--- title: "Site twins: Digital twins and simulation | Nexus Observatory" description: "Site twins, inside Digital twins and simulation: city and site models, 3D Tiles and scene layers, BIM and asset information…" url: https://observatory.global/digital-twins/site-twins/ publisher: Nexus Observatory Inc. updated: 2026-10-29 --- [Nexus Observatory](https://observatory.global/) / [Digital twins and simulation](https://observatory.global/digital-twins/) / **Site twins** # The site in 3D, measured to scale. Site twins, inside Digital twins and simulation: city and site models, 3D Tiles and scene layers, BIM and asset information, photogrammetry and reality capture and more. Every item is traced to its specification, from OGC CityGML 3.0 Conceptual Model to OGC 3D Tiles 1.1 (Community Standard), and runs on the open Observatory Protocol. [Plan with us](https://observatory.global/contact/) Architecture [The protocol](https://observatory.global/protocol/specification/) **Technologies**: 9 **At the frontier**: 3 **Protocol functions**: 3 of 8 **Industries served**: 9 Reference design, drawn to scale · drag to turn · hover a part **01** What it is ## 3D, BIM and digital twins. The reference frames, formats, services, analysis methods, machine learning and 3D models that turn observations into located, queryable and decision-ready geographic information. Every platform, sensor, processing level and ground-segment step that turns remote measurements of the Earth into calibrated, analysis-ready evidence for a site, a region or a network. Each technology below carries what it is, what we do with it, and the standard it is drawn against. GIS, maps and GeoAI ### City and site models Semantic 3D models of buildings, terrain and infrastructure at defined levels of detail. We design and integrate. OGC CityGML 3.0 Conceptual Model GIS, maps and GeoAI ### 3D Tiles and scene layers Streaming of massive meshes, point clouds and models into web and desktop viewers. We design, integrate and operate. OGC 3D Tiles 1.1 (Community Standard) · OGC Indexed 3D Scene Layer (I3S) Community Standard GIS, maps and GeoAI ### BIM and asset information Building and infrastructure models and information management through design, build and operation. We design and integrate. ISO 16739-1 (IFC) · ISO 19650-1 (information management using BIM) GIS, maps and GeoAI ### Photogrammetry and reality capture Meshes, orthomosaics and point clouds reconstructed from drone and ground imagery. We design, integrate, deploy and operate. ASPRS Positional Accuracy Standards for Digital Geospatial Data (Edition 2) GIS, maps and GeoAI ### Indoor and underground models Indoor spaces and subsurface utilities for shelters, plant rooms and tunnels. We integrate. OGC IndoorGML · OGC Model for Underground Data Definition and Integration (MUDDI) GIS, maps and GeoAI ### Digital twin frameworks Linking a model to its physical counterpart with defined fidelity, update rate and purpose. We design, integrate and operate. ISO/IEC 30173:2023 · ISO 23247-1 (digital twin framework for manufacturing) **Frontier** · GIS, maps and GeoAI ### Sensor-fused live twins Twins updated continuously from sensors, cameras and EO, with provenance on every change. We design, integrate and operate. OGC SensorThings API 1.1 · OGC API - Connected Systems **Frontier** · GIS, maps and GeoAI ### Geospatial augmented reality Overlaying the twin on the real site for crews through located and oriented devices. We design and integrate. OGC GeoPose 1.0 **Frontier** · Remote sensing and Earth observation ### Onboard AI and in-orbit processing Detecting events and compressing to products in orbit so only what matters is downlinked. We integrate. CEOS ARD (as output target) **02** Architecture ## Where it sits, and what it speaks. Site twins draws on 3 domains and 24 layers of the spectrum; the highlighted layers carry this area. It speaks 3 of the protocol's 8 core functions. Reference systems and geodesy 7 Vector, raster and array formats 10 Tiling, maps and visual services 7 APIs, catalogues and discrete global grids 8 Spatial analysis and siting 10 GeoAI 10 3D, BIM and digital twins 8 Metadata, quality and publication 5 Platforms and orbits 8 Optical, spectral and thermal sensors 8 Radar, lidar and microwave sensors 10 Processing levels and analysis-ready data 9 Calibration and validation 8 Tasking, ground segment and access 9 Data cubes, analysis and archives 7 Frontier and research 8 01**Join** Identity, attestation quote, signed policy. 02**Admit** Admitted for a stated scope, nothing wider. 03**Describe** What, where, how and by whom, with calibration. 04**Time** One clock across the grid, with its error bound. 05**Observe** Every value with quality and provenance. 06**Qualify** Tested against the specification, state on record. 07**Federate** Signed exchange across grids and trust domains. 08**Orchestrate** Software and configuration by signed plan. **03** On the grid ## The ground, measured before it is modelled. Real elevation, line of sight, an orbit swath and a GeoAI pass, each an interactive explainer on open terrain data with its source shown. [Line of sightA 30 m mast against the terrain.](https://observatory.global/earth/#viewshed) [ReliefTerrarium-encoded DEM, contours by marching squares.](https://observatory.global/earth/#elevation) [Hillshade and slopeOne gradient, a sun you can move.](https://observatory.global/earth/#hillshade) [Geodesic gridStations counted into 10,242 cells.](https://observatory.global/earth/#grid) **04** In the field ## Where this runs, sector by sector. 3 deployment scenarios from the sector research that rely on site twins. [Development and humanitarian Displacement-site connectivity and sensingPoint-to-multipoint wireless, satellite backhaul, solar and water-point sensors with protection safeguards.](https://observatory.global/sectors/humanitarian/) [Environment and climate Methane fenceline and site-level continuous monitoringRegulatory cadences in the EU and reporting levels in voluntary frameworks.](https://observatory.global/sectors/environment/) [Agriculture Farm or cooperative agromet network with crop modelsCompact stations and soil probes feeding irrigation, disease and frost models.](https://observatory.global/sectors/agriculture/) **05** Open and enterprise ## Open by default. Enterprise by contract. The open counterpart lives on the main site for anyone to read and run. The enterprise service is designed, deployed and operated with you, under contract. Open, on the main site - Simulation methods with worked examples - Open terrain and grid layers Enterprise, on this site - Drone survey and 3D site twins - Network planning studies - Scenario studies **06** The rest of the line ## Digital twins and simulation, area by area. [Digital twins and simulation Network twinsCoverage, capacity, power and timing, simulated.](https://observatory.global/digital-twins/network-twins/) [Digital twins and simulation Earth twinsTerrain, hydrology and atmosphere, on live observations.](https://observatory.global/digital-twins/earth-twins/) [Digital twins and simulation Scenario simulationFloods, heat, load and failure, run before they happen.](https://observatory.global/digital-twins/scenario-simulation/) [Digital twins and simulation PlanningFrom the twin to a plan you can tender.](https://observatory.global/digital-twins/planning/) ## Bring us the site. Survey, design, deployment and operation for site twins. The form names who receives your details. [Talk to us](https://observatory.global/contact/) [contact@observatory.global](mailto:contact@observatory.global?subject=Digital%20twins%20and%20simulation%3A%20Site%20twins) [Nexus Observatory](https://observatory.global/)**Digital twins and simulation** . Model the site before you build it.[Talk to us](https://observatory.global/contact/) Digital twins and simulation - [Site twins](https://observatory.global/digital-twins/site-twins/) - [Network twins](https://observatory.global/digital-twins/network-twins/) - [Earth twins](https://observatory.global/digital-twins/earth-twins/) - [Scenario simulation](https://observatory.global/digital-twins/scenario-simulation/) - [Planning](https://observatory.global/digital-twins/planning/) Technologies - [Reference systems and geodesy](https://observatory.global/technologies/gis/reference-systems-and-geodesy/) - [Vector, raster and array formats](https://observatory.global/technologies/gis/vector-raster-and-array-formats/) - [Platforms and orbits](https://observatory.global/technologies/eo/platforms-and-orbits/) - [Optical, spectral and thermal sensors](https://observatory.global/technologies/eo/optical-spectral-and-thermal-sensors/) - [Edge inference, model serving and optimisation](https://observatory.global/technologies/ai/edge-inference-model-serving-and-optimisation/) - [Foundation models for Earth observation and geospatial](https://observatory.global/technologies/ai/foundation-models-for-earth-observation-and-geospatial/) Industries - [Cities](https://observatory.global/industries/cities/) - [Water](https://observatory.global/industries/water/) - [Nature](https://observatory.global/industries/nature/) - [Agriculture](https://observatory.global/industries/agriculture/) - [Energy](https://observatory.global/industries/energy/) - [Infrastructure](https://observatory.global/industries/infrastructure/) - [Mining](https://observatory.global/industries/mining/) Service platforms - [Observatory Protocol](https://observatory.global/protocol/) - [Protocol & Grid](https://observatory.global/grid-services/) - [Software](https://observatory.global/software/) - [Hardware & power](https://observatory.global/hardware/) - [Sensors & instruments](https://observatory.global/sensors/) - [Connectivity](https://observatory.global/connectivity/) - [Edge compute & AI](https://observatory.global/edge-ai/) © 2026 Nexus Observatory Inc. [Privacy](https://observatory.global/legal/privacy/) [Terms](https://observatory.global/legal/terms/) [Accessibility](https://observatory.global/legal/accessibility/) [Cookie settings](https://observatory.global/privacy-choices/) [Data credits](https://observatory.global/credits/)