OpenStreetMap

AlaskaDave has commented on the following diary entries

Post When Comment
WikiProject Emergency Cleanup 6 months ago

I'm not sure how much I'll be able to contribute to the discussion but I must say, I love the banner!

Thailand Mapping + London Mapping TONIGHT 8 months ago

Hi Harry,

AlaskaDave here. I just happened to catch your post and enjoyed reading your observations about the state of OSM mapping in Chiang Mai. Actually, most of the folks on that OSM heat map live here or spend a lot of time here and love mapping. Thailand is, as you surmise, pretty well mapped in spots and in other places not so well. Chiang Mai is a popular place for expats. Johnny and Tom live here full time, Stephan visits often, and is vying to come here more or less permanently if he can arrange a telecommuting situation at his real job, and I share time between here and Alaska. There are a few Thais working Chiang Mai too but the foreigners, farangs, are much more active.

I'm about to leave Thailand for the hot months. I'll go back to Alaska, a huge state with very small population, and few OSM mappers. It's vast and mostly unmapped. Most of the main roads are present but not much geography. It's an immense project that I began working on last year and that I will work on for many months to come. Rivers, streams, islands, peaks, glaciers, trails — lots of work.

I don't spend much time in the south of Thailand where the beaches are but I'll take a look at those problem areas you mentioned. Did you happen to leave Notes on the map near the problems?

At the moment, I am almost ready to leave for the airport but I'll check the above links when I have more time.

Best, Dave

The Overpass Query Wizard about 1 year ago

This is an awesome tool! Thank you.

I have used Overpass Turbo in the past and did find constructing queries to be both tedious and irksome. This tool makes it SO MUCH EASIER.

Excellent!

Mapping in Thailand about 1 year ago

Wow, your reservoir makes mine look tiny! Good job.

With OSM Inspector I looked at the geometry of the Kiew Ko Ma Reservoir and it all checked out with the exception of the two islands which had the error message "inner_in_inner". I changed their roles to outer and will wait to see how that checks out. At some point I will work up enough courage to try adding the two halves of the reservoir multipolygon together but using two distinct way segments for its outline in order to get around the 2,000 node limit. Thanks for bringing OSM Inspector to my attention. I have used it before but not enough to remember to employ it in diagnosing this problem.

Yes, I have read the documentation on multipolygons but it is not terribly helpful. The relation editor is another very opaque tool, difficult to use and not very user friendly. While there is much to like about JOSM, IMO it's help facility is sadly lacking. The Search tool is another I would take issue with but then, it is still vastly better than nothing at all.

You say "You can have multipolygons within multipolygons but you should try to avoid them if possible". Well, if that's the case, then how would you map a reservoir inside a pre-existing wood polygon, and then add islands inside the reservoir?

The other advice you gave from your first post:

"The outer perimeter should be split into sections of less than 1900 nodes and be part of a relation and defined as "outer". The islands should be mapped as islets and include other attributes such as "scrub" and be defined as "inner" within that same relation-number! Quite easy really."

is fine but I think you're forgetting that there was that pre-existing wood multipolygon into which the reservoir had to be inserted. How should I have handled that situation?

Thanks the the feedback and the helpful suggestions.

Dave

Mapping in Thailand about 1 year ago

dcp

Thanks for the info. I've already seen the f4 maps and they are indeed impressive

Please clarify how the reservoir can be defined with role outer when it is already enclosed within a larger wood multi-polygon, a polygon whose role is also "outer"

Someone else mentioned the idea of splitting the outline into two smaller pieces, and then making them part of a relation I have not done that before and would be afraid to try it. I can also assure you that I will not attempt to make such a node-heavy polygon again.