Saturday, 9 April 2011

Dreadful weather for armchair mapping

"Completeness" is a bit of a moving target when it comes to Open Street Map, but I don't suppose that I'm the only person who wants to see some sort of completeness in the content that matters to me. At the moment what that means in practice is that I would like to see an end to the coloured splodges that show up on the ITO analysis of my local area.

Like others, I've been steadily nibbling away at the missing roads, and the analysis is slowly turning monochrome, but unlike the most organised parts of the country, around here there is still plenty to do.

Because I'm keen to clear up the discrepancies there's quite a strong temptation to take the easy way out, and fix things without getting out there and taking a look. In some cases that seems to be the sensible approach. There doesn't seem much point in taking a round trip of a few miles to check that it's OK to change a name from "Abbreviation Rd" to "Abbreviation Road". Or to make sure that the right name is "Spelling Avenue", not "Sppelling Avenue".

On the other hand, without taking a look it would be easy to miss some of the genuine inconsistencies between the OS data, and what can be found on the ground. So I try to resist the temptation to do too much from the armchair. I try to keep a sensible balance between fixing things the quick and easy way when the reality of the situation is pretty obvious; or going to take a look myself when there is some doubt.

This morning was a lovely day. As a result the balance swung strongly in favour of getting the bike out and riding out to take a look around. The area I decided to cover was some suburban housing to the west of Windsor. It's not the most interesting destination, but there were quite a lot of coloured splodges in a small area that lies just off one of the routes that I regularly take purely for nice ride. On a loop of about 20 miles I managed to fix about a dozen road names, as well as enjoying a very pleasant ride out there and back.

Most (if not all) of the fixes could probably have been done easily without a visit - but what a waste of a fine day that would have been.

I'm still not sure what to do about discrepancies that are difficult to check - even with a visit. A number of those are either a country lane for which the OS has a name, but there doesn't seem to be any name displayed in situ. Or they occur where a road name changes, but it isn't clear exactly where.

I could assume that the OS knows what they are doing, and that the original tagging was wrong - and change the name accordingly. Or I could assume that the original tagging was based on local knowledge, and that the OS has got it wrong, and tag to suppress the error report. I suppose somebody will have a definitive answer, and I could try to research it - but that seems a bit over the top for short sections of insignificant roads. At the moment I am leaving cases like these for someone else to sort out.

So, someone else, whoever you are, the weather outside is lovely, and it's the perfect time to pull your finger out, and fix some of the stuff that I'm leaving. Until you do 100% "completeness" is going to be unachievable.

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