Deploying Maps and Digital Twins Without Internet Access
An offline deployment needs an application that starts locally, usable and permitted local map and 3D data, and authentication and other dependencies that no longer call external services. Caching a homepage covers only part of the visited content. Validate the deployment against the required geographic area, zoom levels and business operations.
On this page5 sections
Define which network connection is unavailable
Users without internet access, servers without outbound access and terminals disconnected from the local network are different conditions. The first two may still use internal map, identity and data services. The third needs a separate plan for local application resources and business data. Diagram access between terminals, application servers, map services, identity systems and update media before agreeing to “offline.”
List the required operations: viewing a specific site, switching floors, querying equipment, searching addresses or navigating between cities. These need different resources. If the application manages one factory, first decide whether the factory plan and models are sufficient; nationwide map coverage should not be assumed.
Inventory resources beyond the page itself
The official CesiumJS offline guide identifies external imagery, base-layer selection and geocoding as configuration concerns, and recommends a local server for static 3D resources. Copying the engine files to a server establishes only part of the local deployment, not the availability of every function.
| Resource or service | Confirm before deployment | Verify offline |
|---|---|---|
| Imagery, terrain and map tiles | Area, levels, coordinates and permitted source | No gaps or misalignment at boundaries and close range |
| Models, textures and decoders | Main files and referenced dependencies are complete | Previously unvisited areas load on first access |
| Scripts, fonts, styles and icons | No external CDN dependency in the build | Text and interaction work with an empty cache |
| Identity, search and business APIs | Internal endpoints and unavailable functions are identified | New sign-in, queries and failure messages work |
Record the version, provider, file location or endpoint and update owner for each entry. The asset and protocol compatibility matrix (in Chinese) can hold evidence for existing resources. A generic claim of “offline map support” cannot replace that inventory.
Check software rights and map data rights separately
Permission to use an open-source engine does not imply permission to download and redistribute every imagery, terrain or building source it connects to. Cesium ion's archive and export documentation restricts these features to data you uploaded. Asset Depot resources such as Cesium World Terrain and Cesium OSM Buildings are excluded from that download route. Attribution requirements also remain relevant.
The OpenStreetMap standard raster tile service policy prohibits bulk downloading from tile.openstreetmap.org for offline use. Public viewing access is not permission to collect an entire map. Choose a provider with explicit offline terms, a self-hosted service or resources the customer is entitled to provide. Check the agreed area, term, attribution and update method.
Also verify activation, renewal and offline licensing for commercial components. If a self-hosted service is required, include its license files and maintenance responsibilities in delivery. Open source, private deployment and operation without internet access are separate conditions.
Deliver a reinstallable package, not just a demonstration computer
Include the application version, resource inventory, checksums, map service configuration, internal domain and certificate requirements, installation instructions and update procedure. Decide whether container images, dependency packages and conversion tools must enter the isolated network. A successful installation that downloaded dependencies online does not prove later installation will work offline.
Application packages, data packages and environment configuration may be managed separately, but record their compatible combinations. Import new map areas, replacement models or fonts through the approved process. Verify versions and completeness before checking business points. Retain the previous working combination and rollback steps so that a model update cannot silently omit textures or object mappings.
Accept the full scope with a cold start
Under the agreed isolation conditions, start with a new browser profile or an empty test cache. Sign in, enter unvisited areas, reach the maximum agreed zoom level, switch base layers and floors, query equipment and restart services. Record external-domain requests and distinguish necessary business dependencies from removable calls. A clean homepage screenshot is insufficient.
Test areas outside the supplied coverage and unavailable search functions as well. They should show a clear limitation rather than wait indefinitely. Finally, reinstall on another environment that meets the agreed specification and repeat the operations. Record the network boundary, resource versions, tested areas and levels, and functions that still require internal services.