World Meteorological Organization |
Date: 2026-05-07 |
Version: 0.1 |
Document status: DRAFT |
Document location: https://wmo-im.github.io/first-mile-guide/first-mile-guide/first-mile-guide-DRAFT.html |
Standing Committee on Information Management and Technology (SC-IMT)[1] |
Commission for Observation, Infrastructure and Information Systems (INFCOM)[2] |
Copyright © 2025 World Meteorological Organization (WMO) |
- 1. Scope
- 2. Conformance
- 3. Normative references
- 4. Terms, definitions and abbreviations
- 5. Conventions
- 6. Overview (informative)
- 7. Data model
- 8. Standard name binding
- 9. Protocol binding
- 10. Data sender
- 11. Data receiver (structure TBD)
10. Data sender
10.1. Metadata publication
A key feature of the First Mile Format, is the structured inclusion of metadata. This enables
Benefit |
Definition |
Required in implementation |
Machine Translation |
Received data can be correctly assigned to observations in database without human interpretation/intervention |
Standard Names |
Stranger Interpretation |
Siting (particularly location and height of observations) and equipment can be deduced from data, enabling assessment of observation quality without access to other information |
Location, URL (for additional information) |
Efficient Communication |
Metadata is not included in every message (reducing bandwidth requirements), only to ensure efficient processing by the Receiver |
Transmission Triggers |
10.1.1. Mandatory fields
To enable evolution of the First Mile Standard, while maximising backward compatability, the Protobuf REQUIRED keyword is not used. However, omission of key values can render the other included information unusable as it is ambiguous as to how it is related to the other content.
Message |
Field |
Justification |
HostDevice |
name |
Enables the identification of the end node |
ObserverDevice |
id |
Enables parameters (observation data) to be matched to the sensing/observing/measuring device |
ParameterDefinition |
id |
Enables content from Data messages to be interpreted |
Parameter |
unit |
Critical to hub interpretation of received data |
Parameter |
DeviceRef |
Enables sensors/observers to be matched to their data |
If machine to machine translation is expected, then the following following additional fields must be included
Message |
Field |
Justification |
Parameter |
standardNames |
Enables machine to machine translation of definition, irrespective of parameter name |
Parameter |
CellMethod |
If any data processing is done at the edge, this enables for example the mean and standard deviation to be differentiated (as they will have the same standardNames, units) |