With Plex-Earth, you gain access to top-notch elevation data from the most high-quality up-to-date terrain providers and create terrain models for your project. This information can be used for preliminary design and it is also perfect for getting the general morphology of a project site and making quick estimations of the earthworks.
Plex-Earth 2023 offers terrain information from the following providers:
Explanation on Vertical Datum Surface
Google Elevations
Google Elevations is one of the world's most well-known and most comprehensive 3D maps over the internet to represent the Earth as a three-dimensional globe.
| Coverage | Global |
| Vertical Datum Surface | Geoid (EGM) |
| Resolution |
Varies between 1 m (3 ft) and 30 m (100 ft) More information can be found here. |
Cesium
Cesium is the open platform for software applications designed to unleash the power of 3D data.
| Coverage | Global |
| Vertical Datum Surface | Ellipsoid (WGS84) |
| Resolution |
Varies between 1 m (3 ft) and 30 m (100 ft) More information can be found here. |
Terrain Tiles on AWS
Terrain Tiles on AWS is a global dataset providing bare-earth terrain heights, tiled for easy usage and provided on S3.
| Coverage | Global |
| Vertical Datum Surface | Geoid (EGM) |
| Resolution |
Varies between 1 m (3 ft) and 30 m (100 ft) More information can be found here. |
We generally suggest the above terrain data be used for cases in which is mainly required the morphology of the area rather than the absolute accuracy, such as in preliminary design. For cases that fall under strict accuracy requirements, we recommend that our users order drone measurements, through our global network. More information about the DroneFlights service can be found here.
Explanation on Vertical Datum Surface
Each terrain provider uses a different vertical datum as the basis for their elevation data. Vertical datums serve as reference points from which elevation (positive altitudes and negative depressions) can be determined.
Google Earth and Terrain Tiles on AWS use a geoid model as a vertical datum while Cesium uses an ellipsoidal model.
To differentiate between geoid and ellipsoid models, see the figure below.
Photo: Esri (link), All Rights Reserved
The geoid approximates the mean sea level (MSL). The MSL surface is in a state of gravitational equilibrium. The shape of the ellipsoid was calculated based on the hypothetical equipotential gravitational surface. Scientists have developed several ellipsoidal models of the Earth over the years. The most well-known of these serve as the basis for the WGS84 coordinate reference system. Unlike ellipsoidal models, geoid models are locally based—or, at least, more local than the entire surface of the Earth.
To further explain, altitude values from different datums for the same point can have a significant difference depending on one's workflow as Google Earth and AWS use orthometric heights while Cesium uses ellipsoidal heights.
The figure below shows the relationship between the different heights - geoid, ellipsoidal, and orthometric.
Photo: A. Al-Zoubi, et al. (2007), link, All Rights Reserved
Ellipsoid height (h) is the difference between the ellipsoid and a point on the Earth’s surface. If you have coordinates that were captured with a GPS receiver, the elevation data reference the ellipsoid, meaning it has to be transformed to match the more accurate geoid instead.
Geoid height (N) is the offset value between the reference geoid and the ellipsoid models.
Orthometric height (H) is the distance between a point on the Earth’s surface and the geoid.
We hope that you have found this article about our terrain providers, helpful. Feel free to contact us at support@plexscape.com for any questions you may still have.
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Compatibility includes:
AutoCAD Version: 2024 , 2023 , 2022 , 2021 , 2020 , 2019 , 2018 , 2017 , 2016
Civil 3D® Version: 2024 , 2023 , 2022 , 2021 , 2020 , 2019 , 2018 , 2017 , 2016
AutoCAD Architecture Version: 2024 , 2023 , 2022 , 2021 , 2020 , 2019 , 2018 , 2017 , 2016
BricsCAD Pro: V23 , V22 , V21