The need for addresses

One of the things that often comes up in discussions about OpenStreetMap is poor address coverage in some places.

Rightly or wrongly, to many people a map is now no longer just a 2D representation of our environment. Searching and navigation/routing, despite being separate services, are viewed as part of a map, and almost as important as the visual map itself. We need good address coverage to improve geocoding.

Adding addresses really improves the map, and that’s what keeps me going with it. When I explained what I was doing to one person who approached me, he said “that’s a good idea mate, Google Maps shows my house all the way down the end of the road”. I also saw a food delivery driver pull up outside a house and ask “is it called Gate House?”. (On OpenStreetMap it is ☺)

Chancel Way or Chancel Park?

Recently I collected addresses on Chancel Way in Charlton Kings, Cheltenham. When adding them, I noticed something that didn’t seem right.

The road was split into Chancel Way and Chancel Park. At first glance, this seems fine. Having a common prefix like this is common in UK residential street names. (For example, Croft Road, Croft Gardens, Croft Drive, and Croft Avenue are nearby.)

The house numbering suggested that Chancel Way and Chancel Park were actually a single street. Following the street west, the first number on the left (south) side of Chancel Park was 19, and the next number was 21. This fits with the final odd number on Chancel Way (17). Even numbers on the right (north) side of the street match too.

More research

There are no results for Chancel Park on the Royal Mail postcode finder, yet it appears on Apple Maps (via DuckDuckGo):

It also appears on TomTom (no surprise as Apple uses TomTom data in places):

The mysterious Chancel Park also appears on Bing Maps:

… and HERE.

Much as it pains me to admit, Chancel Park is not shown on Google Maps; the whole street is shown as Chancel Way.

I even walked back and checked for any sign of Chancel Park on the ground. I found none. Chancel Park does not exist.

How did the mistake happen?

Chancel Park was added in changeset 7794450 on 2011-04-07, over nine years ago. The source:name tag was set to OS_OpenData_Locator. To my surprise, OS OpenData Street View shows Chancel Park:

OS MasterMap correctly shows the whole road as Chancel Way though.

It’s likely that TomTom (who supplies Apple) and HERE trusted OS OpenData Street View, and ended up with the mistake that way.

Closing thoughts

I discovered this mistake (which I’ve now fixed) through address mapping. If I’d just looked at the area on OpenStreetMap, the problem wouldn’t be obvious. Even a normal ground survey wouldn’t pick this up unless you were specifically comparing streets on the map with streets on the ground.

While out collecting addresses I’ve also found other useful things to map including:

• Tiny missing paths and shortcuts (like this one)
• Missing turn restrictions
• Cycle lanes
• …

Looking at other maps for preparing this entry has made me realise how plain they are and how little information they convey compared to OpenStreetMap. Apple Maps has no buildings in this area, and doesn’t show River Chelt either.

Most striking though is how little information other maps show for walking and cycling. There’s a path linking St Judes Walk to a walking and cycle path to the west. This is a pleasant route through Charlton Park and Cox’s Meadow, and then on to the hospital, lido, Sandford Park, and the town centre. This level of detail is a huge advantage of OpenStreetMap.