Building-level ground subsidence from InSAR (vertical velocity and differential settlement)

ground_subsidence18 fieldsNot in the demo

Source: Approach model over NGU InSAR Norway (Sentinel-1) and building footprints
Geography: The address point
Reported stale after: 120 days
Access: Requires an API key granted this section
Contract version: 1
In packages: models

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 survey or a geotechnical assessment: velocities of radar reflectors (roofs, walls, ground) within the building footprint plus 20 m, as a trend over the InSAR measurement period (measurement_from to measurement_to), relative to NGU's local reference per processing tile. It does not say the building is damaged or will be.
Method insar-building-v1. vertical_mm_per_year is the median per-point vertical velocity, negative = moving down. With geometry_mode asc_desc the ascending and descending tracks are combined into east and vertical velocity (north neglected); with los_only each point's line-of-sight velocity is divided by its upward component, which assumes purely vertical movement and is wrong where the ground moves sideways or down a slope. settlement_p90_mm_per_year is the 90th percentile of settlement (positive = going down). differential_mm_per_year_per_10m is the tilt of a robust (Tukey biweight) plane fitted to the points, per 10 m: uneven settlement, the part that cracks foundations.
Fewer than 5 usable points (los_up at least 0.3, coherence at least 0.5) leaves every figure and the class null; points_used says how many were found. Roof and ground reflectors are mixed, so a roof that moves with temperature or a settling terrace can dominate a small sample. No record means the kommune's InSAR points are not loaded or the pipeline has not reached it; absence is not stability.
subsidence_class: attention when settlement is at least 5 mm/yr, settlement_p90 at least 8 mm/yr or differential at least 1.0 mm/yr per 10 m; stable when settlement is under 2 mm/yr and differential under 0.5 mm/yr per 10 m (about the noise level of the product); slow otherwise. These are Approach screening thresholds, not a standard.
Footprints: footprint_source names the outline used. 'osm' is an OpenStreetMap outline matched to the Matrikkel building number (ODbL, © OpenStreetMap contributors); 'address_point' means no outline was held and a 20 m disc around the address point was used. FKB building outlines are not used.
Licence: NLOD 2.0 (Norwegian Licence for Open Government Data), stated by NGU on https://insar.ngu.no/. The service contains modified Copernicus Sentinel data. Attribution: Geological Survey of Norway (NGU), InSAR Norway, with NORCE, NVE and the Norwegian Space Agency.
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 18 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
vertical_mm_per_year	number \| null (årstall)	value
settlement_p90_mm_per_year	number \| null (årstall)	value
differential_mm_per_year_per_10m	number \| null	value
subsidence_class	string \| null	value
points_used	integer \| null	value
datasets_used	integer \| null	context
geometry_mode	string \| null	context
east_mm_per_year	number \| null (årstall)	context
footprint_source	string \| null	context
zone_area_m2	integer \| null (m2)	context
measurement_from	string \| null	context
measurement_to	string \| null	context
insar_release	string \| 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=ground_subsidence'

# 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/ground_subsidence?limit=25'

Why it cannot be tried here

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