium III/500 with quite a lot of RAM (128 megs? do not remember right now).

Alexander Chalucov
Friday, March 5, 2004

I've done exactly this a couple of years ago. I even created a website with everything you need to know on it – never bothered publishing it though; too much effort, given that I had paying work instead.

There are about 2 dozen products that will provide geographic searching and range in price and quality from about £100 to £100k. These are listed on the Royal Mail website.

Almost all the products you can buy will be deficient in some respect; you have to buy the next "module" to get the functionality you want. Agree with Alexander; think about whether you want shortest route or distance. It won’t make much difference here (UK) though. Also think about whether you need a description of the route or a map (much more expensive)

MapPoint has the data you need, although I have no idea how easy the API is to use or what the licensing requirements are like.

There are 2 main Royal Mail products; the Postoffice Address File (PAF) and PostZone. The former provides full addresses, the latter maps post codes against geographic coordinates. These coords are Eastings and Northings, not long/lat. I found that radial searching was much easier with these anyway, so didn’t bother with long/lat conversions. PostZone is produced based on geo data from the Ordnance Survey. It is available in 100, 10 and 1 metre versions, providing different levels of accuracy.

Also bear in mind the postcodes are “delivery points” not addresses. Royal Mail can and does move them around.

Their estimate of 8% missing data is low; I found it was closer to 13%. You could probably write something to derive the data, based on nearby postcodes.

The solution I went for involved stitching together data from MapInfo, Paf, PostZone and ONS data (for Local Authority etc). All Uk postcodes were mapped to local community parishes as part of the data load. Radial etc searching done on the fly. You can see the results at www.thelocalchannel.co.uk although I left this project in Dec 2002 - they seem to have broken some of the searches since then.

Products worth looking at are MapInfo and QAS (qas.com)

Justin
Friday, March 5, 2004

Microsoft's Mappoint came in at $8K - that's close enough to 10K for me. And as others pointed out there are add-on modules and stuff so the price would go up based on needs.

Our proximity search will be straightline based and not driving. Driving distance would be nice though...

NathanJ
Friday, March 5, 2004