Notes

The measurements and validations behind decisions: encoding, power, FROST, QGIS, forecasts, public datasets, validation sites.

• A real station, live: McAllister Farm's SCAN feed

  Build step 7 wants a real device driver before hardware arrives. Q6's Plan B: read a real station's live feed through layer zero, as a node's readings would…

• Draft: comment on OGC SensorThings issue #174

  The posted text differs from the draft below in two ways, both decided at send time:

• How deep the roots are, through a season

  Written 2026-10-13. Two questions: how a well-watered crop's root depth runs with time, and what on a farm shows how deep the roots actually are. The…

• In the soil, besides moisture: temperature, tension, salinity, drainage

  Written 2026-10-12. The soil-moisture probes are in soil sensors; this note is the other things worth putting in the ground, in the order they are worth it to…

• Is public data enough to really test this?

  Researched 2026-10-07, after testing the APIs rather than reading about them.

• Lawn sprinklers: the add-ons, and what each is worth

  A home lawn on an in-ground system usually has a timer, a few zones of spray heads and nothing else. This note asks which small additions to that hardware…

• Our health checks against ISMN's quality flags

  The §9.2 "replay of real recorded field data" that validation-data.md recommended, run for real: layer zero's §4.2 checks over 2,792,596 hourly readings from…

• Q5 measured: which binary encoding

  Run 2026-10-07 with tools/q5_encoding.py. Reproduce with make q5; the operating-point tables with make q5-points.

• Real devices to test against, without owning them

  Written 2026-10-13, from a question: are there sites, vendors' or others', that give free access to hardware's data, so fieldmesh can be tested before a farm…

• Soil moisture sensors to recommend

  Which soil probes a farm on fieldmesh should be pointed to, how each reaches the log, and what fieldmesh's own evidence says about choosing and installing…

• Soil water models: how others do it, and what the simulator takes

  Written 2026-10-16. The soil advisory is backtested on a simulated farm (sim/physics.py), and its results turn on how that soil moves water: on 2026-10-15 the…

• Spikes and jumps on real soil

  Open question Q23 found that §4.2's rate check cannot fire at hourly sampling — it caught none of 1,849 readings ISMN flags as spikes or jumps at the three…

• Sprinklers and drip: the open projects, where they meet this one, and what could flow each way

  Looked at on 2026-10-11. Licences and activity were read from each repository, and every claim about OpenSprinkler's messages from its firmware's source.

• The siting check on real soil

  The §4.1 depth-from-temperature siting check (sdk/siting.py) had only ever met the simulator's heat model. ISMN carries real soil temperature at five depths…

• The soil-moisture advisory's backtests, 2026-10-11 to 2026-10-19

  The record of what the soil-moisture advisory was tried on, on the virtual farm as each day had it, and what each try showed: the tables that once stood in…

• Two real clients, pointed at the HTTP service

  spec §10, VIRTUAL_FARM.md step 7's cheap half. The HTTP layer in server/ was written, tested against 69 of its own tests, and then handed to two clients…

• Validated against FROST-Server

  Run 2026-10-07 against fraunhoferiosb/frost-server:latest with postgis/postgis:16-3.4. Companion to sdk/sensorthings.py.

• Water meters and head flows: the arithmetic of a clogged head

  Saved 2026-10-11. Items 1–3 below were built the same day, as modules/zoneflow; item 4 on 2026-10-12.

• Weather forecasts as input data, and real weather in the virtual farm

  Two additions, built together because each tests the other: layer zero takes weather forecasts as data (Q26), and the virtual farm can live through a real…

• Weather stations to recommend

  Which weather stations a farm on fieldmesh should be pointed to, and the ideas around them: what to measure, where to put it, how to check it, and how it gets…

• What the SensorThings 2.0 draft looks like

  Read Oct 7, 2026, against the editor's rendering of OGC 23-019 and the published 1.1 standard (OGC 18-088). Written to answer one question: what changes for…

• Where a node's battery actually goes

  Run 2026-10-07 with tools/power_budget.py. Reproduce with make power.