Yinji · GPS Accuracy Spike

Backlog A1 · walk the full Icons day · output feeds content schema Block 2
Ten-minute check — do this first
Walk once around the block before committing three hours. Each step has a pass mark.
  1. Accuracy shows a number under about 30 m outdoors. If it reads 500 m or more you are on a wifi or network location, not GPS — step away from the building and wait.
  2. Walk one block. "Distance moved" must climb. If it stays at 0 m while you walk, the phone is serving a fixed wifi position and the whole walk would be worthless.
  3. Press MARK STOP once (choose "between stops"). A row must appear in the results table.
  4. Lock the phone for 30 seconds, unlock. Fixes should start climbing again within a few seconds.
  5. Reload the page. Your mark must still be there — that proves nothing is lost if the browser reloads mid-walk.
  6. Press Send to server now. The line under the numbers must say "Saved to server" with a time.
  7. Press Copy JSON, then Download. Confirm both actually work now, not after three hours of data.
  8. Note the battery percentage before and after. Multiply by 18 for a rough three-hour cost.
If any step fails, the big walk will waste the morning. Fix it first.
Passed all eight? Press Clear all data and start the real walk clean.
How to do this walk
At every stop
  1. Stand where a traveller would stand — where the view is, where people photograph. Not the centre of the monument.
  2. Pick the stop from the list below.
  3. Press MARK STOP and hold still for the full 10-second countdown.
Mark the Round Tower twice — street level, and the top if you go up. Separate entries; the top is the suspected weak spot.
Leave this running between stops. The continuous log captures street-level accuracy in the narrow stretches, which matters as much as the squares.
Download or copy the JSON before you go home.
Watch spread in the results table — how far the position wandered while you stood still. High accuracy with high spread means the phone is confident and wrong.
Full guide: WALK.md in the repo.
— m
accuracy (68% confidence radius)
latitude—
longitude—
fixes received0
time to first fix—
distance moved0 m
running for0:00
Requesting location…
Stand where a traveller would stand, then hold still for the countdown.
stopacc medbestworstspreadradius
No marks yet.
Continuous log 0
tacclatlng
Data is saved to this browser as you go, and sent to the server every two minutes when there is signal. Download stays as your backup.