A quick map that shows the location of the Titanic wreck site with graticules included:

A quick map that shows the location of the Titanic wreck site with graticules included:

I’ve driven from Perth to Sydney and back so I was curious as to what the route would look like overlaid on Europe so here it is. If you went the same distance west from Dublin you’d get to a small town in Labrador and Newfoundland called North River (population 579 in 2021).

I was recently reading the wiki page for megacities and I decided to try out the new curved callouts in QGIS by creating the below map.

I read Alasdair Rae’s very interesting post where he created a graph of Great Britain’s population by altitude. Using WorldPop data and the EU DEM I used QGIS, Seaborn and Inkscape to create the following graph for Ireland. I must do a bit of digging to see whether the *400 – 500 metre *slight bump can be explained by a discrete area…

I was talking to someone recently about the Camino de Santiago and whether it plays a role in sustaining the population of the provinces it traverses. It’s a rainy Sunday here so I sat down with a cup of coffee and decided to create a population density map using data from: OSM, WorldPop, Natural Earth and Peter Rukavina’s website ruk.ca.

It proved quite difficult to get GIS data on the route of the Camino through Spain. I first downloaded the *Spain.osm.pbf* file from Geofabrik and filtered it using Osmium however no matter what combination of tags and names etc. I used, I couldn’t get more than a few thousand disjointed lines that were not fit for purpose. I then found Peter’s website where he had the route as a geojson that I could easily use. I then spent some time in QGIS making the below map. I purposefully didn’t use the minimum and maximum numbers in the legend as I didn’t think it would add much value instead I used low to high.

I also haven’t marked that it’s technically the *Camino Francés* as it’s the most popular route.

To answer the population question, I buffered the route by 5km and counted the number of people that live within this area. It worked out at **1,316,141** or **2.77%** of Spain’s population, I was surprised, I thought the figure would be significantly larger.

I’m hopefully going to get a chance to get some decent maps out from the latest census so I’ve started with an easy win.

I was home recently and drove up to the top of Knockanore, a hill just outside Ballybunion, Co. Kerry. Its elevation is 267m and is by far the highest hill in this part of North- Kerry. This got me curious — how much of Kerry is greater or less than this elevation? Below is a quick map I put together from the EU-DEM courtesy of the European Environmental Agency. It turns out 267m is higher than 82.7% of the county, interesting. There’s a story that does the rounds colloquially in North Kerry that, on a clear day, it’s possible to see five counties from this elevation. If I’ve time in the next few weeks I’d like to create a viewshed to test this.

I made a quick map during the week of the birthplaces of Irish Taoisigh. The below gives a quick overview however I thought putting a cartogram together also might below. No surprise to see Dublin has the most. I know we’re a young country but I found it interesting the number of counties that haven’t had a Taoiseach.

I recently moved to the south-west of Western Australia, close to a town called Busselton. The town is famous for, among other things, the longest timber-piled jetty in the Southern Hemisphere (at 1,841m). The first time I walked the jetty I stood at the end and gazed out wondering if I could follow my gaze in a *straight* line where would it make landfall?

To answer the question accurately there are two concepts worth noting. The first is that of a rhumb line — if I digitised a line (in a projected coordinate system) representing the jetty and extended that angle, it would result in a rhumb line which at the intersect point would be off to the order of a couple of hundred kilometres.

The shortest distance between any two points on the surface of the earth is the minor arc of a great circle. So if I was standing where the signpost is shown above, that is in the centre of the end of the jetty, I would need to create the minor arc of a great circle line. This would be, as the great circle wiki article states ‘*analogous to “straight lines” in Euclidean geometry*‘.

The process I followed to create the line was as follows:

- Create two points at the end of the jetty to represent the angle looking out.
- Create a line between the two points.
- Calculate the angle of the line and extend it for 1/4 the circumference of the earth at the equator.

The below GIF visualises the process-

If you’d like to carry out the same analysis yourself below is the SQL code. I’d like to thank Darrell Fuhriman for his help.

-- assume two points, calculate the angle, then extend it. -- point 1 = -33.6307920509579, 115.338797474435 -- point 2 = -33.6290969607648, 115.338316140276 SELECT ST_Segmentize( -- break it up into segments so it looks better when re-projecting for display ST_MakeLine( ST_SetSRID(ST_Point(115.338797474435, -33.6307920509579), 4326) -- starting point (ST_MakeLine expects projected coordinates) ,ST_Transform( ST_Project( -- find a point a long way away to use as the second point in the line ST_Point(115.338797474435, -33.6307920509579)::geography -- starting point again ,10000000 -- 1/4 circumference of earth at the equator (should get us far enough) ,ST_Azimuth(ST_Point(115.338797474435, -33.6307920509579)::geography, ST_Point(115.338316140276, -33.6290969607648)::geography) -- angle between my two points )::geometry, 4326) )::geography ,20000 -- break it into segments of 20km );

An imaginary line from the end of the jetty travels 802km before intersecting with Tamala, WA. It then travels for another 2,127km before meeting the district of Ayah in the Kebumen Regency in the province of Central Java, Indonesia. Where it meets land is almost equidistant between the towns of Kebasen and Kebumen (the latterhad a population of 131,750 based on the 2020 census [source]).

If you’re taken by the above and you ever want to travel to where it touches land in Indonesia, the coordinates are: -7.7628936, 109.4018789.

For Halloween this year I wanted to create a spooky, atmospheric map. I settled on mapping the castles of Europe including Bran Castle. I know that Bran Castle doesn’t actually have any historical links to Bram Stoker but I thought it would be nice to include given it’s reputation. I came across a great website called https://download.osmdata.xyz/. It allowed me to easily download a geopackage of all the *historic* tags from OSM.

Now the the elephant in the room — the actual castle data. I filtered the data by *historic=castle*. I has tried filtering it by categories such as castle_type but there just wasn’t enough tagged to make a nice map. People commenting on Reddit have been at pains to point out how inaccurate the map is and by and large they are correct. It’s the best that could be make with the data available and I usually wouldn’t publish something where I know the data wasn’t up to scratch however as this was only meant to be a fun Halloween map I thought an exception could be made!

Anyway, I hope you enjoy it (above data caveat aside) as much as I enjoyed making it. Happy Halloween!