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Entries from October 2012.

Dilemma of the day: remap capslock as backspace or escape?
31st October 2012

The dilemma of the day.

Should I remap capslock as backspace or escape?

Escape pros: makes mode switching in Vim really easy. Escape cons: I don't really use Esc much, except in vim. Perhaps there are apps where accidentally hitting esc (much easier when it is remapped to the capslock key) could be dangerous? Escape neutrals: I don't really need a handy esc for vim mode switching, because you could use Ctrl+C in Vim. That said, capslock is easier than Ctrl+C.

Backspace pros: I make a lot of typing errors, having a closer backspace would be a real help. Backspace neutrals: Perhaps auto-corrective features would eliminate the need to backspace to manually correct typos. Verdict. I think I'll go with mapping it as escape.

No tags
Cartograhpic Principles
25th October 2012

I've recently read an article which has given me a huge insight into some cartographic principles. Principles which I had been using were given the rigour they deserved.

What I gain most from it was that one kind of map among many is the physical map. The physical map is designed to portray the feeling of the environment. One way to do this is to use a suitable base landcover palatte as suggested in the article, combined with relief shading and textures to represent the environment to the fullest extent.

The use of hypsometric tints is debated. Personally I think that every map feature is fit for a purpose and hypsometric tint are no different. It is deciding what you want your map to show, and how you are going to combine these features into a single map to make it multi-purpose.

Hypsometric tints are useful for showing elevation levels (no surprise there). So for showing points above a certain altitude where the air may be getting thinner, or comparing which of these two mountains is higher, or by gauging if this is just a small hill or Mount Everest.

Contours are good for showing steepness (how close the lines are together) and identifying the gradient of a paths by if the path runs parallel or orthogonal to the contour line.

Shaded relief is great for getting a general sense of where the hills are and their form.

Physical coloured landcover combined with textures or representative bump maps give you a feel for the environment.

The next task is building up a physical map which gets applied to OSM data (possible in tandum with other free sources) which uses natural colours, shaded relief, textures and bump maps. The only question is whether to build something like the Stamen watercolour maps but with natural colours and textures, or instead work towards a natural style for osm2world (or any other osm to 3D world program).

Tags: geo.
A free and open source SRTM shaded relief and contour map
9th October 2012

I've recently pushed out a new srtm3-stylesheets repository which contains shell scripts for working with NASA SRTM DEM data, gdaldem based stylesheets for shaded relief maps, Mapnik stylesheets for contours and a TileStache configuration for sandwich those styles together into a single map.

This was spurred on by the fact that I simply needed a map which showed hills. I've used Andy Allan's OpenCycleMap in the past which has color relief and contours. Unfortunately it is closed source.

So I put my head down and hacked together repeatable scripts to get the source data up and running and some basic stylesheets to produce a usable and pleasant looking map. All released as free and open source software under the CC0 license.

Contour Map

I want to avoid adding things like streets etc, such maps could be built as separated layers based upon this style and sandwiched together, for example, with the TileStache sandwich provider.

I hope to build upon the lessons learnt here to produce a map like the Stamen Terrain map, except with the source code released under a free and open source license. Perhaps just with hill and slope shading applied to landuse with other map features placed on top.

Contour Map

Contour Map

I've rendered NSW (only server resource prevent worldwide!) as a slippy map here.

Tags: dev, geo, osm.

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