Thursday, February 16, 2012

Basemaps and Learning Curves

I'm up against the wall in terms of time still so short blog post today on a couple of topics both via James Fee.

Subtle Basemaps:  one of the basic problems with mashups has been putting data over a map designed for route planning.  Recently with Google maps API v3 and tools like tile mill people have started de-emphacizing background maps so that the data stands out better against the background map.  I agree with James that the OSM bright minimal style is a interesting development in this line of work.

I'd love to see some user test results to see how people fared working with a mashup based on this base map.

Learning Curves:  Also via James I read a great quote about teaching OS mapping software to students.
"One of the trepidations I have with teaching mapping courses using open source is that it usually requires some modicum of programming which is always way beyond the scope of any beginner class about making maps.  In addition, open source tends to favor linux or unix based tool chains that require config/make/make install tap dance before starting anything. This is akin to telling folks that they will need to forge their tools before they can start building a dog house."
Amen to that (emphasis mine).  I'm teaching web cartography at the moment mostly using Google Earth because I want them to learn about color, symbology and chart junk, not some abstract javascript that they will forget a week after the course is over.

The rest of the post goes on to explain why Sophia thinks TileMill for windows is a game changer.

Wednesday, February 8, 2012

Grids are good

Excuse the use of map inserts rather than screenshots, I haven't got much time at the moment.

Look at an old Ordnance survey map of the uk and you'll see it's covered by a thin, blue lined grid.  On recent map systems such as Google Maps and OSM there is no grid.  My discussion today argues that we should bring the grids back.

Grids No Longer Necessary?  To locate yourself on an old map such as OS a grid allowed you to use grid references.  Web maps produce points at the right place without such a grid so because a grid adds to the visual clutter of a map, we're best rid of them?


Landmarks and Scale:  A grid is helpful because it gives a sense of scale to the map.  If you're looking at part of the antarctic

View Larger Map

 you have no sense of the size of what you're looking at.  Fix a grid of 1km spacing over the top and you can immediately judge distances.

Point Landmarks.  To locate yourself on a map your brain looks for known features and fixes your position in relation to this point.  Here in London that means that Londoners often describe an area in relation to underground (=metro) stations because that's how most of us get around.  The problem with this is that in tests it's found that people tend to position points that they remember by a landmark too close to the landmark.  So if my house was 1 mile away from Clapham South underground station if I was tested I'd tend to draw it closer, say 3/4 of a mile.

Line Landmarks Another way we locate points is in relation to line features such as a major road or coastline.  This has problems too.  Consider the question, which is further west of these UK cities: Glasgow or Cardiff?

View Larger Map

 Glasgow is towards top of map in Scotland.  Cardiff is due west of London and Bristol, you may have to zoom out or in a little 

Without looking at a map most Brits think that Cardiff is further west.  That's because they have a mental map in which the East coast of the UK runs north south whereas it actually runs NNW-SSE and they warp space to accomodate this misconception.

Grid Solution Because a grid runs exactly north-south and east-west it gets over the Glasgow-Cardiff problem.  Also, it minimises the underground station problem as it represents a continuous set of landmarks rather than discrete points (although this point is worthy of more testing to prove this is the case).  So a grid can deliver both a sense of scale and a landmark system which allows people to fix positions on a map and remember their positions correctly.

When to use Grids: I suspect that its more useful to use a grid in an area without a strong set of landmarks (desert, tundra) rather than somewhere with good landmarks, if you put a grid over US cities with their right angled street systems I imagine users would ignore the map grid because the street system provides such a good system of landmarks already.