Locating bridges

I haven't been able to get out mapping much recently, but a lovely day tempted me out. I did some OS Locator name chasing and as is often the case, the OS Locator names led me to a development with far more changes than just the ones OS Locator picks up. I will need to return again as the development grows in Kingswood. There's lots of area obviously earmarked for development but presumably waiting for the cash generated from selling the current houses to fund the next stage.

I then went to look at a newly opened crossing of the river Hull, Scale Lane bridge. It is a pedestrian and cycle route across the river very close to the museum quarter. It lead directly to a large fairly new hotel and towards The Deep, Hull's aquarium, or Submarium as they call it. If you are in the city take a look at The Deep, it is interesting. You walk slowly down to see lower and lower levels in the aquarium and then a glass lift carries you from the bottom back to the top to looking out at the large aquarium as you go.

Scale Lane Bridge, the black part swings

The new bridge is interesting too. If it opens for river traffic, gates shut at the east end and this end swings around to open for boats, but anyone on the bridge can stay on and people can still get on and off the bridge at the west end. In the middle of the bridge is a building which will be a café eventually and a small exhibition space too I think. These is a sloped cycleway and a flatter footway, except the footway has steps along it. All along the footway there are seats with views looking across the river. It didn't swing open while I was there, but it still looks quite different for a bridge and I like it.

The Arctic Corsair trawler, now a museum, beside the river Hull walkway

The main road crossing of the river Hull and beyond the tidal barrier

I then took a look at a new development close to home. The Bridgehead development is close to the north end of the Humber bridge. It looks like it will be the usual for commercial buildings: steel structured, clad with glass and shuttering. The first two buildings are under way with room for a few more. The roads are accessible so I grabbed a trace. It is interesting that cycle lanes are being included in the road layouts, since the entrance is off the A15 dual carriageway where there are no cycle lanes. Maybe a new cycleway will join up from the development to the existing cycle lanes nearer the bridge and beyond.

OS Locator chasing

I finally got around to sorting out some new OS Locator anomalies close to home. I went to look at a new small road under the shadow of the Humber bridge. When I got there the road was dug up for pipe laying. The tarmac has been down less than 3 months and already the utilities are digging it up again. As I was standing looking down the road, wondering if I should brave the excavators, a woman in a hard hat and fluorescent jacket approached me smiling. She asked if I was interested in the new houses, which are not finished. When I explained I was making a map the smile faded but she agreed I could walk to the end of the road with my GPS 'at my own risk'. Since everything I do tends to be at my own risk I collected my trace. On the way out I asked the once more smiling woman what the road name is going to be and she confirmed the same name that OS Locator has.

Next I went to Welton. Here a slightly bigger development has been squeezed into what was a farmyard many years ago. Here too the road was uneven, but only because the final surface has not been laid. None of the houses looked finished, indeed some were barely started. Here too I was approached by a florescent jacket, this time draped around a young man with a clipboard. He too wanted to sell me a house, but when he heard that I was making a map he asked me to leave as it was still a building site and not safe for the public. As I already had my trace I left, this time snapping a picture of the new road's name board - about the only part of the development that was complete.

I am used to roads showing up in OS Locator as they are close to complete, so seeing ones so obviously early in their development is a little different. Maybe OS are trying to get ahead of the game.

So do the OSMF working groups work?

I do wonder if the process of working groups really works. I have asked the Licence Working Group to make a simple action to prevent a falsehood being repeated. They did nothing and did not even respond to my emails.

I have now asked the Data Working Group to revert undiscussed mass edits. Again, no action and not even an acknowledgement email. If we are serious about stopping undiscussed mass-edits, the only real way forward is to revert them as quickly as possible to force people to follow the guidelines. If an ordinary mapper, like me does the revert that risks an edit war, especially if the ordinary mapper has already engaged with the mass-editor to no effect as in my case. The longer it takes to revert a mass-edit the harder the revert becomes because of other small-scale edits.

If the working groups are not going to take action or at least acknowledge a request or contact, then they should resign and close down the group so everyone knows that the only process open to an ordinary mapper is down to him.

Enclosures

I had a meeting today about a project in our village. Ian had a map that he has assembled of Swanland & North Ferriby that shows the villages pre-Enclosure Acts. It would be good to create an overlay with the modern OSM map for people to see how things have changed in nearly 200 years. In case you haven't guessed, the answer is lots.

I need to warp Ian's map to fit the EPSG:3857 projection, make its background transparent and then build a little app to show one layer over the other. I'll see how I get on.

A Park, Hawthorn and Rugby

I've been trying to fill the gaps in land use in Hull. I think that, generally, everywhere in a city can and should have a landuse tag and that land use areas probably should join at their edges. I have been joining, say, a residential land use to a commercial land use, sharing the nodes, so there is no gap between them. I have not been joining land use areas to roads. That is just wrong. A few land use areas stop at a boundary with a fence or a hedge, so I sometimes reuse the land use nodes to add a barrier tag, but never a road. Roads are, I think, too complex to be shared with a land use edge. Roads do fall into the land use. I residential road is part of the residential area along with the houses and occasional shop and pub too. Parks, schools, recreation grounds, cemeteries and other large areas I've generally left out of other land use - layering land use on top of, but another land use seems wrong to me. I have tried not use too many multipolygons with land use, so a pond in a park will not be a hole in a multipolygon, though it would work well if it was.

This had involved a lot of staring at aerial imagery followed by surveys to try to determine where one land use type gives way to another. There have also been a lot of areas that seem to have no land use. I have resorted to landuse=grass for space between a river bank and, say, an industrial area nearby. I'm not happy that 'grass' is a land use, but then many OSM tags have grown to be useful without their actual keys or values being completely logical. OSM is about a map database not some kind of taxonomy after all. I have also used natural=scrub in some places too. Again not sure but I think it is better than nothing. It is really urban waste ground, but that doesn't seem to be in the wiki. I have used landuse=railway for the inaccessible land fenced off beside railways which seems right to me. I think there should be a landuse=highway tag for major roads and motorways too. They often have an area of inaccessible land reserved beside them, sometimes beyond the verge perhaps up an embankment. In Britain this is usually grassed sometimes with bushes or small trees on to too. They have become useful wildlife havens.

I noticed on the aerial images a largish piece of grass on the outskirts of the city that I didn't recognise. When we went to look we found a large grassy park so I added that. It was very, very wet - flooded in parts, so I didn't venture onto it, though I will later in the year just for a look around at what lies beyond some trees and bushes and whether they too are part of the park or not.

Part of my work has been focussed on areas of Hull that are being redeveloped - and I haven't completed them yet. Hawthorn Avenue had a lot of terraced streets of it on both sides. Some had fallen into disrepair and even dereliction and the council declared the will to redevelop some of the area. I don't want to give the impression that it was or is a slum. Just some areas where becoming a mess and the houses were getting harder to maintain and costing more to heat, for example. Yesterday we took a look at the work that is progressing. Areas of Woodcock street have been transformed, with a mixture of size and styles of houses, a small park, sensible car parking, cycle ways and foot ways and the whole area looks impressive. I don't know anyone who lives there to see if there is a community spirit building, but somehow there is a feeling of a place that could be very pleasant to live in.

Greek Street boarded up

Further north along the eastern side Hawthorn Avenue the work is much less well advanced. Some streets have been partly demolished and others are boarded up ready for demolition. Sadly there are a few people who have refused to leave their homes yet and are living in tiny islands surrounded by derelict houses.  

To the western side of Hawthorn Avenue little remains of the old buildings with new buildings steadily going up, again in a mixture of styles. I have marked the areas boarded up as brownfield until construction starts. This does currently include the few houses still occupied, but I suspect not for long.

We also took a look at the old Hull FC rugby league ground, the Boulevard. The main entrance lies off Airlie Street, hence the team was nicknamed the Airlie Birds. They moved to share the KC stadium with Hull City football club in 2003. The old ground was used for greyhound racing for a while but now construction is under way for a new school, The Boulevard Academy. I wonder if they will have any rugby league teams?

Local recycling

I wanted to take some stuff to the local recycling site and was turned away because they were rebuilding it. I hadn't seen any warning about this so I searched for it by name - only I got the name wrong. I had added the site to OSM in 2008 and added the name from memory as Humberdale Waste Site when it is really Humberfield Household Waste Recycling Site.

What surprised me was that the top of my Google search came back with the OSM Node Browse results for the site - presumably because nothing else matched my erroneous name that I searched for. It probably won't work now anyway because I've corrected the name.

I should just add that I used the word Google above without stating that Google is a registered trademark. I didn't have to say that because I was not attempting to provide any services that Google offer, nor was I trying to pass off my goods or services as though they were Google's. I mention it because of a recent OSMF missive about a newly trademarked word that they are frantically removing all references to from our Wiki and Help system. We gather data and publish it under an open licence. I'm not sure I see how that might breach a patent troll's dubious US trademark that was refused in the EU, but then I'm not a lawyer, all the happier for that.

Soft style

I'm working on a project for the Hull area. I want to display overlays on a map. I want the map to be there, but not in your face. I don't want any shops, pubs or other such objects to detract from the overlay, but I do want people to be able to relate the overlay to places in the city and to the road layout. I needed my own render for the city.

At one time I might have turned to Maperitive to create a custom render. It works well but it uses .net so is best used in Windows. Windows leaves me cold. I have used the excellent Mapnik in the past to customise map rendering. Although the end results from Mapnik are superb, wrangling the xml to produce the required result was not easy to understand, so my customisations were tweaks rather than rewrites. Then MapBox released TileMill. I quickly saw how powerful it was. It uses a new style of coding called Carto to define the map style and uses easily defined layers to determine how the map is built up. Under the skin it uses Mapnik to render the example each time you save a change. One of the options is to export the Mapnik XML of your current design so you can throw that at a Mapnik instance and either generate a static image or a set of tiles for a slippy map - which is what I want.

Like any new environment it does take a little understanding. OSM data is best used by importing it into a PostgreSQL database using a recent version of osm2pgsql. This is a lossy process, intended to populate a database schema laid out for use by a renderer. Coastline is created by using a huge shapefile. I have a cut-down version just for the UK which is smaller and quicker to use. If you want to generate images at low zoom levels there are other short-cut shapefiles such as a simplified coastline and named places for example. These speed up processing at low zoom levels when massive amounts of OSM data would otherwise be needed.

Using TileMill is really about getting to grips with Carto and its relationship with the layers. Layers are each a definition of a data source such as a shapefile or a database table or a selection of part of a database table for example. The order they are listed defines the order that image of the map is built up. Carto, which is a lot like CSS, then applies the detailed use of the data in a layer to define the style of each object, such as its colour, opacity and so on. Some objects on the map may use separate layers to define them and be rendered by separate Carto statements. A road may be made up of a casing (its edge), the centre space which may well be coloured differently from the casing, and text for the name of the road to be displayed. These will be built up in different layers to make the joints between roads seamless and to ensure the casing is covered by the filler and then the text lays on top again. Then there are tunnels and bridges and all the other options the real world throws at cartographers. Layers and specific Carto statements together sort all of this out.

I have been helped in my growing understanding of the best ways to do some of this by reading examples, both that come as part of the download of TileMill and by reading the details of Andy Allan's excellent recreation of the Standard OSM map in TileMill.

To create my map, I downloaded the OSM data I needed from Geofabrik's download server, which is a simple and reliable way to get OSM data that is only a day old. I loaded it into a PostgreSQL database with the PostGIS extensions using osm2pgsql just using the default schema. It probably has all sorts of stuff I won't render, but it is quick and easy to do. Then I pointed TileMill at that and the UK coastline shapefile and set to work. Just to check all was well, when I had some of the style working I exported the Mapnik XML file to render some tiles and it quite quickly produced zoom 11 to zoom 18 for the area. I uploaded the tiles just to see how my web server responds with the tiles and all is well. The style needs a lot more work, but the process works very well, so I'm happy to put the hours in to become more of a cartographer as well as a mapper. I'm just not sure how good I'll be at it.

You can see the crude first pass here. The city will also look better not only when I've improved my style but also when the landuse gets tidied up with fewer gaps and overall more careful coverage - something Bing imagery will help with a lot.