OpenStreetMap

Diary Entries in English

Recent diary entries

Gedling as Big Brother?

Posted by alexkemp on 29 June 2016 in English (English)

The main trunk roads out of Nottingham are on the West & lead either to or across the M1 (the main English east-coast 6-lane motorway built in the 1970s). On the East side – which is where I live – most of the roads leading out of the town are B-roads, such as the B686 which can eventually take you to Southwell (pronounced locally as ‘suth-ell’) and Newark. That road is better known in Nottingham as Carlton Road then – at the point where Nottingham ends & Gedling begins – as Carlton Hill. At the top of that hill is (surprise, surprise) Carlton + Carlton shops.

If you are getting an impression of small-town & suburban for Carlton, then you are exactly right. The oldest date that I've spotted for a house in Carlton is 1906. The housing is mostly 1920/30s semi-detached with some Victorian (or later) Terraces + detached houses sprinkled amongst them.

The development of the shops is also a classic tale. Carlton is built upon a hill, and Carlton Hill is the road that leads in and out of Carlton on both sides. Enterprising householders at the top of the rise would have begun a shop in their front-room & extended into the back-room if successful.

However, there is not much room; the B686 is just 2 lanes and the maximum width on the pavement is only 3 metres. How very surprising, then, to see (what appear to be) two 10m+ surveillance masts in the middle of the pavement, one at either side + either end of the shopping street:

big brother masts?

I altered them to be mobile-phone masts before uplift, as I did not believe that Gedling council would be so gross as to place such eyesores in the street simply as CCTV cameras. However, after some thought I've reconsidered, and now think that yes, the police really are that insensitive. I've tagged one of them with “Big Brother?” to make it easier to find.

Coda

There were 2 buildings behind the main line of north-side Carlton shops that I needed to check out (Little Bears nursery + Dolly's Tearoom), and have just returned. Whilst back on-site I took the opportunity to ask about the mast.

The masts were erected at least 8 years ago – the owner of Bella Monty (the mast is outside her shop) moved on to the street in 2008 & the masts were already present. And yes; Gedling Council truly is that crass, because they are CCTV camera masts.

The folks at Dolly's Vintage Tearoom (on the same block as the mast) were most dismissive of it. When they moved in some years ago they initially suffered some minor vandalism, probably from kids. The CCTV neither prevented the vandalism nor helped catch the kids.

I've altered the mast in question back to “man_made:surveillance”, and have removed the ‘?’ from “ref:Big Brother?”.

PS
Counting up, there are 9 hairdressers (out of 45 shops total) on just one side of this street in Carlton:

  1. Strands
  2. Bella Monty
  3. Who's Next Barbers + Rebecca's Hair
  4. Beautiful Nails
  5. Reno & Paul Hairdressing
  6. The Ink House
  7. Kudos Beauty Clinic
  8. Hair Finity
  9. Wallis and Goodrich Hairdressing

That is 1 in every 5 shops in Carlton is a Hairdresser! Astonishing; but, I have to say, normal for Nottingham (I swear that Beeston, in the West of the city, has even more). And yes, I've naughtily included a Nail shop, a beauty clinic & a tatooist in the total, plus one of the shops is down a side-street (just), but I've also included all of the currently closed-down shops in the total number. Nottingham's girls love getting their hair done so much that they are easily able to support an army of other women + some men to attend to their every need. And the council spends thousands of pounds to watch them do it.

Location: Bakersfield, Nottingham, East Midlands, England, NG12, United Kingdom

First Video on OSM

Posted by mmahmud on 29 June 2016 in English (English)

I live in Dhaka, the capital of Bangladesh. It is a densely populated area to live in. Remote Mapping in Dhaka is also difficult because the imagery quality is not that great and the buildings are so dense that it is hard to separate from one another. However, I noticed that the imagery in Dhaka has two layers. Upto zoom level 18, there is one imagery that is quite clear but small to draw from. From zoom level 19, another imagery that is quite unclear, dense and sometimes covered in cloud. So I figured a way out to use the first imagery to draw from. I made a video about it. Here is the link:

https://www.youtube.com/watch?v=gRTnKmbbaTo

So far, this is helping a lot. I am not sure if this trick can be used elsewhere but this is worth a try.

DOST - Project NOAH (ISAIAH) finishes mapping building footprints in Cavite

Posted by feyeandal on 29 June 2016 in English (English)

OpenStreetMap contributors, through the initiative of ISAIAH (Integrated Scenario-based Assessment of Impacts and Hazards) component under DOST - Project NOAH (Nationwide Operational Assessment of Hazards), have recently completed mapping the building footprints of Cavite.

gif

One of the objectives of ISAIAH is to map the exposure elements such as buildings and critical facilities. Identifying the critical facilities such as schools, hospitals, and government offices, and other infrastructures will be essential in determining the areas vulnerable to disasters and can be used as a starting point in reducing disaster risk. All of these data will be used in improving community disaster management before, during and after emergencies. This initiative involves a collaborative partnership with the OpenStreetMap community.

Last March to April, Project NOAH conducted a series of OpenStreetMap training to its staff to digitize the building footprints in the selected provinces in the Philippines using the available imagery from Bing and MapBox. The provinces were selected according to the available imagery, land area and population of the provinces, and the available population data we have from the Philippine Statistics Authority as of 2010. Accordingly, Project NOAH created a mapping task on the HOT Tasking Manager for the province of Cavite. Since then, Project NOAH staff and OSM community started contributing to the mapping task.

Cavite Tasking Manager

As of June 28, the mapping task for Cavite is 100% complete and 18% validated. This mapping initiative helped increase the number of building footprints in Cavite from 110,506 to 631,825.

Below is the image of the downloaded building footprints in Cavite as of June 28.

Building footprints mapped in Cavite after NOAH initiative

You may view the map comparison of before-and-after edits here.

The translated building footprints data from OpenStreetMap are being utilized in one of Project NOAH tools, the WebSAFE application. It is used as an impact assessment tool for end-users to be able to readily identify the number of affected people and buildings in case a hazard scenario like flood affected a certain area. Using this tool, local government units can easily identify how many relief goods are needed to be allocated when a severe weather event happens.

WebSAFE for Cavite

Thank you for helping us map Cavite!

Project NOAH recently opened a new task for the province of Zambales. Click here to help us map the province. :)

Multi-Light Rendering and Voronoi Diagrams

Posted by Zabot on 29 June 2016 in English (English)

I spoke with B4sti and Tordanik last week about how to best attack shading with multiple light sources. As it stands, OSM2World can only handle a single light source, the sun. Adding any individual light source is not so much of a problem, some tweaks to what information is passed to the graphics card and now you have another light source. The problem is one of scalability. OpenGL breaks the faces of shapes to be rendered up into fragments. Each fragment must have its color calculated individually, based upon several factors, including the lighting. To add a second light source would require every fragment to consider both light sources. As you keep adding lights, each fragment must consider every light. This may not seem so bad, but there may be hundreds of thousands of fragments in a single frame. If each fragment has to consider 10 lights, thats one million calculations, and it only gets worse from there. But one could easily imagine a city scene with more then 10 lights, even just a highway with street lights would have more than that.

We can makes things a little bit easier on ourselves by only considering the closest light to each fragment. While this means we only have to do the lighting calculations for a single light source at each fragment, we still need to test the distance to every light source to find the shortest. We need some method to precompute the closest lighting source to each fragment so we can avoid the timing consuming process of calculating it. Unfortunately, we have no way of knowing where a fragment is ahead of time.

The solution we came up with is similar to the concept of a Voronoi Diagram. A Voronoi diagram is a mapping of points on a continuous plane to a finite set of seed points such that each point is mapped to the closest possible seed point.

Voronoi Diagram

(Each colored region would be affected by the lighting source closest to the vertex in that region)

If we imagine each seed point to be a vertex in our world geometry, then each vertex could be assigned a precomputed closest light source, and every point in the region belonging to that vertex would use that light source for its calculations. Typically, if we were to assign an ID to each vertex, OpenGL would use those values to interpolate the value for a fragment between those vertices. But by tweaking the behavior of this interpolation, we can make a fragment take the value from the closest vertex without interpolating it, and without performing any additional calculations. If we know already know which light is the closest, the calculation no longer depends on how many lights are in the scene, and the number of lights could be much greater.

Better Sunsets!

Posted by Zabot on 29 June 2016 in English (English)

After I had implemented moving the sun a few weeks ago, I realized that things looked out of place without an actual sun. So I busted out the physics textbook (google) and did some research. Sunset

The Physics

You might remember from your physics classes that light does one of three things when it strikes an object. It can be absorbed, reflected, or transmitted into the new medium. In the case of atmospheric scattering, we discount the last possibility because all of the particles are opaque. This leaves us with absorption and reflection. Absorption is fairly self explanatory, the farther light has to travel through the atmosphere, the less light is going to make it. Reflection is not quite as simple. Because the light could be reflected in any direction off of the particle, we further define reflection as in-scattering and out-scattering. Out-scattering is when light originally in a ray is reflected (scattered) away from (out of) the ray, lessening the final brightness. In-scattering is when light not originally out of a ray is scattered into the ray, increasing the final brightness. To define the final color of a fragment to a viewer, these three values most be calculated for every point along a ray from the fragment to the viewer. To see this in action, lets look at a sky without scattering.

If we consider the sun as a directional light source where all rays are parallel (not entirely true, but close enough for most purposes) then for each ray, we need only check if it is perfectly parallel to the sun, if it is then we see a bright sun at that ray, if not then there is no light and we see black. This is what you see if you look at the sun from space (Because the real world sun is not a perfect directional light source, there are several rays which are parallel to the sun, giving it its apparent size).

Absorption

The first atmospheric affect we look at is absorption. During each collision with a particle, there is a probability that the light is absorbed. The further that light has to travel through the atmosphere, the higher the probability of a collision, and the more collisions there are, the more chances there are for that light to be absorbed. If it were possible to observe a planet where the atmosphere only absorbed light, you would still see the sun at a single point, but as it lowered in the sky the point would become dimmer as more light is absorbed by the atmosphere.

Out-Scattering

Next we introduce out-scattering, the effect will be similar to that of absorption, as light is removed from the ray but the process is slightly different. To examine it we need to look at the two types of scattering, Mie scattering and Rayleigh scattering. The two are different names for similar phenomena. Mie scattering is seen when the size of the particles doing the scattering is comparable to the wavelength of the light being scattered, such as water vapor in clouds, or smog and other large particles close to the surface. Rayleigh scattering is when the particles doing the scattering are much smaller than the wavelength of the light, such as the nitrogen in the atmosphere. Going to much further dives into some serious physics, but the important thing to take away is that Rayleigh scattering scatters shorter wavelengths (blue) more than it does longer wavelengths (red), while Mie scattering scatters all wavelength equally. During sunrise and sunset, the light from the sun has more atmosphere to travel through, so much of the blue light is scattered away, giving the dawn and dusk sun its red color. During the day, there is less atmosphere between your eyes and the sun to scatter away the blue light, and we are able to see it as the color of the sky.

Implementation

In reality, every ray of light is eventually absorbed by something. Unfortunately, simulating the lifespan of every individual ray of light, potentially through dozens of bounces through the atmosphere can be incredibly computationally intensive. To make calculations easier, instead of simulating every bounce, we assume that once a ray has been out scattered, it effectively disappears. Now we can combine these two effects into a single factor, extinction, and model it as an exponential decay.

vec3 extinction(float dist, vec3 initial_light, float factor) {
    return initial_light - initial_light * pow(scatter_color, vec3(factor / dist));
}

scatter_color is what really defines the color of the sky, you can modify it in your config file by setting scatterColor = #xxxxxx. This color specifies how the sky scatters different colors of light. The gist of it is that a higher a channel is set, the more of it you will see in day time, and the less you see during sunrise and sunset.

Now we're getting somewhere, but we need some more support equipment if we want to render a sky. To calculate the amount of light that is lost to extinction, we need to know how much atmosphere the light is traveling through. This function is the product of the law of sines from trigonometry and a circular cross section of the atmosphere through the center of the earth, the viewer, and the point where the a ray from the viewer leaves the atmosphere.

float atmospheric_depth(float alt, vec3 dir) {                                                             
    float d = dir.y;
    return sqrt(alt * alt * (d * d - 1) + 1) - alt * d;
}

We have everything we need to define out-scattering and absorption, but we still need a way to define in-scattering. To calculate in-scattering, we use a phase function. This function estimates the probability that a ray will be scattered an angle alpha away from its original direction. This phase function comes from this GPU Gems article.

float phase(float alpha, float g) {
    float a = 3.0 * (1.0 - g * g);
    float b = 2.0 * (2.0 + g * g);
    float c = 1.0 + alpha * alpha;
    float d = pow(1.0 + g * g - 2.0 * g * alpha, 1.5);
    return (a / b) * (c / d);
}

To color the rest of the sky, we sample several points along a vector from the eye to the fragment we are trying to color and calculate the probability that light will be scattered from the sun towards the viewer. We scale the probability by the intensity of the sun to calculate the amount of light being scattered from the sun towards the viewer. But this light isn't done yet, it still has some atmosphere to travel through, so we calculate the amount of light that is lost going from the sample to the viewer. We add together the light from each sample point to find the total light that reaches the viewer. You can read the rest of the code here, and have a look at Florian Boesch's excellent article where I pulled the original algorithm from.

Manurewa

Posted by Rewa267 on 28 June 2016 in English (English)

Manurewa is the place to be right now.

Location: -29.191, 174.413

Let's pretend like Maps.me contribution is an import.

Posted by BushmanK on 28 June 2016 in English (English)

Case of Maps.me is, in many aspects, similar to cases of Potlatch and iD (on its early stage of deployment), but in certain aspects it is special. At least, in aspect of how frequent those edits are. Since currently it is hard to reach out to every Maps.me editor user, it makes the whole situation a kind of similar to imports, where we have massive amount of data, originally not suitable for OSM, often - with questionable quality (should I remind everybody of TIGER and its consequences for American OSM?), with certain systematic issues.

If this analogy is acceptable, it's logical to apply certain import guidelines to it. Think about paragraphs 2.9, 1.1, 1.2, 1.4, 1.5, 2.1.

So, if these requirements are acceptable (I mean, nobody thinks it's impolite to require it) for imports, why it shouldn't be applied to Maps.me, or whatever editor, which increases involvement of people, unaware of OSM guidelines, or provokes systematic mistakes? I've seen comments, where people literally opposed paragraph 2.9:

Take great care to avoid damaging the database and don't leave a messy import and assume that nameless OpenStreetMap contributors working in iD and Potlatch and will tirelessly complete your work. JOSM is better at for untangling messy data, but it's still difficult and you should do this work yourself if necessary.

And, by the way, it also says:

If your import does 'go wrong', or you needed to interrupt an upload half way through, then this should be reverted promptly. ... If you don't know how to revert an import, don't do the import in the first place.

When applied to editors, it means, that if it systematically provokes avoidable wrong edits, measures should be taken to prevent them. And developers should be prepared to do a cleanup.

I hope, nobody will read this diary entry as some kind of bullying of Maps.me developers or another complain. That wasn't my intention. My intention was to demonstrate, that OSM community does have more or less detailed guidelines for quite similar situation.

GSoC: iD editor blog 3

Posted by kepta on 27 June 2016 in English (English)

Hey, I have made some major progress since I last talked about my work with iD. I am continuing my work with lane icons last time.

This is how the current lane selection looks like.

https://dl.dropboxusercontent.com/u/35525804/lane/lane_editor.gif

Also the iD is currently going through modularisation and we are tracking it here.

With the help of my mentors we decided to draw some awesome icons. You can track the update at this gitbub repo. These are some of the icons I recently created. Suggestions are welcomed.

bike bus hov pedestrian train

I am also organising an OSM hack weekend at Bangalore. If you are around don't miss this event. Link to the event http://wiki.openstreetmap.org/wiki/Bengaluru_Hack_weekend_July_2016.

punto de encuentro.

Posted by Lalalian on 27 June 2016 in English (English)

Esta plaza, ubicada en la localidad de Loma Hermosa, en época de inundaciones, sirve de punto de reunión donde se junta mercadería, agua y alimento, los cuales se reparten en zonas mas afectadas, con la colaboración de un vecino que dispone de una flota de camiones.

Location: Chilavert, Partido de General San Martín, Buenos Aires, Argentina

Weekly roundup - Suspicious mapping

Posted by manoharuss on 27 June 2016 in English (English)

Here is this week's collection of suspicious mapping observed between 20 - 24th June.

  • This changeset from a new user was observed to be deleting POI's, beach, public toilets and adding a random square without reference to the imagery or any mentioned source. This was reverted.
  • This changeset changed name of the Paracel islands from Chinese to english, changed the locality from Chinese to Vietnamese, added a traingle on the map with no reference. This was reverted by the DWG.
  • This changeset was observed to be deleting a lot of buildings and roads.
  • This changeset deleted a lot of service roads.
  • In this changeset the nodes had landuse=farmland tag.
  • This changeset had given building=yes tag to resendential areas instead of the individual buildings.
  • This changeset deleted buildings using iD editor with no explanation in the comment.
  • This changeset deleted private roads using the iD editor. This was reverted by the community.
  • This changeset added address tags to every single object in the changeset including the nodes. The cleanup of this changeset was detailed in this diary post.

And ofcourse, look forward to this roundup again next week. If you observe any suspicious mapping, comment on the changeset and let the mapper know. Mistakes happen all the time.

Happy mapping!

GPS Coordinate shortener: what3words vs Mapcode

Posted by ryebread on 27 June 2016 in English (English)

The moment I launched Navmii GPS I was presented with 3 words that looked like this:

https://map.what3words.com/

I started looking for the explanation and found that's from the service called what3words, that attempts to solve the user-unfriendliness of GPS coordinates by splitting the whole world into 3m x 3m squares and assigning a unique set of 3 words to every location:

what3words website

Now, I got all excited and thought this is going to be the best thing ever, but my wife was skeptical and made a great point:

what3words address for a Robin Williams bench has an address of "script.export.noble". Move 3 meters east and you'll get "votes.began.hours". So it is allows you to precisely locate a feature. But here's the problem - you can't infer anything from these words. Unless you have an access to a device that has a mapping available, you can't know what continent it is on. This may not be the best use case, but when you have an address of "5 Child Street, Boston, Massachusetts, USA", you can assume "6 Child Street, Boston, Massachusetts, USA" will be somewhere nearby.

Okay, so I was less hyped and started looking into the way the words are generated, and it turned out the algorithm and the data is not in a public domain, and you need to use their REST API or offline SDK to perform the mapping.

Our goal is for what3words to become a global standard for communicating location. At the moment, the core what3words algorithms and data are not in the public domain. In the future, we may release some or all of our source code – we will continually evaluate the business case for doing this.

http://developer.what3words.com/pricing/

And then I've read this in their API License terms:

You must not pre-fetch, cache, index, copy, re-utilise, extract or store any what3words Data.

Well... you can contact them to get the SDK containing the data, but... I am not sure I like the idea of a company pushing a global addressing standard that you can't freely use. I've recently read w3w is selected by Mongolian Post office to provide addresses for locations that don't really have an official address. It will be interesting to see how this works in real life.

Another thing I encountered during my search for navigation was Mapcode (used, for example in Here Android app).

http://www.mapcode.com

Originally created by TomTom, this system does not really rely on any centralized data. The algorithm, however, is patented:

In order to prevent misuse, unauthorised alterations, copying or commercial exploitation, please note that the ideas and algorithms behind the mapcode system have been patented and that the term "mapcode" is a registered trademark of the Stichting Mapcode Foundation. Our mapcode source code is released Apache License Version 2.0.

A good thing about Mapcode is that it shortens the coordinates to manageable tokens, and you can select the representation that better suits your needs. And the best part is that you don't need any server interaction for it all to work.

[rye@delorean ~]$ python3
Python 3.4.3 (default, Jun 13 2016, 16:33:53)
Type "help", "copyright", "credits" or "license" for more information.
>>> import mapcode
>>> mapcode.encode(42.52838, -83.36005)
[('7S.65B', 'US-MI'), ('S3K.6YD', 'US-MI'), ('CDS1.XWV', 'US-MI'), ... ]
>>> mapcode.decode('US-MI 7S.65B')
(42.528403, -83.360037)

Close enough.

Okay, guess what part of the world "US-MI 7S.65B" is in? How about bugs.bumps.glue? And I am pretty sure it is easy to figure out that "US-MI 7S.659" is nearby.

On the other hand, embedding the country/state into the code can cause the same issues as the country borders in disputed territories. The location above also has an international address of "T8BB9.T204", which has the same problems as w3w one, except that there are neither bugs nor glue.

So, what do you think? Does a world need a GPS coordinate shortener and if so, what would you use?

Location: Orchard Lake Road, Farmington Hills, Oakland County, Michigan, 48334, United States of America

Home

Posted by sdilrukshini on 25 June 2016 in English (English)

Home town

Location: Thalawa Eppawala Road, Anuradhapura, Anuradhapura District, North Central, Sri Lanka

Well Done Tesco!

Posted by alexkemp on 25 June 2016 in English (English)

Tesco Carlton provide a well-maintained grassed area with trees, tucked unobtrusively between their store & Foxhill Road East. It has a wooden seat + rubbish bin, and was the perfect area on Thursday 23 June to eat a sandwich, choccy-bar + can of coke after a hard afternoon's surveying.

view from the bench

Refreshed, I went on to acquire the contact details for the Carlton Police Station (it turned out to be '999') (joke), then went home.

Location: Bakersfield, Nottingham, East Midlands, England, NG12, United Kingdom

Flood Lagoons? What Flood Lagoons?

Posted by alexkemp on 24 June 2016 in English (English)

On the Bing imagery within JOSM and (sacrilege!) Google maps (make sure that ‘Earth’ is enabled) you can find a Flood Lagoon nestled amongst all the Nottingham houses in Carlton, Nottingham NG4. The problem is that OSM does not have a “man_made:flood_lagoon” key/value, so I cannot show it to you on the OSM map (I made up what seemed to me to be the closest to what it should be but, of course, openstreetmap.org will neither store it nor show it).

Discovery:

I was surveying the even numbers on Foxhill Road Central on Monday 20 June when I came across a kiddie's playground at the corner-junction of Foxhill & Carnarvon Grove. See if you can spot in this picture the single sign of this flood lagoon (hint: it is the locked-gate entry to a narrow strip of grass + workman's hut at the back of the playground):—

Carnarvon Grove Play Area hiding a flood lagoon

My spider senses were tingling, but none of the locals that I asked knew what the hut was for.

Whilst entering Foxhill Road houses on to the OSM Map the next day I came across the Flood Lagoon on Bing, and very mysterious it looked indeed. I contacted Severn Trent & explained what I was doing & asked what on earth it was. She got out her own map & it was then that I discovered that it was “Flood Lagoon 5805”. I put it up on OSM, even though I knew that I was just wasting my time.

Yesterday (Thursday 23 June) I returned to survey the odd numbers on Foxhill. This time I was determined to see if I could get a photo of the lagoon. Fortunately for me there turned out to be a clear view of the lagoon from Radcliffe Gardens at the rear of Foxhill Road. I took a number of photos; unfortunately, I was also testing a new camera app on my phone, and some of them have simply vanished into the void. Two frames are left:—

Flood Lagoon 5805 pic#1 Flood Lagoon 5805 pic#1

Coda 1:

Thanks to some fast comments I've been able to find a tag documented on the OSM wiki (Tag:landuse=basin) that least allows me to show it to you on the map: Flood Lagoon 5805. That provides a viewable-outline in JOSM. Sadly, no outline in ordinary circumstances in osm.org, although the name can be searched for (“5805” could not be found previously).

Coda 2:

(Sunday 26 June)
...and now I am mighty confused. Flood Lagoon 5805 is identical in OSM to what was there before, but now shows on the map as a blue-infilled area. Is this due to some caching-issue on the server, or has there been an update in the tile-server?

Coda 3:

(Monday 27 June)
Carlton Foxhill Road Central Flood Prevention Lagoon:
(a flood prevention lagoon operated by Severn Trent) (contained within the area 426553952)

Sluice Valve 5805 (at the Pitch Close end) empties surface water from the Fairway Drive estate into the concrete channel of the lagoon. Water run-off can come from both playing pitches to the north-west of the Sports Centre and also from allotments to the north of the estate. The course of the concrete channel follows that of a stream which formerly ran here prior to development in the early part of the 20th Century (all such streams are now culverted).

Sluice Valve 6714 (at the Playground end) empties all contained water into the Carlton Foxhill Road Central CSO. That culvert (as long as I recall this information correctly, from an engineer that called me today) ends outside the Old Volunteer Pub on Burton Road.

The land surrounding the concrete channel between the 2 sluices has been graded into a deep basin to temporarily contain exceptional volumes of water during storm conditions.

Note: Severn Trent does NOT give this lagoon any name; I have therefore assigned it a sensible name for search purposes. Many thanks to Philip & others at Severn Trent for patience & explanations.

Location: Bakersfield, Nottingham, East Midlands, England, NG12, United Kingdom

Street Art: Nottingham NG4 Front Door Leaded Lights

Posted by alexkemp on 24 June 2016 in English (English)

I guess that I may be becoming obsessed, but I really like some of these front-door leaded light displays. Just 2 from yesterday's (Thursday 23 June) survey down the odd numbers on Foxhill Road (signs of intelligence? I started at the top of the hill):—

Who's that fool taking a photo?

foxhill door lights 1

Ah! Stayed out of the picture this time:

foxhill door lights 2

Location: Bakersfield, Nottingham, East Midlands, England, NG12, United Kingdom

Cleaning up data by properties using Overpass and JOSM

Posted by PlaneMad on 24 June 2016 in English (English)

The problem

A new user accidently added addr:city and addr:province tags to a large selection of objects, including rivers and individual nodes.

screenshot 2016-06-24 13 58 54 Changeset | Diff

The user mentioned that the tags were intended only for buildings, so thought I would document the cleanup for future efforts like this.

Finding all the problematic data using Overpass

It is possible to extract all objects with addr:city added by the particular user using this Overpass query.

screenshot 2016-06-24 14 05 28 Resulting features

This data can be exported into JOSM via remote control for further inspection and cleanup.

Fixing data in JOSM

Once all the data is loaded, we need to select only those objects or features that have been incorrectly tagged with the addr:city and addr:province. Since we know that the tags are valid on building ways, we will use a filter to select such tags on anything that is not a building way. We can use the find dialog (ctrl+F or cmd+F) to look for exactly this.

screenshot 2016-06-24 14 14 24 Find all objects tagged with addr:city and not a building

This selected 3,989 objects from which the tag can be deleted. Just select and delete the tags.

As a bonus got to also cleanup duplicate nodes using the validator. screenshot 2016-06-24 14 20 12

Upload with a descriptive changeset comment and all done!

Location: Citihomes Subdivision, Molino, Bacoor, Cavite, Calabarzon, 4102, Philippines

Street Art: Nottingham NG4 House Art Redux

Posted by alexkemp on 23 June 2016 in English (English)

I was eulogising about House Art in these Diaries last Sunday 19 June, starting with a fine example of etched glass set within Leaded Lights in Hillview Road. The following day I set off on a long trek down the length of Foxhill Road West, followed by Central & East. Blow me down, but it was not very long before another superb example showed up:

Foxhill Road window art

It got worse. Halfway down was the Richard Herrod Sports Centre and, just beyond it, a former golf course recently converted into a housing estate. Every single house had a similar front door!

A little earlier was a more light-hearted example of this species: a house with a red squirrel climbing up a metal fence:—

see the squirrel

Excellent!

Location: Thorneywood, Sneinton, Nottingham, East Midlands, England, United Kingdom

Is Vancouver's SkyTrain a subway?

Posted by Alan Trick on 22 June 2016 in English (English)

In Vancouver, we have a mass transit system known as the SkyTrain. It runs almost entirely above ground with the exception of a few blocks in Downtown Vancouver. On OSM it's stations are tagged with "subway=yes" and the line itself is tagged "railway=subway" and "bridge=yes".

This recently resulted in a maps.me user being confused, probably because the application called it a subway when I don't think anyone here would typically call it that because it hardly runs underground at all.

So that made me wonder, where is the error here:

  1. Does our schema need fixing? Should we use "railway=rapid_transit" instead of "railway=subway"?
  2. Should map.me and other map consumers just "know" that "railway=subway" and "bridge=yes" is not actually a subway and display accordingly?
  3. Should we just use "railway=light_rail" even though it doesn't really fit the category of light rail?
  4. Should users just live with the fact that we call all forms of rapid transit a "subway"?

Why I am supporting Brussels

Posted by Wynndale on 22 June 2016 in English (English)

Every year (most of them anyway) OSM holds its State of the Map conference where our international community get together to show off the art of mapping and to talk to each other so we can make the best map of the world.

This year we are meeting in Brussels from 23 to 25 September. Having attended State of the Map in the past I found both the talks and the opportunity to meet other mappers positive, and I am looking forwards to meeting many of you there.

Location: Boulevard de la Plaine - Pleinlaan, Ixelles - Elsene, Brussels-Capital, 1050, Belgium

Does Open Street Map have an input API? or Upload feature?

Posted by searain on 22 June 2016 in English (English)

For example, a lot of cities have the city open data, such as http://data.vancouver.ca/datacatalogue/index.htm.

And many city datasets are with geo locations. Such as public washrooms etc. Instead of let the user add one spot one time manually to open street.

Does open street allow csv files uploading or does open street map has an input api that users/developers can submit data through?

If not yet, does open street map have projects or plans to develop these input features?

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