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Urban heat and trees

Urban heat, measured where people live.

Heat is the deadliest weather in many cities, and it is not the same in every street. Street-level temperature and humidity sensors, rooftop references and soil moisture under street trees report to one record the city’s heat plan, health teams and park services all use.

Plan a deploymentHow it worksStation Builder
Industry
Cities
Measurements
5
Sources cited
3
  1. Cities · Urban heat and trees

    Not every street is equally hot

    On a heat-wave night some neighbourhoods stay several degrees warmer than the official station shows, and the people most at risk often live there. Knowing which streets are hottest, and which trees are drying out, lets the city send care, cooling and water where they matter.

  2. What is measured

    Street heat, references and tree soil

    Shielded sensors on lamp posts measure air temperature and humidity at street level across neighbourhoods. Park and rooftop stations give the reference, soil probes in tree pits show which trees are drying out, and satellite thermal images map surface heat across the city.

    Instruments
    Street temperature and humidity · Reference stations · Tree soil probes · Satellite thermal imagery
  3. The base node

    A node that knows a wall from the air

    The gateway’s node checks each street sensor against its neighbours and the park reference, flags one that reads the sun or a wall, computes heat indices and raises heat and tree-drought alerts, signing every value before it leaves. Suspect readings are flagged, never silently dropped.

  4. Radio and links

    LoRaWAN across the neighbourhoods

    Many small battery sensors on lamp posts and in tree pits reach a few gateways on roofs over LoRaWAN, with no cabling. Gateways and park stations reach the city platform over cellular, or the city’s fibre where it runs. Each gateway is supervised.

    Links
    LoRaWAN · Public cellular · Fibre
  5. How it works

    From a hot street to a knock on the door

    On a heat-wave evening, sensors in one neighbourhood stay hot long after sunset. The node computes the heat index and raises an alert for that area; health and social services visit vulnerable residents there first. The record keeps the readings and the response.

  6. From order to operation · Order

    Scope the heat plan

    The scope reads the heat-health action plan, the neighbourhoods and people at risk, the street tree inventory and cooling centres. Nexus Observatory Inc. returns the point plan by neighbourhood, the radio design, the integration with the heat plan and a price per point and per service.

    Plan a deployment
  7. From order to operation · Survey

    Choose posts in the shade of the method

    Crews choose lamp posts in each neighbourhood following urban siting guidance: height, distance from walls and vents, sky view. They pick representative tree pits with the park service, find park and roof reference sites and check gateway coverage. Each candidate is photographed for the design.

  8. From order to operation · Permits

    Posts, trees and data

    Sensors on lamp posts and in tree pits need the owners’ consent and follow street works rules. Sharing data with health agencies is agreed in writing. Every consent is kept with the point it covers. Residents are told what the sensors measure, and the park service agrees every probe placed in a tree pit.

  9. From order to operation · Build

    Build shielded points

    Temperature and humidity sensors are fitted in radiation shields, soil probes and endpoints are tested together with the gateways and enrolled with their identities. Every point is labelled with its street and post number. Configurations are tested on the bench with the gateway before anything is installed.

    Open the Station Builder
  10. From order to operation · Install

    Install before summer

    Crews mount shielded sensors at the sited height, set soil probes in tree pits at root depth, install reference stations in parks and on roofs and gateways where they see the neighbourhood. Every point is photographed and its siting recorded.

  11. From order to operation · Commission

    Compare with the reference

    Each endpoint proves its identity. Street sensors are compared with a travelling reference and the park station, soil probes with a hand sample, and heat alerts are tested to the heat plan’s contacts before the warm season. Each point joins the map only when its checks pass.

  12. From order to operation · Operate

    Warn, cool and water on evidence

    During heat waves the city sees which neighbourhoods are hottest, health teams reach vulnerable people there first, cooling centres open where needed and park crews water the trees whose soil is driest. Every alert is kept on the record. Each season is reviewed with the record.

  13. From order to operation · Maintain

    Check each spring

    Each spring, shields are cleaned, sensors checked against the travelling reference, batteries changed on plan and soil probes reset after tree works. Every change is recorded, so neighbourhood heat series stay comparable year to year. Spares are kept ready for quick swaps in the warm season.

    Book field services
  14. Data products

    For health teams, parks and planners

    Heat plan coordinators and health teams receive neighbourhood heat maps; health and social services receive heat alerts by area; park and tree services receive tree drought alerts; urban planners receive heat records to place trees, shade and cooling. Each product carries its siting.

    See the data products
  15. Evidence

    Heat measured the right way

    Every reading, alert and response is signed and kept. Street sensors follow WMO guidance for measuring the urban heat island, references follow WMO instrument practice, and alerts support heat-health action plans, so the city can show where heat struck and what it did.

    Drawn against
    WMO-No. 1292 · WMO-No. 8 · WHO heat-health action plans
  16. What you get

    Environmental exposure monitoring for health programmes

    Heat, air and water exposure measurements around facilities and communities; no diagnosis or treatment. Delivered as managed service and data licence, for health authorities, hospital networks, employers. Scale: City to national. Service levels are written as numbers you can measure on your own dashboard.

    Talk to sales
  17. Next step

    Plan urban heat and trees with us

    Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for urban heat and trees. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace.

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01The place and its hazards

Where it runs, and what can go wrong.

Operating contextCities heat up more than their surroundings, and some neighbourhoods far more than others. Heat-health action plans set how warnings and care are organised, trees and green space cool streets if they are watered, and cooling centres must be where they are needed. Official weather stations are sited away from the city’s hottest places.

Hazards

  • Heat illness and deaths among vulnerable people
  • Neighbourhoods much hotter than official stations show
  • Street trees dying in drought
  • Cooling centres in the wrong places
  • Sensors mounted where they read the wall, not the air

02What must be measured

What, where, how often, and under which rules.

Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below.

MeasurementWhereCadenceSources
Air temperature and humidity at street levelSensors on lamp posts across neighbourhoods, sited to urban practiceContinuous12
Reference weatherRooftop and park stationsContinuous2
Tree soil moistureProbes in tree pits and planted bedsSeveral times a day1
Heat-health thresholdsEach warning area, from forecasts and measurementsDaily in the warm season3
Surface temperatureThe whole city, from satellite thermal imageryEach available pass1

03The observation stack

From one base unit to a network.

The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol.

  1. 01

    Base unit

    A street point: a shielded temperature and humidity sensor or a tree soil probe on a LoRaWAN endpoint that signs every value.

    Build a station →
  2. 02

    Site

    A neighbourhood: street points, a park reference station and a gateway on a roof with cellular backhaul.

    Plan a site →
  3. 03

    Fleet

    Every point of a city run as one fleet, with one record.

    Managed offers →
  4. 04

    Network

    Cities, health agencies and meteorological services exchange heat data through open standards.

    The open protocol →
  • 01Compact weather station
  • 02Soil probe
  • 03LPWAN endpoint
  • 04LoRaWAN gateway
  • 05Cellular modem/router
  • 06Battery case
  • 07Pole

Radio and links

LoRaWAN

Many small battery sensors on lamp posts and in tree pits reach a few gateways on roofs, with no cabling.

Radio and links

Public cellular

Gateways and park stations reach the city platform over the public network.

Radio and links

Fibre

Gateways on city buildings use the city’s own fibre where it runs.

Edge computeThe gateway’s node checks each sensor against its neighbours and the park reference, flags sensors in the sun or against a wall, computes heat indices and raises heat and tree-drought alerts.

PowerStreet sensors and soil probes run on batteries for years; gateways on building power.

04How it works

From the instrument to the product.

One observation’s path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks.

Urban heat and trees: data path

– of 07

01 Instruments Measurement with sensor identity andcalibration 02 Field radio 03 Gateway 04 Backhaul 05 Site Consumer inbox deduplicates and applieseach record once into governed data 06 Data store Governed product through API, map orexport, correction-aware 07 Products OGC SensorThings APILoRaWANCommon Alerting Protocol 08 Power and structure Supplies 12 V DC to the field equipment 01 Compact weather station SDI-12 · RS-485 · Ethernet 02 Soil probe SDI-12 · RS-485 · Ethernet 03 LPWAN endpoint Analogue I/O · SDI-12 · RS-485 04 LoRaWAN gateway Ethernet · RF · GNSS antenna 05 Cellular modem/router Ethernet · USB · RS-232 Site MQTT 5 with Sparkplug B Governed data store Versioned, correction-aware Neighbourhood heat maps Heat alerts by area Tree drought alerts Heat records for planning 06 Battery case USB 07 Pole SDI-12 SDI-12 LoRaWAN Ethernet LTE/NR
From the instrument to the published product: each band is a tier, each connector names its interface, and the numbers match the bill of materials. Hover or focus a block to trace its path; scroll or step to follow one observation.
Bill of materials
ItemEquipmentData portsProtocolsPower in
01Compact weather stationAll-in-one or compact station for temperature, humidity, pressure, wind and rain at a site.SDI-12RS-485EthernetSDI-12, Modbus, MQTT 5, OGC SensorThings API12 V DC
02Soil probeProbe for volumetric soil moisture, temperature and conductivity at one or more depths.SDI-12RS-485EthernetSDI-12, Modbus, MQTT 5, OGC SensorThings API12 V DC
03LPWAN endpointBattery-powered endpoint on LoRaWAN, NB-IoT or LTE-M that carries one or more sensors.Analogue I/OSDI-12RS-485LoRaWAN, OMA LwM2M, CoAPInternal battery, Energy harvesting
04LoRaWAN gatewayMulti-channel LoRaWAN gateway that forwards uplinks to a network server and schedules downlinks within duty limits.EthernetRFGNSS antennaLoRaWAN, MQTT 5PoE, 12 V DC
05Cellular modem/routerLTE or NR modem or router that uses a public carrier or private network as backhaul.EthernetUSBRS-2323GPP E-UTRA air interface, 3GPP NR air interface, OMA LwM2M12 V DC, PoE
06Battery casePortable battery pack with DC outputs for field kits.USBModbusAC mains, HV DC, USB PD
07PoleUtility, street or dedicated pole with clamp positions.———

How it scales

01 Instruments Arbitrary qualified sensors and instruments whosemeasurements are ingested with calibration, units,geometry, time, custody and uncertainty. ×n 02 Node The minimum useful deployable unit: server, ruggedappliance, radio node, sensor gateway, satelliteterminal, AI, scientific, vehicle or virtual node. Node Node agent 03 Site The minimum independently operable localgovernance and failure domain: one or more nodesplus local network, identity, policy, evidence,storage, products and operator surfaces.

SITE

Node Node Node ×n 04 Cluster An optional scale or specialisation domain forscheduling, shared storage, accelerators or datalocality.

CLUSTER

×n 05 Fleet Coordinates plans, acknowledgements,convergence evidence, update campaigns andcorrection propagation across nodes and sites.

FLEET

Fleet controller ×n 06 Federation An exchange of products, capabilities, events orwork across approved, independently administeredtrust domains, using explicit trust, policy,data-locality, version and correction contracts.

TRUST DOMAIN

TRUST DOMAIN

TRUST DOMAIN

×n Verifier Applications Data in the field Telemetry Control Data upstream Control Data upstream Control Exchange Evidence Events Exchange
The smallest deployable unit is one node; the same unit is replicated to meet the demand. Nodes form a site, sites may form a cluster, sites and clusters are coordinated as a fleet, and fleets exchange across independently administered trust domains. Each plane is a separate channel with its own open binding.
Data in the field
MQTT 5 with Sparkplug B; connectors for LoRaWAN, OPC UA and instrument buses.
Telemetry
OpenTelemetry OTLP.
Control
TLS 1.3 with mutual authentication; protobuf messages over gRPC or HTTP/2.
Data upstream
At-least-once publication with repeat-safe keys over the control channel or NATS JetStream; QUIC MAY be used on lossy links.
Evidence
DSSE-signed in-toto statements; SLSA provenance; SCITT transparency receipts.
Events
Event envelopes mapped to CloudEvents 1.0; channels described in AsyncAPI 3.
Exchange
OpenAPI 3.1; the OGC API family; SensorThings; STAC; WIS 2.0.

05From order to operation

Every step, from the first call to a running site.

The same crew and the same record carry the work from scope to maintenance.

  1. 01 Order

    Scope the heat plan

    The scope reads the heat-health action plan, the neighbourhoods and people at risk, the street tree inventory and cooling centres. Nexus Observatory Inc. returns the point plan by neighbourhood, the radio design, the integration with the heat plan and a price per point and per service. 3

  2. 02 Survey

    Choose posts in the shade of the method

    Crews choose lamp posts in each neighbourhood following urban siting guidance: height, distance from walls and vents, sky view. They pick representative tree pits with the park service, find park and roof reference sites and check gateway coverage. Each candidate is photographed for the design. 1

  3. 03 Permits

    Posts, trees and data

    Sensors on lamp posts and in tree pits need the owners’ consent and follow street works rules. Sharing data with health agencies is agreed in writing. Every consent is kept with the point it covers. Residents are told what the sensors measure, and the park service agrees every probe placed in a tree pit.

  4. 04 Build

    Build shielded points

    Temperature and humidity sensors are fitted in radiation shields, soil probes and endpoints are tested together with the gateways and enrolled with their identities. Every point is labelled with its street and post number. Configurations are tested on the bench with the gateway before anything is installed.

  5. 05 Install

    Install before summer

    Crews mount shielded sensors at the sited height, set soil probes in tree pits at root depth, install reference stations in parks and on roofs and gateways where they see the neighbourhood. Every point is photographed and its siting recorded.

  6. 06 Commission

    Compare with the reference

    Each endpoint proves its identity. Street sensors are compared with a travelling reference and the park station, soil probes with a hand sample, and heat alerts are tested to the heat plan’s contacts before the warm season. Each point joins the map only when its checks pass.

  7. 07 Operate

    Warn, cool and water on evidence

    During heat waves the city sees which neighbourhoods are hottest, health teams reach vulnerable people there first, cooling centres open where needed and park crews water the trees whose soil is driest. Every alert is kept on the record. Each season is reviewed with the record. 3

  8. 08 Maintain

    Check each spring

    Each spring, shields are cleaned, sensors checked against the travelling reference, batteries changed on plan and soil probes reset after tree works. Every change is recorded, so neighbourhood heat series stay comparable year to year. Spares are kept ready for quick swaps in the warm season.

06Data products and integration

What it delivers, to whom, and into which systems.

Data products

  • Neighbourhood heat mapsHeat plan coordinators and health teams
  • Heat alerts by areaHealth and social services
  • Tree drought alertsPark and tree services
  • Heat records for planningUrban planners

Integration

  • Heat-health action planAlerts by area reach the plan’s coordinators beside the meteorological warnings.
  • Tree managementDrought alerts open watering jobs in the tree inventory.
  • City data platformObservations are served through OGC SensorThings with siting metadata.

Exchanged through OGC SensorThings API, LoRaWAN, Common Alerting Protocol.

07Questions buyers ask

Before you scope it.

Why not use the airport’s station?

It is sited away from the city’s hottest places; street sensors show where people actually are.

Who issues heat warnings?

The meteorological and health authorities; city data shows where to act first.

Do sensors in the sun give wrong numbers?

They are shielded and sited to urban guidance, and the node flags any that read high.

Can we water trees on evidence?

Yes. Soil moisture shows which trees need water first.

08Resources

The sources behind this page.

Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does.

  1. 1Guidance on Measuring, Modelling and Monitoring the Canopy Layer Urban Heat Island (WMO-No. 1292)World Meteorological Organization · 2023
  2. 2Guide to Instruments and Methods of Observation (WMO-No. 8)World Meteorological Organization
  3. 3Heat-health action plans: guidanceWorld Health Organization Regional Office for Europe · 2008

09Related

Use cases and solutions.

Solution

Environmental exposure monitoring for health programmes

Heat, air and water exposure measurements around facilities and communities; no diagnosis or treatment.Solutions for cities →
Solution

Sensing as a Service

Observation networks designed, installed, operated and maintained for a monthly fee: weather, hydromet, air, seismic and environmental stations, with data delivered under a licence.Solutions for cities →
Solution

Municipal sensing and connectivity layers

City-wide LPWAN or private 5G as a shared layer for public sensors and services.Solutions for cities →

10Cities: specialized fields

Other fields of this industry.

Specialized field

Urban air quality

Reference stations and dense sensor networks for particles and gases, with weather to trace sources, calibrated against each other, on cellular and LoRaWAN, for street-level maps people can trust.The full field →
Specialized field

Streets and mobility

Counts of people, bikes and vehicles, speeds, kerb use and junction safety by camera and radar processed at the edge, on private 5G and fibre, so streets are planned on evidence and privacy is kept.The full field →
Specialized field

Public buildings and energy

Energy, heat and water meters, indoor air and comfort in schools, offices and pools, with weather for normalisation, on the buildings’ own networks behind a security gateway.The full field →
Specialized field

Waste and street services

Bin fill levels, collection routes, transfer station gas and weather, on LoRaWAN across the city, so crews empty what is full and the waste record follows from the work.The full field →
Specialized field

Noise and the night-time city

Class 1 noise monitoring at hot spots, event classification at the edge for nightlife, construction and traffic, with weather, on cellular, so complaints are answered with evidence and noise plans work.The full field →

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