Just Show Me the Airports

A problem which I think GEMMA could solve:

I need to have a map showing the locations of the five main “London” airports – and Eurostar’s London terminal at St Pancras for good measure. The idea is to show the general direction from those locations to the centre of London, to help international visitors to the capital understand where they would be arriving in relation to the city itself. Ideally, I would be able to produce the map in a couple of minutes, without needing to open up a graphics program or do anything fancy.

First I tried Google Maps:

No sign of any airports there (& similarly for the satellite view or terrain view).

Then I tried OpenStreetMap‘s default “Mapnik” layer:

A little better, in that the airports are shown – but they are rather hard to see in the sea of other detail that you tend to get with this style. Also, there are other airports shown, with the same symbologoy, that are really not important and don’t really deserve to be in the same league as Heathrow, e.g. Redhill Aerodrome and Elstree Airfield.

Then I tried Cloudmade. The Cloudmade maps are based on OpenStreetMap, but have many styles available. Crucially, they allow editing of the styles, to change colours and line widths and toggle on and off features at different scales:

Unfortunately at certain zoom levels, some features are just not allowed. Airports thankfully are allowed at the zoomed-out level I’m using, but there’s no option to increase the size of the “airport” logo, or force its name to be shown. Slightly confusingly, the airports appear under the “aerodrome” section rather than the “airport” section. The generalisation has also obscured London City Airport completely. (Using other initial styles may produce better results.)

Finally I went back to Google Maps and used the “My Place” functionality, which I think used to be called MyMaps:

There’s a lovely custom airport icon, but no way to add a caption below the icon, to help distinguish which airport is which.

I also tried the OpenStreetMap Static Maps API which is a similar idea, but has a similar shortcoming in that you can’t label the pins.

So, perhaps GEMMA will be able to fill the gap of providing an easy way to produce a simple map with captioned pins. I think this will be achievable with four things:

1. An uncluttered base-map. The GEMMA team is still deciding about OpenStreetMap vs Google Maps for background mapping. Currently I’ve swung quite a bit in favour of Google Maps (v3 really is quite nice.) It’s easy, almost trival, to produce a greyscale basemap in Google Maps:

The above example is, incidentally, also highlighting the features in OpenStreetMap that include “airport” in the name, in turquoise, using GEMMA’s OpenStreetMap Feature Highlighter functionality. Not very useful in this stage as it’s not captioned and includes those unimportant airport locations.

The relevant code for this, using the Google Maps v3 API, looks like this:


var style = [
{ featureType: 'road.highway', elementType: "labels", stylers: [ {visibility: "off"} ] },
{ featureType: 'all', stylers: [ {saturation: -100}, {lightness: 50} ] }
];

2. Use of the shiny new Mapnik MemoryDatasource, which appears in Mapnik2, the unreleased next-generation version of Mapnik that we just happen to already be using for GEMMA.

3. Use of the really quite sophisticated ShieldSymbolizer, which guarantees the appearance of both an icon and an accompanying caption. You can change the text colour, font and relative positioning, and even the size and colour of the “halo” around the text.

4. Mapnik-based on-the-fly map tiling, as used for the already-built OpenStreetMap Feature Highlighter. Instead of using a PostGIS datasource and a copy of the OpenStreetMap database, we use a user-specified point-and-click datasource, and a Mapnik2 MemoryDatasource.

…now we just need to build it…

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2 comments

  1. […] GEMMA project recently walked through creating a map of the main London airports without specialised software or knowledge. It seemed their child of 10 might struggle to make an […]

  2. Good to know anyway that the word ‘aerodrome’ is alive and well, whatever Collins Dictionaries may think (http://www.guardian.co.uk/books/2011/aug/21/endangered-words-collins-dictionary).

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