Four things asked for in turn, landing together because they run through the
same files.
THE MAPS. The tiles were already cached and always had been -- a second
evening on the same view was measured at nought network requests -- but the
work done on them was not. Every window open decoded forty PNGs and resampled
a megapixel and a half into this program's own projection, for an answer that
cannot have changed, because a coastline does not move. The finished map is
kept beside the tiles now: 0.61 seconds become 0.01, byte for byte identical,
two hundred kilobytes a view. Both windows and both kinds of still picture get
it, all four reaching the ground through one function. A map with squares
missing is deliberately not kept, since caching a hole would keep it for a
month and the point of calling a partial map provisional is that it is asked
for again. And because this adds a disk consumer, the whole cache is now
pruned to four hundred megabytes, least recently *used* first: a tile fetched a
year ago and looked at last night is the receiver's own neighbourhood, and
discarding that to keep last week's holiday is the wrong way round.
THE LOOKUPS. APRS and FT8 now ask who each station is licensed to. Every
other mode that hears a callsign already did -- speech transcripts, Morse
idents, the recording browser -- and all five resolve through one file, so a
callsign heard on two bands is asked about once. The rules for finding the
licensed callsign inside a heard one are now in one place rather than per band,
because getting them wrong is silent: a register asked about W1AW-9 returns
nothing, which looks exactly like a station that is not licensed. An SSID, a
rover suffix, a guest prefix, a digipeater alias and an unspelled hash all come
off or are refused.
The bug worth recording is that the first cut of this did the lookups and threw
them away. The book has to be told to save and was not, so every evening would
have asked the register about the same net again -- which is the one thing
caching them was for, and is invisible from inside a single run because the
answers are all in memory while it lasts. Caught by looking at the file on
disk rather than at the display. There is a test for each side of it now, and a
register of which modules resolve callsigns at all, which fails when a new one
starts so that somebody has to decide whether it should.
THE REGISTER. c in saunterbrowse opens everything ever looked up: sixty-odd
callsigns and sixteen hundred aircraft here, every field of each in two columns
because a licence has a dozen and a screen is wider than it is tall. tab
switches, / searches every field rather than the name -- the question is
usually "who was in Arizona" rather than "which callsign" -- and g opens the
place in a browser. Only the coordinates go into that link: a map does not
need to be told whose licence it is looking at, and the link is the one part of
this that leaves the machine. A headless box, which is the normal case for a
receiver, gets the coordinates printed instead. Callsigns no register could
place are kept rather than dropped, because "asked about, and in no register
reachable from here" is a fact about a station.
THE FRONT OF IT. A title screen for each program: five rows of blocks cut by
hand, a figlet dependency to draw eleven letters being the largest thing that
would then be in the requirements, coloured blue to red across the width, which
is the ramp every waterfall here already uses because it is what a spectrum
looks like. The interesting part is where it does not appear -- everything
here can be piped into something else and a banner in the middle of that is
corruption rather than decoration, so anything that is not a terminal gets
nothing, --help is untouched because it is drawn after parsing, --no-splash
turns it off for a run and BANDSAUNTER_NO_SPLASH=1 for good.
And the address. INSTALL.md said "git clone <the repository>" for a long time:
a placeholder in the first command anybody types, unnoticed because nothing
reads install instructions except somebody installing, who then cannot. It is
filled in, along with the readme, the metadata, both manuals and the Homepage
field of all three packages. The tile server's User-Agent pointed at a topic
listing on somebody else's site for want of an address of its own; the usage
policy of that service asks for one naming the application and giving somewhere
to look it up, so an operator with a question about the traffic has somebody to
ask, and now it gives the real one. Seven tests so the placeholder cannot come
back, verified by putting it back and watching two of them fail.
One thing forced by all this: the keys page in saunterbrowse was exactly as
tall as an eighty-by-twenty-four terminal, so the register entry pushed "q
quit" off the bottom. A test caught it. Home and End have merged into the
Page Up line, which were always the same thought.
THE WINDOWS. They open maximised now, this being a map and the thing anybody
wants more of being map; f goes to true full screen and back, and is written
along the top of the screen because a window with no frame is one somebody has
to know a key to get out of. Maximised rather than frameless by default,
because the title bar is where the band and the frequency are written.
And a map made bigger now gets a sharper map, which it did not. The window
only ever re-examined the ground when the view left the box that had been
fetched, so a window opened at its default size and taken to the whole screen
kept the map it started with until an aircraft wandered far enough to move it
-- on a quiet band, a long time to look at a blurred coastline. Measured
before it was believed: 1100 to 1920 asked for nothing and stretched a
1364-pixel map across 1920, then across 3840. It now compares map pixels per
degree in hand against what the view wants, and asks when it is being blown up
by more than fifteen per cent.
That comparison has to be per degree rather than pixel against pixel, which a
surviving mutation was what established: the fetched box is a quarter wider
than the view, so a map with exactly as many pixels as the window is wide has
only four fifths of them on the screen. The two ways of measuring agree
everywhere except a narrow band, and the realistic case sits inside it. There
is a test pinning that case now. Asking is safe at any size, because the
request is keyed on the window's dimensions: once answered, nothing more is
asked, which is what stops a window larger than the tile budget can cover from
asking all evening.
The braille, while this was open. The banners were blocks in capitals; they
are braille in mixed case, two dots wide and four tall to a character, which is
eight times the detail and is what makes room for two heights of letter at
once -- a five-row block font has no second height to spend, so the name came
out shouted. Two attempts failed first: thin one-dot strokes came out as
confetti, because braille dots render as dots and a one-dot stroke reads as a
dotted line rather than a line. What worked was cutting the font small, at cap
height seven where there is only one way to draw each letter, and doubling it.
Coloured deep blue through cyan to a cool white, which is deliberately not the
waterfall ramp the rest of the program draws in: that one has to run to red
because it stands in for a spectrum, and a title screen stands in for nothing.
One hundred and four new tests. Full suite 2892 passed. Built as
2026-09-24_01.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg
Two faults reported from in front of the window, both of them the map saying
something confidently and wrongly.
Tiles that did not arrive. Resizing the window does not refetch the map: the
window deliberately fetches more world than it shows, so a resize still fits
inside what is in hand and gets stretched to the new size. It refetches when
the view leaves that box, which is what a new station does -- and that fetch
asks a volunteer-funded server for a hundred tiles that have never been on
this disk, all at once, at the sharper zoom the bigger window chose. Some of
them are refused.
What the window did with a refusal was draw it. A tile that never arrived
leaves its square of the canvas black, and black is not a neutral colour
here: the brightness is inverted on the way in, because a printed map is ink
on paper and this picture is the other way round. So the darkest possible
square came out as the brightest thing on the picture, a glowing rectangle
where the map should be. Measured on a reproduction, one missing tile in
eighteen put thirteen thousand pixels at full brightness -- and dragged the
floor of the map's own contrast down to black with it, so thirteen thousand
four hundred and ninety pixels changed in all: the whole map was redrawn
dimmer to make room for a square that was not there. Then it was kept, cached
under the view it was fetched for, until the view moved again.
So the missing squares are asked for again at once, and only those, the rest
being on the disk by then; what is still missing is drawn as bare ground and
left out of the reckoning when the darkest and brightest of the map are worked
out, which puts the same reproduction at two pixels changed rather than
thirteen thousand four hundred and ninety, a hairline where a cell is averaged
over part of a tile and part of nothing; and the map is kept as provisional
rather than as the last word, asked for again half a minute later, four
attempts in all, each retrying its own misses once.
Found while measuring that: the politeness pause between requests was being
paid on every tile, including the ones read straight back off the disk. Two
hundred and twenty tiles at an eighth of a second is twenty-six seconds of
sleeping to redraw a view that was entirely cached, and it would have made
asking again for three missing squares cost the wait for the two hundred that
were not. The constant's own comment already said it should only be paid on a
tile that was not already there. Now it is.
The APRS map's units. Setting imperial changed nothing at all about the
window: the unit it measures in was hardcoded to kilometres, and that one
value drives the ring labels and the scale along the bottom; and --radius was
always read as kilometres, so the rings were not merely mislabelled, they were
at the wrong distance from the flag. A ring is what a distance gets judged
against by eye, and one labelled in a unit it was not drawn in is a wrong
answer given confidently. The aircraft side has done this properly all along
-- a radius read in whatever unit the speeds are in, and no unit suffix on the
setting because the suffix belongs to the other setting -- so this now mirrors
it exactly. At --radius 100 in imperial the outermost ring stands seventy-
five statute miles from the flag and says so, where it used to stand seventy-
five kilometres and say kilometres whatever you had asked for.
Twenty-one new tests against sixteen deliberately broken builds. One
survived, and removing what it broke was the right answer rather than
strengthening a test: a check that the remembered request still matched the
map in hand could not be made to fail, a request for a different view being
taken up only after the slot it guards is already full. The tests do not
trust the drawing to mark its own homework -- the one that matters walks north
from the flag by each ring's radius and measures the great-circle distance
with a haversine written in the test, then checks that against the printed
label. Full suite 2685 passed. Built as 2026-09-21_03.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg
Three things asked for, and a fourth found while doing them.
The map looked like a photograph of a map, and did so twice over. The
window fetched at its own pixel size but for a box a third larger in each
direction -- the margin added to stop the ground blinking -- and then cut
the middle out, so every pixel was enlarged by two thirds. It now asks
for enough pixels to cover the bigger box at the window's own detail.
Underneath that, both the window and the animation took the nearest source
pixel: the tile mosaic is commonly half again the size of the picture, so
most of every tile was thrown away and what survived was the aliasing.
Both now average the source pixels that fall in each output cell, done as
the difference of a running total rather than a loop.
An aircraft that goes quiet now fades instead of vanishing. Taking it off
between one frame and the next says it stopped existing; fading says it
stopped talking, which is what happened. It fades where it was last
actually seen and never along a reckoned track, because the reason for
giving up on it is that where it would be by now is a guess. --fade sets
how long, and it is in the menu. The window has alpha and fades smoothly;
an indexed picture cannot blend, so the animation gained a fourth ramp at
a seventh of full and fades in four steps, which at a second apart reads
as a fade. A trail fades with the aircraft it belongs to, and the box
goes before the symbol does.
The aircraft's country of registration carries a flag now as well as the
two ends of its route, from the register where one answered and from the
address block otherwise.
And the fourth: the window's header counted an aircraft that had gone
quiet as overhead, which was saying more than had been heard.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg
Four things the ADS-B mode was missing, and one it was actively getting
wrong.
The band plan lists 1090 MHz because that is where ADS-B is, so choosing
it from the band plan is the obvious thing to do -- and it records the
bursts as clicks in a WAV file and decodes nothing, silently. Both the
scanner and the menus now say so, before the sweep starts, and name the
mode that does decode it. It is not refused: looking at the raw spectrum
is a fair thing to want.
Menu 5, Aircraft (ADS-B), is the whole mode without a command line. Every
option on one screen with a line saying what it does, ?N for the long
version and the flag it corresponds to, l to listen, m to draw a map from
any log, s to keep the options. The listening and the drawing moved into
bandsaunter/aircraft.py so the menus and the command line run the same
code.
While it listens the screen is a live board: one line per aircraft in the
order first heard, the counter climbing as frames arrive, height coloured
low warm to high cold with an arrow for climb or descent, the age of the
last report going green to red, and the line removed once nothing has been
heard for --hold seconds, everything below moving up. The registers are
asked while it runs, so registration, type, operator and route fill
themselves in as the answers arrive.
--speed-unit knots|mph|kph changes the heading of that board, the speed
beside every aircraft on the map and the speeds in the report, and moves
the distances with it so that one picture never carries two different
miles. The log stays in knots, which is what the aircraft broadcast.
And there is a real map under the flight paths: {z}/{x}/{y} tiles fetched
once, cached in ~/.cache/bandsaunter/tiles, reprojected from Web Mercator
pixel by pixel, inverted and dimmed so the aircraft stay the brightest
thing on the picture. The PNGs are decoded here -- zlib and the five row
filters from the specification, checked byte for byte against Pillow on
real tiles -- so nothing new is depended on. Tiles are cached and never
re-fetched, every request says who is asking, and the attribution is drawn
onto the picture, because a GIF travels without its readme.
conftest now fails any test that reaches for a tile server or a register.
It caught four of these on the way in.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg
The Dust Council