Create iOS / Android app and allow offline use. Allow current position to show

We’d like to use labelbox to annote UAV remote sensing imagery. To validate annotation, people in the field have to physically go to the area imaged by the UAV and use image segmentation to draw polygons around objects (eg. crown of an individual plant) and label it (eg identiy it to species). To do so we’d have the UAV orthomosaic basemap as background (WMTS service?). But there might not be any cell reception so we’d need to be able to work offline. Would also be great to show current location (GPS) on the basemap.