Satellite Ground ContextView buildings, vegetation, roads, shorelines, and access conditions where the selected imagery provides sufficient detail.
BLUEMARK MCS GIS SOLUTIONS
Offline Maps
Offline Satellite Imagery for GIS Field Operations
OfflineMap provides prepared satellite and map packages for field teams who need geographic context when mobile data coverage is weak or unavailable. Use imagery to orient survey crews, inspect distribution corridors, identify access routes, and review field locations alongside separate GIS asset layers such as poles, feeders, transformers, and substations. Map packages are prepared for a defined coverage area and selected zoom levels to balance image detail, storage size, and device performance.
Key Benefits
Designed to make offline imagery practical for distribution utility surveys and other GIS field activities.
Works Without Mobile DataKeep the prepared map area available on the device after the package has been downloaded and imported.
GIS Overlay ReadyUse imagery as a basemap beneath separately maintained poles, lines, meters, transformers, and other GIS layers.
Survey-Area PackagesCustomized maps by service area, municipality, feeder corridor, or project boundary to avoid storing unnecessary coverage.
Adjustable Map DetailChoose zoom levels and imagery resolution to balance legibility, download size, and device storage.
Responsible Imagery UsePackages use imagery whose license permits the intended offline storage, use, and distribution.
Recommended Map Formats and Resolution
For Android field use, the recommended delivery format is raster MBTiles, provided the target map application supports it. Keep the original source imagery separately for processing and future updates.
| Format | Best use | Resolution / detail guidance |
|---|---|---|
| MBTiles (.mbtiles) | Offline tiled basemap in compatible Android GIS or map apps. | Client to specify the zoom range needed. A practical starting range is zoom 10–18; zoom 19 may be included only where source imagery supports that detail and the storage is adequate. |
| GeoTIFF (.tif / .tiff) | Source imagery, clipping, reprojection, mosaicking, and QGIS processing. | Preserve the source pixel size. Satellite source options may range from about 10 m/pixel for Sentinel-2 to about 0.3–0.5 m/pixel for licensed commercial imagery. |
| XYZ tile folder (.zip) | Portable tile sets when the target app accepts a local XYZ directory or ZIP import. | Use the same zoom range as the corresponding MBTiles package. Confirm whether the app expects XYZ or TMS tile row numbering. |
| GeoPackage (.gpkg) | GIS data exchange or raster/vector storage in software that supports the relevant GeoPackage content. | Resolution depends on the raster source. Confirm compatibility with the intended Android app before publishing. |
Resolution is not the same as zoom level. Ground sample distance (for example, 10 m/pixel or 0.3 m/pixel) describes the source imagery's pixel size on the ground. Web-map zoom levels determine how many tiles are generated and how far the user can zoom in. Higher zoom levels do not create new detail if the source imagery is lower resolution.
Available Map Packages
Published files in the OfflineMap download folder are listed below. Each package are be named with its coverage area, imagery source, and zoom range where practical.
No map packages have been published yet.
Listed file extensions are .mbtiles, .zip, .gpkg, .tif, and .tiff.
Listed file extensions are .mbtiles, .zip, .gpkg, .tif, and .tiff.