OpenStreetMap

New MapRoulette challenge: TIGER Mismatched Ways

Posted by mvexel on 7 October 2014 in English (English)

I know, I’ve written about TIGER before…Quite a few times. I’ve pointed out problems from time to time, but I have also attempted to come up with solutions, like the Battle Grid.

battlegrid

Today is another being-part-of-the-solution kind of day. We (a few colleages at Telenav were involved in this) took the output of the Battle Grid comparison we use to generate the Battle Grid cells, divided them into more and less severe cases based on the road class and amount of difference between TIGER and OSM, and created a MapRoulette challenge out of the more interesting cases. This will make it easier for anyone to help fix antiquated, bad TIGER data anywhere.

This is what a typical case would look like in MapRoulette:

mr-case

Loading this case in iD, it’s plain to see that this road is mis-aligned pretty badly:

case-in-id

Easy to fix! Just drag the nodes that make up the misaligned way to match the aerial image:

fixed

Non-errors

To point out these errors, we compare TIGER 2014 against OSM data. This gets us mostly good results, but it’s not perfect. In most cases where MapRoulette will point out a non-error, the TIGER data is still wrong. This is the case in Alaska more than anywhere else, it seems.

alaska TIGER is wrong here, even though it’s hard to see with the low resolution satellite imagery…

The number of non-errors is small enough to not be too annoying, I hope. If it is let me know, and I can see what more we can do to improve this challenge.

Not all at once

There are a lot of Mismatched Ways. A lot. Most of them, way more than 90%, are local and low speed roads, mapped to residential in OSM when TIGER was imported. Of course, these all need to be fixed eventually, but let’s focus on the more important roads first. Based on how it goes, I will gradually add more cases.

I look forward to hearing from you about this new challenge! I am pretty excited about it!

To the TIGER Mismatched Ways challenge!

Comment from Pieren on 8 October 2014 at 14:13

One question from a non-US contributor: what is recommended if we find a TIGER imported road in OSM which seems to not exist at all on imagery like this one:
http://www.openstreetmap.org/way/16481479

simply delete the way ? or change the tags to ‘disused:’ or ‘razed’ ?

Comment from mvexel on 8 October 2014 at 14:48

Pieren: I usually just delete these ways that don’t seem to exist. Before I do so, I look up and down the main road to see if the road should be moved rather than deleted. But especially the short ‘doodles’ sticking out form the main road that have no names, I mostly just delete.

Comment from Takuto on 10 October 2014 at 07:38

Eh! Trying to open link to challenge, then I get “Challenge done, select some other” message. Is it really already done?

Comment from mvexel on 10 October 2014 at 20:06

Takuto - Whoa, yes the first batch is done already! I didn’t expect it to happen this quickly. Let me get some more up (there’s lots more) - will post here when they are ready.

Comment from skorasaurus on 14 October 2014 at 20:43

wow, that was completed quickly! Looking forward to seeing the next batch!

Comment from SimonPoole on 16 October 2014 at 10:51

@pieren a bit late, but anyway: you do need to check a wider area around the location. One thing that is very common with TIGER is that the roads actually exist but are offset a km or so. Don’t think GPS, think jotting down the approximate position of a turn off on paper.

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