Category Archives: Uncategorized

The Netherlands from above


A Dutch project called Nederland van Boven (Netherlands from above) shows beautiful interactive maps and visualizations.

The making of video on YouTube is particularly beautiful:

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Filed under Education, Environment, traffic, Uncategorized

Road fatalities visualised on a map


Not always is it meaningful to map everything that has a coordinate. Recently visualisations of road fatalities appeared on the web that used public data to show every death on every road in a relatively large period on a map. The amount of data concerned resulted in a map that looks similar to a visualisation of the traffic density, which highly correlates with the population density. Hence, this map does not really provide a new perception. I’ll give following map by the BBC as an example:

 

A smart but simple visualisation by FlowingData breaks the data down into seasonal variations instead of spatial ones. This way new interesting trends become visible like the higher number of accidents on weekends or through the summer months.

 

In case one wants to use the coordinates included in the data, it would make sense to combine it with other spatial information such as traffic density on certain road sections. This way spatial centers of gravity for road accidents could become visible.

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A magazine made of infographics


what a great idea! A picture book for adults called IN GRAPHICS! I got mine last week and have been browsing through a bit. It is rather a pieace of art than a magazine and it comes along without any advertising. That is probably the reason for the high price: 22€. But it is worth the money since it represents a unique collection work that shows the whole power of infographics and various classic and inovative ways of commuicating information. One can find more than just numbers put into nice graphics. There is something playful in some of the topics like the average national anthem composed from 32 different anthems. Maybe this kind of content is welcomed by the reader who needs a little break from the otherwise demanding content that is too complex for just a quick look. The next edition is supposed to be published in 6 months, probably just enough time to thoroughly explore the 1st edition. By the way, the magazine comes completely bilingual in German and English.

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One year of blogging


My blog gets one year old! Time for a resume. I did not manage to produce as much own content as I wanted. But at I did blog at least once per month usually several times per month. So far so good. We’ll see what the next year brings.

Here are some stats from the past year:

My blog got about 4-5 visits per day on the average. Best day was November 18th, 2010 with 30 visits.

The by far most popular post was: Map Critique – Population of People and Sheep in New Zealand

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Visualizing Met Office Temperature Data of Britain


Central and Western Europe are freezing these days. Such widespread frost and snow at this time of the year is quite unusual and creates the appearently inevitable chaos on road, rail and in the air. Since even Great Britain is hit hard by this early winter the guardian’s Datablog came up with a list of temperatures measured throughout Britain on December 20th. The temperatures are quite impressing – -18.7°C in England is quite something.

The plot of the measuring stations on google maps on the article’s side to me is nothing but playing around. What we want here is a decent map that visualizes the distribution of the temperature.  One comment below the article linked to an application called bime. The “Heat Map” seems to me like a visualisation of the density of the measuring stations. At least one can use a slider on the right side to limit the range of temperatures displayed, but a comprehensive overview is not given. When switching the rendering mode to graduated circles the visualisation does not make sense at all.

Another google mashup that enables querying of the data is also linked: http://homepage.ntlworld.com/keir.clarke/web/cold.htm. I am not really satisfied with that either. The shown visualisations don’t represent the theme temperature as the continous phenomenon that it is.

The authors encourage their readers to download the data as spreadsheet and let them know what they did with it. So here it comes:

My suggested solution is the following:

  • download the data as spreadsheet
  • import it in Quantum GIS by using “Add Delimited Text Layer”
  • add a shapefile with outlines of Britain; for some reason my outlines do not exactly match with the plotted stations, since some of them are clearly placed in the ocean although they probably represent coastal towns. Since this is a rather quick hack I did not fix that.
  • use the plugin function “contours” to interpolate the temperature values; take the Layer with the stations as input, select “min temp air temp overnight” as Data Field; select filled contours; I used 8 classes to classify the range of temperatures occuring
  • now one should give meaningful colours to the contours; in the newly created layers with the temperature polygons select properties and go to symbology; select graduated symbol. The result should be a colour range of cold colors of different shades of blue, however at the freezing point mark there should be a transition to another colour, prefereably green to visually differentiate between freezing and non-freezing areas.
  • I decided to label some of the measuring stations with their corresponding temperature. In the properties of the layer I selected label and ticked “Label only selected features”. In the main view I then selected some stations with some distinct values and made sure there is no large area without a label.

Here is the result – a rather quick hack. It is not a nice finished map yet but shows in which direction it should go. I feel that the values sometimes were not matched to the classes perfectly. The plus 1.2° in Cornwall for instance should be in the green class according to my classification. So there is potential to play with it further.

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Filed under Tutorial, Uncategorized, Weather and Climate

Map of Online Communities


Today a colleague pointed me to a fancy map of online communities and social networks:

source: http://xkcd.com/802/

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Map Critique – Population of People and Sheep in New Zealand


Having had a look at Indiemapper recently I also browsed their map gallery. On top I found this nice looking map from Ben Sheesley comparing the population densities of people and sheep in New Zealand.

But looking closer I do see some things I don’t like. First of all there is a convention in thematic cartography that for population density maps one uses a color ramp with yellowish to reddish, sometimes brown colors. Darker colors for higher density. I can see these colors in the map here, but why for the sheep density? With the two subjects, people and sheep, one has to introduce a new color of course (blue was chosen here). I would have taken this one for the sheep axis and left the orange colors for the people axis as one is used to. Another thing is, and that is really a bit confusing, the circles in the map. The legend tells me they stand for the sheep/population ratio. Using point based signatures for relative values is a bit unconventional but I don’t want to blame it for that. Sometimes it makes sense to experiment a bit and break conventions. What bothers me more is the fact that the sheep/population ratio is already visualised in the map, namely by the colors, and the circles are just redundant. The orange filled areas already represent a high sheep/population ratio and not surprisingly the big circles appear in the dark orange areas.

What I like is the additional display of the dot density since this is really adding value to the map. A high sheep/population ratio alone does not tell anything about how many sheep or people there are in the respective area (could be just one lonely farmer dude and his 60 sheep). It seems the author wanted to try out different visualisation methods which resulted in a nice looking map, however I recommend always asking whether the applied visualisations make sense.

By the way, if you find something in my maps that seems unlogic, feel free to comment! My cartography is sometimes not perfect either.

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