HintRadius

Control the search radius around hintPosition or geoHint to tune the localization search scope

Overview

hintRadius sets the search radius, in meters, that the VPS uses around a spatial hint. When your localization query includes a hintPosition or a geoHint, the retrieval phase only searches the portion of the map within hintRadius meters of that point. The default is 25 m, and the value can range from 5 to 100.

A smaller radius gives faster queries and fewer mismatches in visually similar areas, but requires a more accurate prior. A larger radius is more forgiving when the hint itself is uncertain.

hintRadius only applies when hintPosition or geoHint is provided in the same query. On its own it has no reference point and no effect.

How It Works

Localization runs in two phases: image retrieval first, then pose estimation. Spatial hints narrow the retrieval phase, and hintRadius controls how aggressively:

1. The hint (hintPosition in map-local coordinates, or geoHint converted from GPS) defines a center point.

2. Only the map portion within hintRadius meters of that point is kept as the search area.

3. Visual matching then runs against the selected map zone only.

Only the map zone within hintRadius of the hint point is searched; the rest of the map is skipped.

If use2DFiltering is enabled with a geoHint, the radius check ignores the Y-axis (altitude) and uses only horizontal distance (X and Z).

Parameter Format

Endpoint type	Format	Example
JSON body (/vps/map/query)	Number	"hintRadius": 15
Form-data (/vps/map/query-form, /vps/map/multi-image-query)	Numeric string	"hintRadius": "15"

Range	Default
5–100 m	25 m

Values outside the range are clamped to 5–100 by the SDKs. Works for both single Maps and MapSets.

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Choosing a Radius

Match the radius to the accuracy of whatever produced the hint:

Hint source	Suggested radius
Previous localization result (device tracking)	5–15 m
QR code or known start point	5–10 m
BLE beacon / WiFi positioning	10–25 m
Outdoor GPS (geoHint)	25–50 m
Low-accuracy GPS (urban canyon, near windows)	50–100 m

If localization starts failing with a tight radius, the hint is probably drifting outside the search area: widen the radius or refresh the hint.

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Examples

// Tight radius around a previous localization result (JSON body)
{
  "hintPosition": [12.5, 2.0, -7.3],
  "hintRadius": 10
}

// GPS hint with a wider radius and 2D filtering (JSON body)
{
  "geoHint": [37.7749, -122.4194, 10.0],
  "hintRadius": 50,
  "use2DFiltering": true
}

// Form-data endpoint, pass as strings
"hintPosition": "[12.5, 2.0, -7.3]"
"hintRadius": "10"

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SDK Support

hintRadius is exposed in all MultiSet SDKs alongside the hint parameters:

• Unity SDK / Quest SDK: hintRadius (int) on MapLocalizationManager and SingleFrameLocalizationManager

• Android Native: LocalizationConfig.hintRadius

• iOS Native: MultisetConfig hint settings

• WebXR SDK: hintRadius in the localization options

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Best Practices

• Always pair hintRadius with hintPosition or geoHint. Sent alone, it is ignored by the server, and some SDKs skip sending it entirely.

• Start with the default 25 m and tighten it only once your hint source has proven reliable.

• Update the hint frequently when the user is moving, a stale hint with a tight radius can exclude the user's true position from the search area.

• For multi-floor buildings, combine with hintFloorHeight to constrain the vertical range, since a 25 m sphere can span several floors.

• To read map-local coordinates for hintPosition directly off the mesh, see Find Hint Coordinates.