Frequently Asked Questions

GPSSample is an offline-capable app that allows for collecting geolocated information about a group (e.g., a village), sampling from a set of units (e.g., households) in the field without external software, and navigating back to the sampled units for further data collection in a survey app (e.g., ODK, Kobo, and Ona). 

Yes, GPSSample is free to download and use.

Sampling takes less time. GPSSample can be used to visit every household in the selected enumeration areas marking key questions and to track progress. GPSSample provides a map-based interface with color coded complete / incomplete households that many survey design programs don't have. Listing every household in the selected enumeration areas ensures that each household has the same probability of being selected.

GPSSample can be used for cluster sampling, simple random sampling, stratified sampling, and subset sampling. 

GPSSample runs on Android mobile devices version 8+, and a magnetometer (internal compass hardware) is highly recommended for directions to sampled households. Most use cases to date have used Android mobile devices 10+.

GPSSample allows for collecting gps coordinates, photos, text, date, and basic categorical or numeric information about the units for screening purposes. Single and multi-select questions can be asked.

GPSSample can capture information about landmarks and other local features to assist with navigating to sampled households, distinguishing study boundaries and situational awareness.

GPSSample uses local only hotspot Wi-Fi technology to send files and data between supervisors’ and field teams’ devices. This does not require an internet connection. 

Yes, export the household dataset as a point geoJSON dataset with those linked features. For structures with multiple households, each household should be a point. The study administrator can add cluster boundaries first and then the household geoJSON file and select any linked features to bring into the study. When listing, teams can view the linked features for each household.

GPSSample protects all data using strong encryption compliant with HIPAA requirements. 

GPSSample configuration files and image files (encrypted JSONs) can be exported from GPSSample, downloaded on a computer, and extracted using the GPSSample Decoder. The GPSSample Decoder produces a Microsoft Excel workbook, image files, and a GPX file. 

GPSSample users can select the Mapbox mapping engine or the OpenStreetMap mapping engine. If the Mapbox engine is selected, the GPSSample administrator can select either the Streets or the Satellite view.

OpenStreetMap background tiles can be transferred to the devices via internet directly in the GPSSample app. This community created data is opensource.

Mapbox background tiles (Streets or Satellite Views) can be transferred to the devices via internet direct download in the GPSSample app. 

It is also possible to add your own imagery for an area. Create mbtiles and add these to the configuration as an administrator. 

GPSSample links with ODK Collect, Kobo Toolbox, and Ona. It may link with additional survey tools using XLS Forms, but our development team has not tested other linkages.

GPSSample is not a survey app.  GPSSample facilitates the enumeration and sampling of a study area and links to and opens other survey apps such as ODK Collect, Kobo Toolbox, or Ona to conduct a household survey once the sampling has been completed. 

No, not yet. We focused development efforts on creating GPSSample for Android devices as these are widely available and affordable worldwide. Please reach out to the development team if you want to work on GPSSample code for Apple devices or financially invest in this development. 

Task Force for Global Health: Russell Mitchell, Clara Burgert

U.S. Centers for Disease Control and Prevention: Amber Dismer (*Lead), Joel Adegoke, Louie Rosencrans, Ben Nygren

GPSSample was developed by the Georgia Tech Research Institute (GTRI) with technical input from staff at the U.S. Centers for Disease Control and Prevention (CDC). GPSSample is not an official CDC product. GPSSample training videos and website were developed in partnership with BCL and funding support from the Task Force for Global Health through a cooperative agreement with the CDC.

GTRI: Victoria Razin (*Lead), Megan Denham (*Lead), Russell Mitchell, Brian Parise

CDC: Amber Dismer (*Lead), Joel Adegoke, Louie Rosencrans, Ben Nygren, Amy Lang, and Monica Shah

Translation reviews of the GPSSample app and materials:

• Russian: Mariya Galtser

• French: Maria de Arenas, MFD Language Solutions

• Spanish: Maria de Arenas, MFD Language Solutions

• Bahasa: Adi H. Santoso, AHS Co.

• Persian and Pashto: Razia Mahmodi

GPSSample Testers: 

• Zahin Hossain

• Suhas "Su" Das

GPSSample code and repository reviews were conducted by Codeando México

(2026). GPSSample (Version 2.2.1) [Mobile app].  App Store. https://play.google.com/store/apps/details?id=edu.gtri.gpssample&pcampaignid=web_share.