Don't be an Earth Hater, use Terra Rater! Terra Rater (TR) is an app that employs the sensors in your Android device to periodically collect data along with a location and time of measurement. When aggregated with other users' measurements across Earth, this data can be used for scientific modeling and/or visualization. TR does not collect any data about the user. TR takes measurements four times per day and the energy used is miniscule. TR is currently a work in progress - for now, only magnetic field detection is enabled. Other sensors in the list are greyed-out but may be enabled in a future update. If you are interested in using this data for a science project or would like to develop a similar, custom app, please don't hesitate to contact me at firstname.lastname@example.org. Thanks for using Terra Rater!