OpenStreetMap

SK53 has commented on the following diary entries

Post When Comment
Paper Maps, Paper Maps! 9 days ago

There's a recent book The Red Atlas, about these maps, and an associated website. Certainly for Great Britain, the Ordnance Survey asserts that the maps are substantially derived from their mapping and the maps are now relatively hard to obtain.

As Imagico says they are a fascinating aspect of the history of cartography. In mentioned them as an inspiration in my Woodland Cartography post some years ago.

Soviet era maps, like those of China, today may contain some topographical distortion, although perhaps not in this series which would have needed to be accurate. Some issues of this sort were discussed at the history workshop back in 2013 at Sotm-Baltics (my summary (here)[http://sk53-osm.blogspot.com/2013/08/history-workshop-at-sotmbaltics.html]).

Lastly, the maps are worth having on their own account. I'm sure you will find them fascinating.

Searching relations 10 days ago

Equally untrue that Overpass does not allow wildcards: https://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL#Key.2Fvalue_matches_regular_expression_.28.7E.22key_regex.22.7E.22value_regex.22.29

Updates to Meet Your Mappers 22 days ago

One v minor point. "Areas of Interest" is also used for the shaded areas on Google Maps, and may well be on the way to becoming a term of the art (see Stefan Keller's presentation at SotM). It might be worth using a slightly different terminology in the tool.

Creating Vector Tiles for use with iD 22 days ago

I'm not certain but you may be able to do this from within QGIS, see https://github.com/geometalab/Vector-Tiles-Reader-QGIS-Plugin/issues/63.

Delhi's longest bus route, Himachal Pradesh, counting POIs, and whom does OSM help? about 1 month ago

Now you are entering the murky realms of wrangling OSM History files. I started a month ago and am still finding irritating bugs & unwarranted assumptions in how I process the data.

Delhi's longest bus route, Himachal Pradesh, counting POIs, and whom does OSM help? about 1 month ago

Great post. This bit is oh so true "me! It helps me."

A transcript of the SotM 2018 podcast about 2 months ago

It's great to see this, I miss your old frequency of WhatOSM posts (but who am I to talk), and had resigned myself to missing out on the details of your discussion which sounded interesting. So I'm now going to immerse myself in your transcript.

And please pass my regards & best wishes to vvoovv!

Jerry

PS. @imagico: I've been thinking about layers and how deeply embedded in cartographic practice after reading the paper on stagnation in OSM. Here is a technology which truly hasnt changed.

Take a right on “Too Damn Far Rd” about 2 months ago

The image of Too Damn Far Road seemed very familiar. It is a site in Butler County, PA where the Pennsic War event takes place. Much of the infrastructure mapped there is presumably transitory during the time of the festival. However, I imagine the names of roads are those used during the event.

Mapping Cemeteries about 2 months ago

Hi Amaethon,

Thanks for the interest. I'm afraid I've not done anything more about it. Not because I'm not interested but because there are so many things to map.

There is quite decent usage of some cemetery tags on OSM now: see taginfo.

In general the problem is that even quite small cemeteries have a lot of graves, and one wants to set aside the time to map something fairly completely. The use of cemetery=sector makes it easier to plan this type of activity, and that is now quite well used.

So far in our local area we have mainly mapped graves which are protected historical monuments. Commonwealth War Graves, with their distinctive headstones, are another specific group which could be mapped as a standalone activity.

Graves are not just interesting for ancestry research. My uncle visited around 1000 graveyards in Wales, and probably a similar number in Brittany, to record which languages were used in the inscription. This allowed mapping of changes in the linguistic borders between Welsh/English and Breton/French. Similarly lichens growing on old graves can be used for dating purposes (notably in Scandinavia for tracking the receding of glaciers).

It occurs to me that mapping graves might be something best done in a group. 10 or so people could make light work of a cemetery which would be perhaps too much for a single handed mapper.

Lastly, many churchyards in Ireland have large detailed maps of the graves prepared by a commercial company

Making Detroit the Best Bike Share Map in the World 2 months ago

Excellent post, there's much in this workflow which can of course be applied elsewhere.

It's pretty neat that it's possible to sample at least some locations using Mapillary & OpenStreetCam. It may be possible to do similar things with other open data sets which represent highly visible objects (food safety ratings for restaurants & fast food is one obvious example).

I think small random (or semi-random) samples from open data would ideally be done at the outset.

I've done something like this myself looking at 180 (out of 18,000) trees in the Birmingham open data set, selected at random within 1 km of two locations which were convenient for me to survey before a hospital appointment. In the vast majority of cases, there was a tree at, or very close to the position, but a rather higher proportion of the sample had errors of one sort or another. For a mapper just wanting tree positions the data is fine, for someone wanting to find particular trees there was work to be done. The worst error was the weirdest, the data was OK, it just shouldn't have been there: about 40 or more trees which I sampled were not actually owned by Birmingham council at all: they have University of Birmingham tree inventory tags.

I really need to write my own post about all I've found in the past couple of years using Open Data on street trees, as I think there are other learning points. But I'd heartily endorse your approach here as the experiences you describe closely match my own with a different data domain.

Copying from Google Maps 4 months ago

Please remember that after the 2010 earthquake in Haiti OSM had explicit permission to use some post-quake imagery owned by Google. In any analysis please make sure to take this into account.

Surau and parking in building enhancement suggestion 7 months ago

I think the useful thing you can do is to add a description of the place_of_worship=musalla tag on the wiki. I suspect these locations which I have mapped fit this description too:

Releasing Turn Restriction Detections 8 months ago

I only checked one in Pittsburgh, and that also appeared to be mapped.

Mapping Baseball Fields 9 months ago

One example of a cluster of fields of different sizes:

Mapping Baseball Fields 9 months ago

There are many places where there are fields if different sizes: the smaller ones presumably for small children. This is also true for soccer pitches: facilities in primary schools are often much smaller than standard pitches ( and I presume smaller than the minimum regulation size, which used to be 100 by 50 yards).

Routing QA [eng] 10 months ago

For basic motor routing graphhopper with CH requires less post-processing.

Mapping Swadlincote (Derbyshire) only by strolls 10 months ago

Indeed it's great to see someone mapping in this area. Little correction we go to Derby 1 time out of 3 (every quarter).

The villages S of Swad (Coton-in-the-Elms etc) are a potential target for a footpath mapping meeting just after Christmas (more soon).

Canal and bridges 11 months ago

Don't believe the wiki: bridge_ref is the standard used in the UK.

Possibly importing USGS forest data over 1 year ago

I fully support the remarks.of Vincent de Philly & Imagico.

I have made a number of experiments trying to extract natural woodland from landsat imagery for Tierra del Fuego using tools in QGIS. Most landsat data which is relatively cloud free has deep shadows making it very hard to find suitable filtering conditions even when applying corrections for the angle of view. No doubt similar or entirely different problems apply elsewhere. Note that the Natural Earth urban areas were created using remote processing of landsat data and are full of errors.

There are active OSM contributors with real in-depth experience of processing remote imagery for detecting aspects of woodland: I'm thinking of NextGIS who created a QGIS plugin which they used for finding old-growth forests in Russia (notably in the depths of Siberia). Such people/organisations should be consulted on data quality for this dataset.

OSM works best when we don't race to complete some particular feature class with poor quality data. It is much better to be a little bit patient and allow the organic growth of the community to both work on getting additional sources of imagery/data, and to map these features. As VdP says things like Corine data require so much post-import reworking that the data is often seriously out-of-date before people get round to it.

I believe, but cannot be certain, that there is some possibility of using this, or similar data, in a similar way to the Natural Earth urban areas for low zoom rendering.

import geonames data over 1 year ago

I'd agree with @Zverik. Even for the United Kingdom geonames data is of very variable quality. I wouldn't be surprised if places local to you are incorrectly located or their names are not immediately recognisable to you. Often they are extracted from old US military maps and transcription of names may not follow modern standards; furthermore in many places some names may no longer be used. See what I wrote about geonames in Pakistan a while back.

Nothing is more valuable than the knowledge you yourself have. I know it is frustrating when there are places lacking in detail, but OSM seems to work best with a slow but steady approach to adding data. The Tortoise not the Hare (https://en.wikipedia.org/wiki/The_Tortoise_and_the_Hare).