Type 41: GPS Capture — SmartSurvey Docs

Question Type

41 GPS Capture Geo *GPS

CAPI-only type that captures the device GPS coordinates (latitude and longitude) at the point the question is reached in the interview. Coordinates are stored as metadata attached to the submission. When two *GPS questions are placed at different points in the script — typically one at the start and one at the end — the system automatically calculates the distance (in metres) between the two captured locations. This distance is used in geo-validation reports to detect whether the interviewer moved significantly during the interview, which may indicate a data quality issue.

Type ID 41

Directive *GPS

Category Geo

Script Definition

script definition (.q)

-- Single GPS capture: records the interview location at this point in the script.
-- The system automatically calculates the distance between the two points.
*QUESTION Q41 *GPS
Q41. Capture interview location.

Use in Expressions

expressions

-- No scripting expressions are available for *GPS questions.
-- Latitude, longitude, and calculated distance between GPS_START and GPS_END
-- are available as metadata fields in the field audit and geo-validation reports.

*GPS captures two coordinate values — Latitude and Longitude — at the exact moment the question is displayed on the device. Both values are stored as decimal degrees (e.g. Latitude: 23.8103, Longitude: 90.4125 for Dhaka).

Why use two *GPS questions? Placing GPS_START at the beginning and GPS_END at the end of the script allows the system to automatically calculate the straight-line distance (in metres) between the two captured locations. If the distance is large, it indicates the interviewer physically moved during the interview — a potential sign of a fabricated or relocated interview.

The calculated distance between GPS_START and GPS_END is available in the geo-validation report. Set a distance threshold (e.g. flag interviews where distance > 100 metres) to identify suspicious submissions for supervisor review.

GPS capture only functions in CAPI mode. The device location services (GPS) must be enabled and the interviewer must grant location permission to the survey app before the interview begins. Without location access the coordinates will not be captured.

GPS accuracy depends on device hardware and environment. Indoor locations or areas with poor satellite visibility may result in reduced accuracy or no reading. Instruct interviewers to step outside briefly if GPS fails to lock.