How to Prepare and Import Maps for Offline Fieldwork with RockGeo
To use base maps offline in RockGeo, you must import georeferenced spatial files (GeoTIFF raster, tiled MBTiles imagery, GeoPDF survey sheets, or vector Shapefiles) into your project before leaving camp. In the app's map screen, navigate to "Layers > Import Base Map", select the file from device storage, and allow local tile caching. Once in Airplane Mode, your base map remains fully responsive and visible beneath your real-time GNSS location.
Supported spatial formats in RockGeo
The native Android engine supports standard geosciences formats used across academic and commercial sectors:
- MBTiles (.mbtiles): the most performant format for high-resolution satellite imagery and hillshades. It stores multi-level zoom pyramids in an efficient local SQLite container, enabling fluid panning without exhausting device RAM.
- GeoTIFF (.tif / .tiff): the gold standard for georeferenced analytical rasters (drone orthomosaics, multispectral bands, DEM grids, digitized geological folios).
- Shapefile (.shp / .zip): vector overlays for known geological contacts, fault traces, road networks, and concession boundaries.
- GeoPDF (.pdf) & KML/KMZ: official government topographic sheets and traverse planning polygons.
Preparing and optimizing rasters in desktop QGIS
Importing multi-gigabyte uncompressed aerial imagery directly into a smartphone can cause memory stalls. Follow these desktop best practices in QGIS:
- Set the export Coordinate Reference System (CRS) to WGS 84 (EPSG:4326) or Pseudo-Mercator (EPSG:3857).
- To create MBTiles in QGIS: run the Processing Toolbox tool "Generate XYZ tiles (MBTiles)". Set the minimum zoom (e.g., zoom 11 for landscape context) and maximum zoom (e.g., zoom 17 or 18 for outcrop-level resolution).
- To export a GeoTIFF: right-click the layer → Export → Save As. Under creation options, enable
COMPRESS=DEFLATEorJPEG. This shrinks file weight by up to 80% without noticeable visual fidelity loss.
Transferring files to your Android device
Transfer your .mbtiles or .tif file to your smartphone via one of these workflows:
- USB Cable: connect your phone to your workstation, enable "File Transfer / MTP" on Android, and copy the map file into your internal Downloads or Documents directory.
- Cloud Storage: upload to Google Drive on desktop and download the file onto device flash memory before leaving Wi-Fi coverage.
Importing the map into RockGeo Android
Launch RockGeo and open your active field survey project:
- Tap the Layers icon located on the map canvas.
- Select Add Base Map (or Import Raster/Vector Layer).
- Android's system file picker opens: browse to the folder where you stored your file and select it.
- RockGeo validates spatial metadata and creates the on-device index. The map renders immediately, calibrated to the true geographical coordinates of your target survey area.
Verifying in Airplane Mode before departure
Before mobilizing to the field camp:
- Enable Airplane Mode in Android settings to shut off all cellular and Wi-Fi data.
- Pan and zoom across the survey block in RockGeo. Your imported base map should render briskly across all cached zoom tiers.
- Enable device Location: your GPS cursor will plot accurately over the underlying satellite or topographic features.
Ready for remote geological exploration?
Download RockGeo for free on Android and maintain full control over your base maps and field data anywhere in the world.