Tag Archives: featured

Every Person in Great Britain Mapped

A follow up to my previous post: Every Person in Scotland on the Map. Winner of the 2016 OS OpenData Award for Excellence in the use of OpenData from the British Cartographic Society.

Full size interactive map.

The mapping process is pretty straightforward, and not accurate. I don’t know where you live. But I can make an educated guess.

I simply amalgamate the two sets of census data from the NRS (National Records of Scotland) for Scotland (2011 census) and the ONS (Office of National Statistics) for England and Wales (2010 census).

Postcodes were then created based on the ONS Postcode Directory, filtering for postcodes that were live in 2011 (which is the latest census data). The postcode centroids were turned into polygons using voronoi polygons.

Then we simply select all of the buildings in a postcode from Ordnance SurveyOpen Map product, filtering out most schools and hospitals. Then we put a random point in a random building for each person in that postcode.

I would have loved to include Northern Ireland, but the Ordnance Survey of Northern Ireland do not have an equivalent open building outline dataset, like Open Map from the Ordnance Survey.

Rendered with: QGIS tile writer python script. Processing done 100% in PostGIS.

Every Person in Scotland on the Map

Winner of the 2016 OS OpenData Award for Excellence in the use of OpenData from the British Cartographic Society.

Full size.

The mapping process creates a random point within a building shell inside of a postcode area, which is repeated for every person in a postcode. This is in contrast to a simpler process, which does not take into account buildings at all, working simply with postcode areas. This can be seen in my previous post: Population of Scotland Mapped

Inspired by:
The Guardian – Every person in England and Wales on a map by Chris Cross

Based on the 2011 Scottish Census population data.

Data from the National Records of Scotland.

Combined with the Ordnance Survey, Open Map product.

Rendered with: QGIS tile writer python script.

Schiehallion – Contour lines and Maskelyne’s observatory

As seen in Trail Magazines 2015 October issue:


In 1774 large science was taking place in the heart of Scotland. Two men were about to weigh the earth. This was done using plumblines and measuring how much the hill in Perthshire, called Schiehallion, displaced them. Schiehallion was chosen for its uniform appearance and relative accessibility.

The two people responsible for the experiment were the astronomer Nevil Maskelyne and the surveyor Charles Hutton. Charles Hutton, in order to make calculations of the volume of the mountain, pioneered the use of contour lines. These were essential in joining up measurement points to create a continual observation. Maskelyne set up a cabin on each side of the mountain where he could live and take astronomical observations and plumbline readings. The hut on the north side of the mountain famously burned down during the whisky fuelled celebrations of completing the observations, taking with it a local boys precious fiddle. Upon returning to London Maskelyne compensated the boys loss by sending him a replacement fiddle, a Stradivarius.

A good account of the Scheihallion experiment can be found in Rachel Hewitt’s: Map of a Nation. Which also provides an excellent account of the early days of the Ordnance Survey.

My goal for the trip was to find the remains of Maskelyne’s ruined observatory, which according to some reports could still be found on the northern slopes of the mountain. The quest was inspired by Simon Ingram. Whose account of climbing Schiehallion in Between the Sunset and the Sea is definitely worth a read. I used the notes found in that book to narrow the search area.

Also available for free from Audible: Free 30 day trial

I set off, driving past Dull (Paired with Boring, Oregon), which was not a sign of how the day would turn out.

Dull and Boring

The first views of Schiehallion do not show the characteristic conical shape, rather a gradual slope.

First glimpse

However the uniformity can be seen in the Ordnance Survey One-inch to the mile, Popular edition, Scotland, 1920-1930.

At the head of the car park there is a memorial to the observation work that took place on the hill.


Schiehallion from the car park (parking is £2, and only coins are accepted), with a suggestion of nice weather ahead.


Unfortunately the weather in Scotland is never predictable. With hail one minute.


And sunshine the next.


View from the top of Schiehallion. My goal was to attain the summit, and on the way down break off from the path and head downslope.


The remains of the Ordnance Survey trig point at the top of Schiehallion.

OS Trig Point

The view of the northern slope, so the observatory remains would be somewhere down there. There were a couple of promising piles of rocks that could be seen from up high, but upon closer inspection turned out to be… piles of rocks.


View back up to the ridge.

View back

Northern slope. The terrain was not difficult, but the weather was not ideal.

View down

I was just about the give up the search, but after climbing one final rise I saw a suspiciously uniform pile of rocks.


The remains of Maskelyne’s observatory. One platform was for the cabin, with the other one for the astronomical instruments.

Maskelyne's observatory

Backpack for scale.


A job well done. The way back was very boggy. I took some solace in the fact that I was contouring around the hill that established contour lines. I was also spurred by the success of actually finding the site.

Happy Mapper

Final view back to Schiehallion.

View back

A successful journey, and excellent adventure.

If you want to visit the site I would recommend reading the description in Simon Ingram’s: Between the Sunset and the Sea, and baseing your own search on the description provided.

However I did track my own route, and I had been about to give up my own search before I finally found the site. So my route:


Scotland’s changing outline

In 1654 Joannis Blaeu published volume 5 of his Atlas Novus. The Atlas contained three general maps of Scotland and 46 maps of Scottish counties or regions, making Scotland the best mapped country in the world.

The Blaeu outline was influential on the outline of Scotland for the next decade to come. This is a comparison of subsequent outlines of Scotland before the 1747-1755 Roy Military Survey of Scotland truly surveyed the whole of Scotland.

The maps in this comparison are:

Excluded is the [1687] – Robert Morden – A mapp of Scotland made by R. Gordon because it essentially just follows the Blaeu outline.

In addition a background map was created from OS BoundaryLine (High Water Polyline) and converted to a polygon.

Everything is converted to WGS 84 / World Mercator projection (EPSG:3395).

For more on how the outlines were created:

Georeferencing vector data

For a history of the maps used:

Historic Maps of Scotland from Blaeu to Dorret (1600-1700)

If you are interested in buying a historically amazing map:

Blaeu Atlas Maior of 1665 – Including the atlas of Scotland.

Scotland’s changing coastline:

Scotlands Changing Coastline