Modelled magnetic field from overhead power lines, against DSA's 0.4 µT investigation level
power_line_field15 fieldsNot in the demo
Available with: bought bundle or agreed plan (all fields) · Pricing
What this does not say
Quoted verbatim from the section’s warnings field, exactly as the API returns it. They are not translated: a translation would show something other than what your response actually contains.
- Estimate, not a measurement: the current on a line is not published and is unknown here. The field is computed for an ASSUMED load per voltage class (field_typical_ut for a typical annual mean, field_high_load_ut for a high load); the real field can be lower or higher, and only a measurement over time says what it is.
- Method emf-flat3-v1: each NVE overhead line within 300 m is modelled as a balanced three-phase line with its conductors side by side at a typical height and spacing for its voltage class, and the field 1 m above ground at the address point's horizontal distance is computed with Biot-Savart (inputs lists every assumed spacing, height and current). The largest single-line figure is served; fields of separate lines are not added because their phases are unknown.
- above_investigation_level_* compares the figure with 0.4 µT, the annual-mean level at which DSA asks for an investigation of measures when new homes, schools or kindergartens are planned near power lines. It is a planning trigger, not a health limit (the ICNIRP public reference level is 200 µT). A line of unknown voltage within 300 m leaves a false flag null.
- The NVE dataset holds the regional and central grid: local distribution lines (22 kV and below), cables in the ground, transformers and wiring inside buildings are not included, and they are often the larger source indoors. lines_within_300m 0 means no mapped line within 300 m: the flags are false for the mapped lines and the field is null, not zero.
- Licence: NVE Nettanlegg via Geonorge, NLOD. Attribution: NVE.
- validation lists each figure the model is checked by, against the reference named in it. value null with status not_yet_computed means the check has not been run on the data yet; it is not a pass.
Fields
5 of 15 fields are value fields — the ones that decide whether a record actually says anything. The rest are context: identifiers, codes and timestamps.
| Field | Type | Role |
|---|---|---|
| field_typical_ut | number | null | value |
| field_high_load_ut | number | null | value |
| above_investigation_level_typical | boolean | null | value |
| above_investigation_level_high_load | boolean | null | value |
| dominant_line_voltage_kv | number | null | context |
| dominant_line_distance_m | integer | null (m) | context |
| nearest_line_distance_m | integer | null (m) | value |
| nearest_line_voltage_kv | number | null | context |
| lines_within_300m | integer | null | context |
| lines_unknown_voltage | integer | null | context |
| method | string | null | context |
| method_version | string | null | context |
| inputs | object | null | context |
| validation | array<object> | null | context |
| computed_at | string | null | context |
Fetch this section
Send the key in the X-API-Key header. The section can be fetched with the rest of the address, or on its own with pagination.
curl --fail-with-body --silent --show-error \ -H "X-API-Key: $APPROACH_API_KEY" \ 'https://api.approach.no/api/v1/addresses/285717643?include=power_line_field' # paginated, one section at a time curl --fail-with-body --silent --show-error \ -H "X-API-Key: $APPROACH_API_KEY" \ 'https://api.approach.no/api/v1/addresses/285717643/sections/power_line_field?limit=25'
Why it cannot be tried here
This section is not part of the public demo projection. That is a licensing and privacy decision, not a sign the data is missing: it is served to customers granted the section.