tlohde

3 × 4⅓

tlohde — Sat, 04 Apr 2026 11:17:00 GMT

outside

I went up a hill, two hills in fact, for the first time in a long time. Driesh and Mayar, a pair of Munros in Glen Clova. Near whiteout conditions were enjoyed on both summits along with some haribo tangfastics.

⛶↗ Fig 0: above Corrie Fee, looking back at where I'd come from.

made of meat

When emptying the recycling I plunged my hand into a bag unaware that it contained broken glass. This yielded a reasonably deep cut on my thumb,^[1] just above the crease, which bled an unreasonable amount. When cleaning and dressing it, I was made uncomfortably aware that I am in fact, made of meat.

I didn't climb for a fortnight. Thankfully it seems to have healed up ok-enough. Although, I have my suspicions that there might still be some glass in there.

woof

The dog had another seizure. And then last weekend managed, somehow, to badly damage a few of her nails, exposing the quick. The vet removed three nails and instructed us to bathe her feet in warm salty water after each walk, so they don't get infected.

projects

tuis

I made modest progress on my running / cycling / hiking activity viewer, adding Eddington Numbers, and some code for calculating fastest x km, both within a given activity, and across all activities^[2].

I made considerable progress on a different tui...one for my partner's business. Another interface to a duckdb database, only for managing clients, sessions and some payments. Nothing too fancy. And, remarkably, it mostly works. And I now feel a great deal more comfortable working with textual's framework, and my sql skills are improving.

Repetition is a useful thing.

bathymetry

Very tentaively started an overwhelmingly large project. Since posting that I have digitized Loch Clunie, and slightly improved my code for making the gridded output.

I have been meaning to get more comfortable just using gdal, because I get the sense that it can do everything. But I always default to geopandas and (rio)xarray. Is this a problem? Not really. I suppose.

equinox


We're now the right side of the equinox	good
I failed to mark the occassion	bad

footnotes

what do you call the inside of the knuckle? ↩︎
three cheers for numpy.searchsorted ↩︎

deep thoughts

tlohde — Mon, 30 Mar 2026 20:09:00 GMT

I was thinking about something else^[1] when the small matter of the volume of water in a lake came
to mind. I looked at a map and waded into some murky waters. Of unknown depth.

os

What can you see in Fig 0?

⛶↗ Fig 0: Loch Treig and Loch Ossian from OS Landranger 42
OS Crown copyright 2016.

Aside from the handful of Munros, the West Highland Railway and the Youth Hostel?

Well, there's the beautiful, glacially carved, Loch Treig (Fig 1) and its sibling Loch Ossian.

⛶↗ Fig 1: South West (ish) over Loch Treig from Stob Coire Sgriodain (979 m) on 6th April 2025.

But why does Loch Ossian get the all bathymetric contours and the bigger, deeper, Loch Treig gets none?

dam

Loch Treig was dammed in 1929 (dam not shown in Fig 0). After a quick glance at a few other OS map sheets I think I can say with some confidence^[2] that the Ordnance Survey have chosen not to put bathymetric contours on bodies of water that have a dam.

this makes sense

Water levels in dammed lakes—reservoirs—are liable to fluctuate.

The depth changes.

On a whim.

End. Of.

but

A given point on the lake bed has an elevation above^[3] sea level.

Yes, there is probably some infilling go on, but, the bathymetry isn't changing that quickly.^[4]

The lake shore was plotted at the elevation it was surveyed at.

Bathymetric contours are just offsets.

If the lake surface elevation at the time the depths were measured is known, the elevation (above sea level) of the sublacustrine^[5] terrain is also known.

Therefore, the bathymetric contours, or offsets, can be readily plotted whatever the lake level.

So. Why aren't they?

I don't know.

And I would like to know.

working hypotheses

No wrong answers, no silly suggestions, just some ideas as to why...

Cartographic clarity?
- ditch the contours on reservoirs to minimise visual clutter
To discourage recreation?
- don't want any fishin'-swimmin'-sailin'-paddlin'-divin' in case a hydro-engineer spontaneously opens the dam
Rates of infill are HUGE?
- any depth measurement will be out of date before you can say sublacustrine sedimentation^[6]
Because reservoirs aren't natural?
- and only natural things are deserving of contours
OS Style guide?
- a style guide written in 19-something says "we don't do that" and nobody remembers the why

If YOU know, please, let me know.

data

In the process of trying to understand this mystery I went hunting for some data.

oh, ess

I can't seem to find any reference to bathymetry in the documentation of OS Terrain 5, OS Terrain 50, or OS Water Features.

The closest I could get to the bathymetry shown on the above map is on the legend where bathymetric contours are described...

Contour values in lakes are in metres

...They aren't deserving enough of being displayed visually.

the lakes portal

The UK Lakes Portal don't include any detailed bathymetric data, but do include a few summary statistics:

Surface area
Mean depth
Maximum depth
Catchment area
Elevation

Now we are getting somewhere.

In many cases the source cited for mean and maximum depth is "Murray and Pullar". Furthermore, they include a link, such as this one, that take you a scan of Murray & Pullar's map of the lake. And what beautiful things they are (Fig 2).

⛶↗ Fig 2: Look at those blues and browns. Note Stob Coire Sgriodain (where Fig 1 was taken from) towards the bottom right of frame. North is to the right. Apologies for the low quality. This has been exported from the above link as a .pdf then converted to .jpg. High-resolution exports come at a price.
Reproduced with the permission of the National Library of Scotland (CC-BY).

The Bathymetrical Survey of Fresh-Water Lochs (1897-1909) is searchable via the National Library of Scotland's map page. And whilst they have all been scanned and are viewable online, only 33 have been georeferenced and are visible on their interactive Georeferenced Maps page.

Murray and Pullar, and their team, surveyed 562.

I did, however, find this website. Which has just for four lochs.^[7]

conclusion?

Does the lake bathymetry shown on OS maps come from the Bathymetrical Survey of Fresh-Water Lochs (1897-1909)?

I don't know. Maybe?

Is the underlying data available?

Assuming "yes" is the answer to the previous question, then, sort of.

The Bathymetrical Survey of Fresh-Water Lochs (1897-1909) is available, but the data are trapped in a raster.

What does that mean?

It means I'm very tempted to start a large digitisation project.

objective

Liberate the data contained within the Bathymetrical Survey of Fresh-Water Lochs (1897-1909).

What data?

The shoreline
- LineString with the associated "Height of Surface of Water above Sea Level (feet)"
The individual soundings (~60,000 of them).
- Point with a depth measurement (in feet)
The contours^[8]
- LineString^[9] with depth (in feet)

method

digitize

Handily, for the 33 georeferenced sheets the NLS have made a publicly accessible xyz tile available. This was added to QGIS.

Once in QGIS a new point layer with a single attribute field: depth_ft was created and points were added at each depth sounding and the associated reading input. A new polygon layer, again with a depth_ft attribute, was similarly created and the shoreline (depth: 0 ft) digitized, followed by each of the contours.

The soundings point layer was supplemented with points taken every ~150 m^[10]^[11] from the shoreline, and optionally^[12] points from the contour lines.

grid

A 5 m (25 or 50 m would have been sufficient) grid was created covering the area of the lake. All of the points were first passed into matplotlib's mtri.Triangulation to create a Delaunay triangulation. This triangulatuion was then used to interpolate the depths across the grid with the mtri.LinearTriInterpolator^[13]. The output of this is then masked with the shoreline, as some triangles and grid points fall outside of the lake.

Bingo. Gridded depths.

subtract

Elevations for the surrounding terrain were taken from the Copernicus DEM (GLO-30), because it's easy to access. The gridded bathymetry values were converted from feet to metres, reprojected onto the same grid as the DEM, and then subtracted from the DEM. Because they're just offsets.

Bingo. ✨Topography & bathymetry✨

result

Here is Loch Treig. Poorly rendered^[14] in Blender^[15]

⛶↗ Fig 3: Loch Treig from Murray & Pullar's Bathymetrical Survey of Fresh-Water Lochs (1897-1909) draped over the topo-bathy surface created from their soundings, and surface topography from Copernicus Global DEM. View is looking north-west ish towards where Fig 1 was taken from. Apologies for it being so dark.
Reproduced with the permission of the National Library of Scotland (CC-BY) & Produced using Copernicus WorldDEM-30, ESA.

discussion grumble

The contour lines aren't straight. Why?

they were hand drawn
the gridded bathymetry (and the copernicus DEM) would put them somewhere else

This discrepency means wiggly contours.

This is the reason why the soundings were supplemented with artificial soundings along the contour lines, in the hope that this would pin the lines to the "correct" elevation in the generated grid.

It helped, but not enough.

My "workflow" is semi-optimized, and I should really just start clicking away and digitize the remaining georeferenced maps. I've already done the two sheets covering Loch Ericht.

Get more comfortable in blender. Fig 3 was generated using Viewport Render Image, because I could not translate, scale, rotate, zoom, focus or otherwise manipulate and coerce the camera into position.

Nor could I make the sunrise.

footnotes

can't remember what ↩︎
there's my trademark lack of confidence ↩︎
or below, looking at you Loch Morar ↩︎
right? ↩︎
couldn't not squeeze that word in here ↩︎
not sorry ↩︎
and after starting my own digitizing efforts I found this conference talk by Phil Taylor which details his (& his students') methodology ↩︎
granted is technically a derived quantity, since these are based on the the shoreline and the individual soundings ↩︎
or Polygon if filled contours are your thing ↩︎
this seemed like a sensible-ish value ↩︎
the quality—the general "yeah, that seems about right"-ness—of the output is quite sensitive to this value, for example, at Loch Ericht, the spacing of some of the original transects means that during triangulation some triangles are formed from two adjacent points on the shore, and a third point across the loch on the far shore. This manifests itself as a non-existant land-bridge in the final gridded output ↩︎
for reasons that I might explain later ↩︎
mtri.CubicTriInterpolator is also an option ↩︎
because I struggle to use Blender ↩︎
because my laptop kept crashing when using QGIS' 3d view ↩︎

2 × 4⅓

tlohde — Fri, 27 Feb 2026 15:16:00 GMT

Not a lot. I think. I am still hopelessly in love with this peanut rayu, and I'm currently enjoying reading (very slowly) A Thousand Blues by
Cheon Seon-ran.^[1]

ill

I was snotty for a week and a bit. That halted the running & cycling & climbing discipline of last month. I have just come back from my first climb in a fortnight, and I was going ok ish.

jury service

I didn't have to go to court. I just had to phone a number every evening for four days to see if I had to go to court.

map festival

Not having to attend court meant I could go to the Map Festival at the National Library of Scotland. I didn't get tickets to any of the talks, because (a) I didn't realise I needed to. I browsed the free section for an hour or so. Had a chat with someone from the National Collection of Aerial Photography. They are digitising ~30 million images. And the film canisters are huge. ~30 cm negatives. Incredible things. I had questions about how accessible and discoverable their collection is. I didn't get an answer as to whether or not they are using STAC. And unfortunately the imagery isn't free.^[2] But that's not surprising, the cost of scanning and georeferencing that many images must be huge. They also had some stereo pairs to look at.

There were also some panoramas of Edinburgh from the late 17-, early 18-somethings by father-son duo Robert Barker & Henry Aston Barker.

One day^[3] I'll use some high-res lidar data and write some terrible code that won't quite work to make a poor imitation that won't look anything like the original, and will be far less intelligible.

projects

tui

I made some progress on my little CLI / TUI .

this site

And I tinkered with the archive page of this site, which now, thanks to the uncharted plugin, has a graph entirely composed of HTML & CSS showing the cumulative number of posts on this site. And thanks to some poorly written javascript by me, I now have a list of #ExtremePosts.

cartography

Resumed tinkering with a now very late^[4] birthday present for a friend. Still not happy with it. It might involve the pen plotter, which I haven't been able to get running since the old laptop died^[5] and I'm now using a different old laptop running Linux Mint, instead of Ubunutu. Something to do with a driver a CH341 serial driver and tty...ugh.

None of that really has anything to do with cartography.

the thing

A significant thing has been happening. Which I shalln't be sharing any details about. Other than the fact that the thing is giving the bucket of emotions a mighty stir.

the dog

The dog had two seizures this month. Bringing her total to four. We're off the vet next week for her annual check-up. Maybe she'll get some meds for it.

I'd like her not to have any more. They suck. The episodes tend to happen ~an hour before normal waking up time and start with her throwing up, then ~a minute later going into a seizure that lasts ~2 minutes. During which she goes blind, loses control of her bladder and bowels, in addition to the convulsions. After that she is, understandably, disoriented. Her balance is off, and she's can be a bit aggressive^[6] whilst working out what just happened. I stay a few metres away and just talk calmly and quietly. I think I can tell when her vision returns: the pupils start responding a bit more normally; and she moves her head more predictably. The "coming-out-of-it" phase is ~5-10 minutes, and I'll then take her out for a toilet break and my partner starts mopping. Once back, it's time to give her wash^[7] because she is invariably covered in her own urine and faeces. Once all the windows in the flat are open, it's time to put some coffee on, write the date on the piece of paper titled: "dog seizures", and start the day.

the car

Needed jump starting, because I rarely use it.

time

The days are getting longer, and milder, and for that I am grateful.

elsewhere

the infidex 176 V open source panoramic camera
Max Halford's text classification with python 3.14's zstd module
as a long time user/owner of an eTrex, this review of the new eTrex was disappointing to read
an interesting & well-written description of git scraping
excellent post about recreating a 90's Game hint Line as a museum exhibit
Lene Saile's Internationalization with Eleventy (they also have a cool light/dark toggle button)
this GeoParquet Visualizer by Dominik Weckmüller. It's fast. It should be possible to make it work with my track database & I might be capable enough to make it work.
ASCII characters are not pixels. No they are not
a how not to of data-viz
chartability: a good accessible data viz guide
enclose.horse
Use & Modify: a collection of open source typefaces
a nice post on open source maintenance
l***edIn is gross - what happens when you verify your identity
a nice portfolio site: pathfinder geospatial

grazie, ciao

footnotes

translated by Chi-Young Kim ↩︎
which makes me appreciate all the Sentinel and Landsat data ↩︎
probably never ↩︎
nearly four months ↩︎
need to try harder to get it running again ↩︎
low growling, little bit snarly, the occassional bark ↩︎
she gladly swims in the sea and lakes and rivers. But she does not like the bath ↩︎

progressing with a project

tlohde — Sat, 14 Feb 2026 23:17:00 GMT

Am I doing a poor imiation of what garmin and strava already do? Yes. Am I learning. Yes. Am I having fun. Mostly yes. I think. I should hope so.

garth

In my previous post on the matter, I mentioned that my silly little CLI would not have the the ability to auto-magically sync. And I was wrong.

Having dug into what garmindb does, I discovered garth. garth makes it super easy to grab and download data from garmin connect. Like ~one line easy: garth.Activity.list(). That's the bulk of it. Followed by some magic with zipfile.ZipFile() and io.BytesIO().^[1]

So, I can now download new activities from garmin to my ✨database✨.

magic.

duckdb

I am getting more comforable with SQL and duckdb.^[2]

Bulk-importing all my old .gpx files was reasonably straightforward; ditto the .fit files I downloaded from garmin. Having one .db file to backup feels a lot cleaner than the ~2.5k that I've been struggling and failing to organise for a few years. With the added bonus of the .db being much smaller, and it can be made even smaller if I dump the tables^[3] out to .parquet files.

I don't think I'm dealing with enough data to really benefit from duckdb over pandas. I could have skipped the database step altogether:

read in a .gpx file
do some light wrangling
concatenate it to an exisiting .parquet file

I suppose I would then lose the security that maybe comes with a database, and the ability to enforce keys exist in other tables...

As for speeed, again, I don't think I'm dealing with enough data. My points table with all the individual track points has 4.39 million rows, so maybe...

Once I've finished, I might^[4] run a few speed comparisons. Since apparently that's a trendy thing to do.^[5]

And most of the things I want this tool to be able to do sit under the "query" umbrella...

typer

I'm happy with my choice of CLI-maker-tool. This coupled with poetry have been mercifully straightforward to use.

And I now have a handful of commands that do things. These are invoked like so: trak import-bulk or trak cumulative-distance.

I've been diligently adding docstrings (not the best, but not nothing) to everything, which means I am also able to append --help and I get something that looks like:

$ trak filterd-date --help

Usage: trak filter-date [OPTIONS] START STOP

filtering tracks by date. returns track_ids NOTE: if input is yyyy defaults to start of year. to get full year (i.e. all tracks in 2025) input: date-filter 2025 2026

Arguments


start	TEXT	date string for start of time period: yyyy; mm-yyyy; dd-mm-yyyy. seperators can be any of the following: /,.:	required
stop	TEXT	date string for end of time period: yyyy; mm-yyyy; dd-mm-yyyy. seperators can be any of the following: /,.:	required

importers

For bringing data into the database. This is where the wrangling happens.

download-fit-files
import-bulk
import-track

summaries

For creating tables of summary statistics & showing distance travelled by activity type for each year, along with a some graphs.

summary-by-year
cumulative-distance

Many more of these to write...

filters

For searching the database, by time or location.

filter-date
filter-location

filter-location is a bit messy, but it works either by supplying a (lat, lon) and a radius, or a bounding box.^[6] I think^[7] filtering by location is where duckdb will outperform geopandas. Maybe. But again, I'm not dealing with HUGE data.

plotting

uniplot is cool. I wish subplots were a thing. And I suppose they could be, by writing to a file, then sort of interleaving them...

misc

Some of my old .gpx files have some pretty funky characteristcs. There's a few^[8] with negative time steps in them.

There are many instances of a single .gpx file holding two short rides, separated by a week or more, that end up greatly exaggerating the duration.

I'm manually dealing with these issues, as that is likely the quicker thing to do.

Stop detection

It is a tricky beast. I'm using movingpandas and my current definition of stopped is: spending two minutes within a 50 m radius. Typing that there, it feels wrong. But it's close enough. Ish. There are some instances, where it doesn't clock a stop that is^[9] & some where it registers a stop that isn't.^[10]

Who cares? I'm having fun.

footnotes

thank you stackoverflow (probably) ↩︎
both the duckdb CLI and the python API ↩︎
currently just two ↩︎
probably won't ↩︎
there are many posts dedicated to this, and many of them are a bit sloppy, if you catch my drift ↩︎
I was trying to see if I could use mapscii and then pipe in the bounding box from that... ↩︎
based on little more than a weak hunch ↩︎
19 ↩︎
like turning off the recording device whilst having a picnic, turning it back on, and moving > 50 m before signal is reacquired ↩︎
pushing a heavy bike up a hill ↩︎

winter olympics

tlohde — Sun, 08 Feb 2026 10:41:00 GMT

Some thoughts having watched a bit of the coverage.^[1]

ice hockey

What a bonkers sport. I love it. I wonder how far the puck travels over the course of a single game? I like that they can go behind the goal. The goal appears to be very small. Quite how the players (and camera operators) can track the puck during a goal-proximate scrap is beyond me.^[2]

big air

It's all got a bit too Cool Boarders. So much so that it's lost its appeal. Mighty impressive nonetheless.

figure skating

I'd like to know^[3] more about the scoring system. I struggle with the apparent precision^[4] that comes from what is surely a subjective assessment. I like how not gurning or visibly straining whilst holding your heel behind your head and spinning on the spot^[5] seems to a skill in itself.

downhill skiing

So. Fast. Thighs of steel. Casually jumping 40+ m at 110+ km/h. Whoa. And the margins⸺mere fractions a second, often less,^[6] between competitors over a ~90 second course⸺are tight. And that these differences manifest when skiers are going one-at-a-time. The following drone shots are sometimes great, but having to hear the drone whining in many other shots is slightly annoying. L. Vonn from the USA just crashed and ouch.

speed skating

The slippery velodrome. So cool. Hand nicely tucked behind the back, sometimes held in place with a little bit of rope. I like to think that in another life I could have been a distinctly mediocre speed skater.

coverage

It's an impressive feat. Well done to all the tech folk making it happen. BBC iPlayer just works.

footnotes

yes, it's only day 2 ↩︎
perhaps they can't? ↩︎
but not enough to actively go and look it up ↩︎
2 d.p. ↩︎
a graphic with the rpm would be nice ↩︎
just saw a german athlete finish 0.04 seconds behind first place - missed the name because I was writing this ↩︎

trackly

tlohde — Sat, 07 Feb 2026 14:13:00 GMT

A while ago I listed some of my works in progress. Last week I unpaused one of them (again). Namely, making a database and interface for interacting with all of my running, cycling and hiking .gpx and .fit files. It feels like quite a big job. So I am going to endeavour to break it into small(ish), manageable(ish) chunks.

constraints

it won't be on the internet^[1]
- Local is fine
it wont't have the ability to auto-magically sync^[2]
- Manual ~~will have to do~~ is fine^[3]
it won't neccessarily handle all of the data that my gps device captures
- I'm ok not knowing what my heart rate was at 19:33:10 (BST) on the 22nd August 2019^[4]

functionality

ingest my archive of several thousand .gpx & .fit files
add new files as and when
display an overview of a given ride
search for tracks by date/time & by location
display a heatmap sort of thing
generate summary statistics and visualizations
easily queryable

interface

A graphical interface is, I think, beyond my skillset. Instead I'm opting for a command-line interface (CLI). A text-based user interface (TUI) would be nice, but that too might be a stretch.

Aim low.

tools

python because I know how to use it
- with help from geopandas, shapely & movingpandas (maybe)
duckdb because I want to learn how to use it
- with it's SPATIAL extension
uniplot because it looks like a good candidate for making nice plots in the terminal

The above will (& and some others, no doubt, at some point) will hande the functionality. And the below will help with the interface.

typer because it seems like a good option for making a CLI; it handily makes --help documentation, and allows for fancy things like auto-complete
poetry for bundling it all up into a package, whilst also managing dependencies

Many of these things are new to me.

current status

⛶↗ Fig 0: trackly so far. much still to do.

footnotes

although the free tier of MotherDuck looks like it could work... ↩︎
but if I pay close attention to what garmindb does, & how it does it, maybe sync is possible ↩︎
will have to do ↩︎
178 bpm, thanks for asking ↩︎

1 × 4⅓

tlohde — Sat, 31 Jan 2026 22:51:00 GMT

What happened^[1] over the last four and a bit weeks?

I started doing a bit more exercise after a too long hiatus.

A friend came to stay and made some ramen and it is my new favourite thing to eat. I had it for lunch, and will be having some leftovers shortly. Actually, that's not true, my new favourite thing to eat is this peanut rayu,^[2] which I'm greedily adding to the ramen.

The dog got spooked by some other dogs and bolted home⸺including several busy-ish road crossings⸺and her behaviour has been a bit off ever since. We're working on it.

I read a bit more than usual; climbed about as much as usual; and ate a fair bit less than usual.

exercise

cycling

My partner, somewhat impulsively and extremely generously, gifted me a turbo-trainer.^[3] It came with a two-month free subscription to the fancy online cycling world, which I have opinions about. It's a bit silly, and grossly over-priced. That's the main thrust of my opinion. There's more, but I shalln't go on.^[4] I've done ten "rides" on it so far. An FTP test^[5]; a few endurance sessions; and a sweet-spot session. Never more than a hour. When winter gives way to spring and I do venture outside, I will, hopefully, not feel too slow and rusty.

Cycling is good.

running

Nine runs. Tight calves after each of them.^[6] Nowhere exciting, just back and forth along the slightly boring^[7] strech of coastline. Some of the runs have been with the dog. She makes it look easy. Most of these were < 4 km; all were < 9 km. Some longer(ish) ~threshold(ish) intervals on one of them; and shorter snappier intervals on another.^[8]

Running is good.

climbing

I am grateful for the bouldering wall that's a ~10 minute walk away. I've been a regular since it opened nearly two years ago and I am beginning to get to know a few other regulars. Additionally, a friend from my PhD programme also climbs there, so we tend to climb together once per week. Friends are nice.^[9] The gym doesn't do grades,^[10] just colours. For a good while my level was most-pinks-and-maybe-a-red-on-a-good-day, recently however, I've stepped up a bit and am now more of a more-reds-than-not-and-a-white-if-it-suits-me. I'm still not sure what my style is. I also got some new shoes^[11], and I am a little bit annoyed at how much difference they make. I want climbing to be free from the tech & gear that sometimes makes cycling^[12] annoying. Anyway, progress is nice. I haven't been on the end of a rope for a while, but I'm scheduled to do so tomorrow.

Climbing is good.

losing

A, not wholly unintended, consequence of picking up running and cycling again is that I have lost some weight. Over the last two years^[13] my weight increased by ~15%. And I felt it. In four and a bit weeks I've dropped half of what I'd gained, and I feel a better for it. My "strategy" has been to stop inhaling biscuits by the packet;^[14] cutting out sweet things entirely(ish); and not snacking between meals. This reduction in inputs, coupled with the above exercise, seems to be working.

elsewhere

The elsewhere page doesn't get populated as often as I mean to, so here's a big ol' link dump.^[15]

minifying those css & js bundles?
scour, for scouring the web for interesting things
how to draw mountains by Surprised Eel Maps. See also: mountains on academic maps
model collapse
RSS.social
a podcast episode: Your Digital Footprint Reveals More Than You Think
a year in review
some cheerful climate news: peak glacier extinction. "...with up to ~4000 glaciers vanishing annually." Fuck.,
project euler
focus stacking for macro photography nerds
an in-browser GIS that can handle big point datasets
a thing by Ruth Pozuelo on all the data a garmin watch gathers, but that I can't find a link to anymore
running jupyter notebooks in QGIS
on the probelms with github's monopoly
one year in one image
a nice made-with-11ty-blog
an experiment in natural language parsing and play
fit any dataset with a single parameter
the stunning entries to the Competition in a Can
good review of a Nüborn
so it wasn't just me who didn't get to do fieldword
exams in the age of AI
kitchen slide rule
a how-to backlinks in 11ty that i think i can follow
phantom obligation and why fraidycat is a good rss reader
some overpass resources: overpass-doc; learn overpass; postpass

the post's postscript

last year

Last year sucked. For the most part.

Granted, there were some good things:

re-learning how to develop and print my own B&W images 🡕, 🡕 & 🡕
topping Cima Presanella
doing a tiny bit of climbing outside
a three-day hike from Corrour around Loch Treig and the surrounding Munros
participating in the #30DayMapChallenge again (see the gallery)

Hopefully twenty-twenty-six will be less sucky.

thirteen what? thirteen thirds.

The cadence of Weeknotes™ is too onerous,^[16] so, allow me to introduce the rational (that's a joke) modification to this: thirteen thirds, or 4⅓, or 13/3.

I will endeavour to (i might) write a little what-i've-been-doing every ~~four and a third weeks~~ month. These posts will serve as (a) a memory aide for future me; (b) something that might keep me accountable to something or something like that.

footnotes

a non-exhaustive, prone to the spotlight effect, biased sample ↩︎
which, according to the website, is "inspired by the Japanese condiment Taberu Rayu (食べるラー油)" ↩︎
i'm still not really cycling outside, other than for getting places, on the rare occassion i gotta get places ↩︎
when the subscription runs out, I will move over to the much more affordable icTrainer ↩︎
219 W, thanks for asking ↩︎
a function of being a forefoot striker ↩︎
it's nice, but, I'm bored of it, because it's flat ↩︎
i am currently capable of holding my 5 km PB pace for ~300 m. there's work to do, and i feel reasonably motivated to do it ↩︎
i find socialising pretty hard, and don't tend to miss it when i'm not doing it. but, i am reasonably confident that i do benefit from social interaction (even if it pains me to admit it) ↩︎
for which i am grateful ↩︎
much stiffer than the old pair, with a more defined inside-edge, and a less baggy heel ↩︎
cyclists, more like ↩︎
...of general inactivity and at times deep depression ↩︎
something I am ~~very good at~~ guilty of ↩︎
some of these i've opened, and will close having never read them. that's okay ↩︎
i tried last year, with the intention of posting them with a year's delay. i made it to week 11 before giving up for reasons, and having just skimmed a few, I shalln't be posting them ↩︎

process

tlohde — Sun, 23 Nov 2025 20:09:00 GMT

For the third year I am participating in the #30DayMapChallenge. Creating a map per day for the whole of November is challenging. The challenge is in finding the sweet spot between doable,^[1] and worth doing.

Worth is a moving target. If I learn something new—a technique, a new-to-me matplotlib feature, anything in Inkscape, or that Barnes Ice Cap flows quite slowly—it is worth it. If the output looks a little bit better than ok-ish,^[2] it is worth it. If a few strangers on the internet appreciate it^[3] and enjoy it, it is worth it.

Anyway, I've already made a few^[4] this year, and the prompt for day 23 (today) is:

Process - Show how you make a map. This could be a tutorial, a step-by-step graphic, a blog post, a video, or a screenshot of your work environment. Combine it with a map from another day!

process

It's a delightfully simple process. Refined over time.

have a look

unsurprisingly

The way the process took shape today involved several abandonned ideas. And making that flowchart involved an involuntary and slightly tedious trip down a rabbit hole.

I nearly ended up in the quit box a few times today.

I'll spare you the details. But just know, there are reasons why the diagram isn't nicely displayed on this page in a little interactive window that you can pan and zoom around. Ugh.

footnotes

within the time constraints ↩︎
also a moving target ↩︎
ahh, good ol' external validation ↩︎
22 but who's counting? ↩︎

metaphor

tlohde — Thu, 06 Nov 2025 13:18:00 GMT

I have spent a chunk of time in therapy.

Often, when trying to explain my thought processes, I gravitate towards metaphors that have their roots in a domain in which I am more comfortable: physics & maths & earth science. This means I have found myself explaining the inverse-square law, or the geologic principle of superposition, to the person in the chair opposite in order to help them understand me.

I doubt I'm the only one. And this makes me curious as to what other science-y metaphors, however tenuous, might have been / could be used.

Additionally, I wonder there is any value in cataloguing these^[1]?

for example

Maybe you behave like an ice-marginal lake, filling up until you drain catastrophically.

Instead getting angier at a linear rate, a logistic model might be more appropriate at representing the path between not angry and angry.

Sometimes you might wish your springs (strategies for coping) were joined in parallel rather than series.

Perhaps you woke up feeling like a double compound pendulum, which means, for some reason, that if you do erupt today it'll be more effusive.

Or regelation might aptly describe your response to pressure.

Do you only make covalent bonds?

When navigating life's difficulties do you keep forgetting to account for magnetic declination?

a cursory search

A quick search^[2] for therapy metaphors throws up some research on the efficacy of metaphors; the difference between patient-led and therapist-led metaphors^[3]; and a few .pdfs containing some common and clichéd metaphors^[4]. However, I could not find, unsurprisingly, a library of nerdy metaphors. I want something that would only make sense to a computational chemist, or a string theorist, or a biophysicist. I want to hear about how it was genuinely useful to think about your relationships by looking at them through the lens of lenses: diffraction and refraction.

I would like to low-key curate a collection of these. If you feel comfortable sharing some examples, I would love to hear them - so do get in touch.

footnotes

and delivering them to therapy practitioners ↩︎
that is limited by no longer having institutional access - ugh ↩︎
on skim-reading that, my dissatisfcation with CBT made a bit more sense: "CBT-therapists seemed more focused on therapist-generated metaphors" ↩︎
a life raft; a train going through a tunnel etc... ↩︎

speed climbing

tlohde — Mon, 27 Oct 2025 18:36:00 GMT

Whilst I can appreciate the strength and technique, I don't find speed climbing particularly captivating to watch. In fact, I think it's quite dull. The route never changes and each race is over in five seconds. To me, it feels more like a muscle memory competition.

Having just watched the first three rounds of the the Rockmaster 2025 | Lead Duel, I am convinced that this is what speed climbing should be.

Climbing fast. On lead.