This app allows you to take image and measure with low-cost GNSS module (like U-blox GNSS module or E-GNSS from potretudara : http://www.potretudara.com/low-cost-gps-gis/ ). Measured coordinates from low-cost GNSS module are stored to EXIF image metadata in time when you tap the "capture" button. Use this to create your geotagging more precise to sub-meter level. Very useful for census, GIS support, reporting issue, and others. You can still use internal GNSS for geotagging by deactivate BASE