Mapping with Tilemill
The Melbourne Laneway's web map is an interesting example of what can be achieved using the (relatively) new open-source software called TileMill.
TileMill, developed by US company Development Seed, is fast gaining traction in the web mapping community as the tool of choice, not just because it is a free and open-source alternative, but because it can create stunning multi-scale seamless maps and offers you an affordable hosting alternative to Google and Amazon.
My early testing of TileMill has proven it to be a robust piece of software that produces effective results. Creating a cartographic design is somewhat different to what I'm used to, in that a lot of work needs to be done to your underlying data before styling it in TileMill, so careful preparation is needed in understanding exactly what you want to display on your map at various scales. Also, understanding the various linestyles, point symbols and area patterns that need to be incorporated into the final map, before you start constructing the design.
Tweaking label placement is not so straightforward as traditional print cartographers may be used to. You can't pick up a label and place it eaxctly where you want, as the software labelling engine (Mapnik) does this for you, given a list of pre-defined parameters that are determined by you.
For someone who has come from a traditional print cartographic background, like myself, it takes some adjusting to design your map in code (in this case the Carto language, a CSS variant developed by Development Seed), but nothing too difficult or onerous. The on-line help for TileMill appears to be expanding all the time, and the support forums are a wealth of knowledge for beginners.
Workflow
Whilst this isn't my first map in TileMill, it's the first published map, so I'm still getting my head around the right workflow and what works and doesn't work.
I initially created a rough version of this map in Adobe Illustrator (AI) using MAPublisher to import data and edit it in the way I needed for creating in TileMill.
Colours were sourced from ColorLovers and created in AI as custom swatches. ColourLovers provides coloours in Hex and RGB formats, both of which can be used in Illustrator and TileMill.
Once the data layers were brought into AI the attribute data was edited and files were exported as shapefiles for import to TileMill.
Icons were created in AI and saved as svg format for inclusion in TileMill. One problem that cropped up was that the point symbols in the AI file were stored as symbols and copied and pasted into a new document and saved as individual files. Placing this svg file that has an AI symbol in it inverted the symbol on the TileMill map. To fix this expand the symbol and re-save as svg format.
Add layers and graphically style them as you go then work on the labelling once everything's imported.
When you're happy with the final look and feel of the product export the tiles to the mbtiles format.
Go to mapbox.com to sign up for free and publish your tiles to your account. You can be designing, creating and publishing web maps in just a few hours.
Craig Molyneux
Senior Cartographer
