Piskvor's Diary Comments

Diary Comments added by Piskvor

Post When Comment
Inferring Default Speed Limits

“whether a road is within a built-up area or not”

That’s the major issue around here (CZ): “source:maxspeed” alleviates this somewhat, but that’s even less frequent than maxspeed itself. OTOH, when this is determined, using the defaults is useful - maxspeed with source:maxspeed=sign/zone shows local variations.

What does "privacy" mean for OpenStreetMap?

“This has even been a relevant consideration for the otherwise ordinary residences of very famous people.” - are you referring to the Streisand effect? ( - TL;DR: attempts to censor one photo of an otherwise uninteresting house, out of many such photos, did have an exactly opposite effect)

GPS to have it's 2ⁿᵈ Y2K Moment on April 6 This Year

@alexkemp: Actually, it doesn’t even need accurate time to begin with - that’s just a helper for obtaining a GPS fix faster. Without, the fix is still usable, but a) more satellites are needed and/or b) time to fix is increased. Old GPS receivers had no RTC clock, the GPS fix has 4 coordinates (X,Y,Z,time).

Added homes in neighborhood

Yup, that’s exactly what Humanitarian OpenStreetMap Team does:

January 15 and 16

Perhaps the houses can be tagged with and …level?

Monitor OSM changes

There’s “Labels and filters” -

I do agree that it’s not entirely user-friendly to set up, and if you only ever need one simple filter, setting it up would be a hassle. Anything more, and in my experience the overhead of tuning a custom script becomes significant.

Monitor OSM changes

Interesting - why not OSMAT?

How much is too much?

I would say that you’re reaching the limits of iD, the in-browser editor. Mind you, the editor is great (also thanks to recent improvements), but is better suited for smaller edits (zooming in could help?). Try JOSM: it has feature filtering, amongst other things (and can cope with a large number of objects more efficiently than going through the extra abstractions inherent in a webpage). Requires Java though, and has a steeper learning curve.

Posting suspicious features into OSMCha

Interesting and useful - but you want to revoke your token ASAP. Pixellated block of ~8 letters of the [a-f0-9] set is just as good as posting it in plaintext:

BBC News article on Snapchat incident

Yup. And reverted in short order - constant vigilance and whatnot.

Dual freq GPS and map alignment

Even if you do manage to capture a trace with 0.3m precision, and align it with a similarly precise map (!), what next? Other map users will still come by casually, with a zoom level where a precision <5m is indistinguishable, even if in 5 years the majority of their chipsets would give them a <2m precision.

In other words, going from ~5m to <1m accuracy might be useful eventually, but requires cooperation all across the stack, not just at the surveying end - and the returns are diminishing rapidly at this scale. In my opinion, getting a collision (“edit war”) between two micromappers will still take some years.

Take a right on “Too Damn Far Rd”

Nice work - could this take non-English data into account, or does it only work for one language currently?

@Adamant1: there’s loc_name for local names - e.g. this tunnel has an unofficial but widely recognized local nickname, unrelated to the official one:

On the other hand, although personal mapping does serve a purpose, it’s often a very different purpose than the rest of OSM data: POIs named “I left my car here”, “my appartment” and “change here to go to Piskvor’s place” are transient and not useful beyond the mapper who added them. (As a resident of a tourist destination, I see these all the time.) Perhaps an app that allows for personal, non-shared markers would serve those better (e.g. OsmAnd, Locus); I think that the users who submit those (e.g. in Maps.Me) have no idea they’re adding them to the public database and no intention to do so (as opposed to the other additions, e.g. restaurants).

With better tagging tools, I’m seeing a decline in name=this is an X during the past few years - that at least is a solvable problem, methinks.

Why does OSM default render highway=path as a cycleway?

This does seem to have an (old-ish) issue open at Github:



access:lanes=bus psv taxi (oder =bus,psv,taxi ?)
Aber was in turn:lanes=? ? ? sein soll…? :(
Fake University has Fake OSM maps?

It does say “© OSM contributors / modified by SUI”, but I would not have noticed and would have fallen for it, too :D

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(It may not be obvious from the above, but GPS and barometric altitude are not all we’ve got: there are the geosurveys done by traditional methods, and there’s Shuttle Radar Topography Mission data, which is used by many OSM renderers for hillshading)

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Hello, that’s an interesting idea - getting an estimate from a few surrounding points. It sounds somewhat simpler than using external data, but what is the expected use? Most things tagged with ele are mountaintops and suchlike - generally things where the point elevation is significantly different from the surroundings.

In the case of elevation, I think that almost-contiguous coverage (most notably SRTM: ) is where it becomes useful - e.g. a trip between 800 m ASL and 700 m ASL sounds unproblematic, unless there’s a 1500 m ASL pass inbetween.

As for adding ele=*, check that your readings match those obtained by the traditional surveying methods - both barometric and GPS’s simplified geoid elevations tend to err in tens of meters from the official survey marks around here (but SRTM generally matches to a few m, except for some of its digital artifacts). It might be useful to also add the elevation where officially surveyed, and especially to mark the source of the elevation data.

Landuse import - is there one done right?

There are of course glitches, but most of the data is precise and doesn’t clash with existing features…plus it wasn’t imported full-auto, there was a manual verification/correction step before upload.

Using Wikidata data, fixing wrong wikipedia and wikidata tags

From what I’ve seen so far, there are many weird Wikipedia/Wikidata links around; this is indeed a great way to flag them for review.

Some improvement suggestions: has a contact:website= , so no need to suggest website= if matches.

The “wikidata for event” warning should perhaps be less authoritatively worded - or do you mean “if it is a battle memorial, it should have its own wikidata item linking to the main item”? E.g. this:

Using Wikidata data, fixing wrong wikipedia and wikidata tags

Hello, this looks immensely useful! I would like to try this, but I don’t have recent knowledge of any of the available areas. If it’s not too much bother, could you add Prague, Czech Republic?