By reading this article, users will learn about the different types of digital elevation models (DEMs) and digital terrain models (DTMs) that are available, the area covered by each dataset, which DEMs are available as open data, and which can be ordered commercially.
Digital elevation models (DEMs) are a type of three-dimensional mathematical model containing information about the elevation of the Earth’s surface.
It is important to distinguish between a digital surface model (DSM), which represents terrain together with man-made objects and elevated natural features, and a digital terrain model (DTM), which represents only the underlying bare-earth surface.
Figure 1. DSM and DTMIn geodesy, photogrammetry, and non-spatial disciplines, the terms DSM, DTM, DEM, DSM, and DTM are often confused.
For a simple understanding of how these terms are used in different fields, the distinctions can be summarized in the table below.
|
Term |
Photogrammetry |
Geodesy |
Geospatial / GIS |
|
DSM |
Often used to mean DSM (what is measured from a stereo pair), or a complex map combining 2D information with elevation. |
A broad concept covering terrain and surface features. Rarely used as a standalone term. |
Usually not used. |
|
DTM |
Not commonly used (photogrammetric workflows rarely remove forest manually). |
DTM / “bare earth” surface. A basis for engineering and design. |
DTM. Used for slope and drainage analysis. |
|
DEM |
A general term for an elevation raster. |
Used infrequently, mainly in scientific contexts. |
The most commonly used term. Often used broadly for elevation data stored in GeoTIFF format. |
|
DSM |
A primary product generated automatically from point clouds and rasterized with trees, buildings, and other above-ground objects. |
Rarely used in engineering surveys because above-ground objects can interfere with design work. |
Used for terrain shading, line-of-sight and radio visibility calculations, and 3D city modeling. |
|
DTM |
Requires complex filtering to remove forests and buildings — this is typically performed during post-processing, for example with LiDAR data, rather than directly in photogrammetry. |
A key concept. Formally established in professional standards. |
Used in bathymetry, geology, and soil science. |
In technical specifications, it is always necessary to clarify:
However, the ultimate objective of the entire DEM + DSM + DTM technological chain is to create a realistic 3D model for any location on Earth with the required parameters — a model that is visually indistinguishable from what the human eye perceives, while being enhanced by technical sensors to capture biological, chemical, physical, structural, natural and man-made, and phenomenological properties of our planet.
Data type: DSM
Satellite used for data acquisition: ASTER
Creation method: photogrammetric
Grid spacing: 30 m
Coverage area: from 83° north latitude to 83° south latitude
Acquisition period: 2000–2011.
2. ALOS World 30m DEM (AW3D30 V3)
Data type: DSM
Satellite used for data acquisition: ALOS
Creation method: photogrammetric
Grid spacing: 30 m
Coverage area: global
Acquisition period: 2006–2011.
3. MERIT DEM was created using SRTM and AW3D30 V1 data, with their errors reduced through additional processing.
Data type: DSM
Satellites / missions used for data acquisition: SRTM, ALOS
Creation method: photogrammetric
Grid spacing: 90 m
Coverage area: from 90° north latitude to 60° south latitude in the WGS84 coordinate system.
Acquisition period: 2000, 2006–2011.
4. TanDEM-X DEM – DEM data with a 30 m grid spacing can be downloaded from the portal.
Data type: DSM
Satellites used for data acquisition: TerraSAR-X and TanDEM-X
Creation method: radar interferometry
Grid spacing: 12 m, 30 m, 90 m (open-access version)
Acquisition period: 2010–2025.
5. SRTM
Data type: DSM
Spacecraft used for data acquisition: Space Shuttle Endeavour
Creation method: radar interferometry
Grid spacing: 30 m, 90 m
Coverage area: from 60° north latitude to 56° south latitude.
Acquisition date: 2000.
6. NASADEM
Data type: DSM
Spacecraft used for data acquisition: Space Shuttle Endeavour
Creation method: radar interferometry
Grid spacing: 30 m
Coverage area: from 60° north latitude to 56° south latitude.
Acquisition date: 2000.
Data type: DSM
Satellites used for data acquisition: TerraSAR-X and TanDEM-X
Creation method: radar interferometry
Grid spacing: 30 m (subject to certain restrictions), 90 m
Coverage area: from 50° north latitude to 50° south latitude.
Acquisition period: 2011–2026.
8. FABDEM
Data type: DTM
Satellites used for data acquisition: TerraSAR-X and TanDEM-X
Creation method: radar interferometry
Grid spacing: 30 m (global coverage except Azerbaijan and Armenia), 90 m
Coverage area: from 50° north latitude to 50° south latitude.
Acquisition period: 2011–2025.
In addition to global DEMs, local and regional elevation models are continuously being created and generally offer higher accuracy. Development follows two main paths: through commercial providers, or through websites that provide software for independent processing, including cloud-based processing. In the latter case, payment is usually required only for the primary source data, such as satellite imagery. Licensed provider companies either produce DEMs themselves or offer ready-made products. Let us consider some of them:
1. EU-DEM
Data type: DSM
Satellites / missions used for data acquisition: fusion of SRTM and ASTER data
Creation method: combined
Grid spacing: 30 m
Vertical RMSE: 7 m
Coverage area: Europe and Turkey
Acquisition period: 2000–2011.
2. EU-DTM
Data type: DTM
DEMs used: MERITDEM, AW3D30, GLO-30, EU DEM
Creation method: removal of above-ground objects from DEM data using machine learning
Grid spacing: 30 m
Coverage area: Europe and Turkey
Acquisition period: 2000–2021.
3. 3DEP (USGS 3D Elevation Program)
Data type: DTM
Creation method: LiDAR
Grid spacing: 2–5 m
Coverage area: United States (not the entire territory)
Acquisition period: 2012–2022.
4. ArcticDEM
Data type: DSM
Satellites used for data acquisition: WorldView-1, WorldView-2, WorldView-3, GeoEye-1
Grid spacing: 2 m
Coverage area: north of 60°N latitude
Acquisition period: 2016–2023. Updated every 3 years.
Data type: DSM
Satellites used for data acquisition: WorldView-1, WorldView-2, WorldView-3, GeoEye-1
Grid spacing: 8 m
Coverage area: south of 60°S latitude
Acquisition period: 2009–2017.
6. High Mountain Asia DEM
Data type: DSM
Creation method: photogrammetric
Grid spacing: 8 m
Coverage area: from the Tien Shan to the eastern Himalayas
Acquisition period: 2002–2016.
7. Vantor DTM/DSM/3D
Among the most up-to-date and high-accuracy products, available by subscription.
Vantor Geospatial Platform (MGP) Pro, formerly known as SecureWatch, is a subscription-based cloud platform providing on-demand access to global Earth information. In addition to imagery, it provides access to digital models and related products through Precision 3D / Vivid Terrain DEM data.
Precision3D Data Suite:
3D surface model, digital surface model (DSM) with 5 cm resolution,
digital terrain model (DTM) with 5 cm resolution, point cloud,
buildings. Grid products for regions at 30×30×50 cm / 50×50×100 cm.
DEM Post Distance (resolution):
Acquisition date: archive data + 2026.
8. RESTEC
RESTEC is a Japanese Earth observation technology center. The center receives and processes data acquired by both domestic satellites such as ALOS and foreign Earth observation satellites, as well as airborne and ground-based sensors, providing processed data to researchers and operational users, primarily under contracts with the Japan Aerospace Exploration Agency (JAXA), NTT DATA, and other organizations.
|
Product Type |
DSM/DTM |
|
Resolution |
2.5 m / 5 m |
|
Satellite |
JAXA-ALOS |
|
Coverage |
Global |
|
Horizontal accuracy |
5 m RMSE / 7 m CE90 May vary depending on terrain characteristics. |
|
Vertical accuracy |
5 m RMSE / 7 m LE90 May vary depending on terrain characteristics. |
|
Minimum order size |
400 km2 |
|
Delivery formats |
GeoTIFF; other formats available upon request. |
|
Delivery method |
Online or physical media (DVD) Panchromatic ortho (2.5 m resolution) |
|
Additional services* |
- Color ortho (2.5 m resolution) - File / Layer quality control *Format conversion service for 3D printers into STL format |
In the DEM field, the center offers four product options:
9. APOLLO MAPPING
A provider based in Chicago, Illinois, USA, specializing in streamlining the acquisition of geospatial products and providing guidance through the Image Hunter User Guide. It offers a search engine containing more than 200 million images and more than 60 datasets, including satellite imagery, aerial photography, and digital elevation models (DEMs), from companies such as VANTOR, Airbus Defence, Planet Labs, SpaceWill, including Jilin-1 (GF/KF/Optical/Video series, as well as nighttime and video products), SuperView Neo-3, ZiYuan-3 (mono and stereo), and others.
Elevation models are usually provided in two formats:
The table below presents the main characteristics of the elevation models offered by the company:
The company also provides high-quality solutions for building-related DSM applications.
Geometric building parameters such as height, volume, area, and facade inclination angle are calculated automatically.
10. SkyFi
SkyFi is a U.S. technology company that has created a platform for simplified access to satellite imagery, standardized derived products, including various DEM options, and AI-based analytics. In simple terms, it is a “marketplace” or “virtual constellation” that allows users to order satellite imagery almost as easily as ordering a pizza through an app.
It is a platform for ordering satellite imagery and geospatial analytics, also referred to as an Earth Intelligence Platform. It does not operate its own satellites, but aggregates data from more than 50 partners, including optical, SAR, and hyperspectral providers. SkyFi works with leading operators such as Vantor, Planet, ICEYE, and the Chinese company SIWEI.
Eleven products are presented, demonstrating nearly all currently available approaches to source digital modeling, from satellite imagery with spatial resolution of approximately 15–50 cm/pixel, through high-accuracy airborne and LiDAR-based processing with resolution down to 1–3 cm/pixel, as well as 360-degree video products:
11. Felt
Felt (Oakland, CA, USA) is a cloud-based GIS platform that allows users to create maps, applications, and dashboards within seconds. Whether working in urban planning, environmental science, real estate, or logistics, Felt provides organizations with advanced spatial capabilities.
In particular, this cloud platform enables step-by-step DEM creation.
The abbreviations DTM, DEM, and DSM refer to different types of elevation models, each representing a different version of the Earth’s surface. All three store elevation values digitally, typically as raster grids, but differ in the type of surface they represent.
Important note. Working with DEMs appears simple until processing begins at large scale. Elevation datasets are often very large raster files requiring significant amounts of memory, storage, and computing power. High-resolution terrain data can slow rendering and overload desktop computers, forcing teams to clip or downsample files in order to accelerate project workflows.
DEM-related workflows are summarized in the table below:
|
Parameter |
DEM |
DSM |
DTM |
|
Surface representation |
General elevation grid “Bare earth” or surface, depending on the dataset |
Represents the upper surface including above-ground features |
“Bare terrain” with surface features removed |
|
Vegetation and buildings |
Depends on the dataset |
Yes |
No |
|
Data structure and complexity |
Raster grid based on elevation values |
Raster generated from first-return LiDAR or photogrammetry |
Raster generated from a classified point cloud with ground points filtered and retained |
|
Typical data sources |
LiDAR, photogrammetry, satellite stereo |
LiDAR (first return), photogrammetry |
LiDAR (ground returns), photogrammetry with filtering |
|
Accuracy and suitability |
Depends on resolution and processing; suitable for general terrain analysis |
High level of detail for surface features such as trees and structures |
High accuracy for ground-based analysis such as slope assessment and hydrology |
|
GIS applications |
Regional elevation mapping, terrain visualization |
Urban modeling, line-of-sight analysis, solar studies, building height assessment |
Hydrology, flood modeling, drainage networks, slope and contour analysis |
|
Processing and maintenance |
Minimal processing when pre-processed data are used |
Moderate processing; updates may be required as urban conditions change |
Higher processing requirements due to ground classification and filtering |
Example of independent DEM creation through the Felt cloud platform:
Generalized capabilities for creating DTM/DSM products are summarized in the table below:
|
Characteristic |
Satellites |
UAVs (Drone) |
Terrestrial LiDAR |
|
Typical accuracy (vertical, Z) |
1–3 meters (RMSE) |
Centimeter-level
(0.05–0.15 m) |
Millimeter-level
(±0.01 m and better) |
|
Spatial resolution / point density |
Low / Medium |
Very high |
Maximum |
|
Ability to “see” the ground (DTM) |
Limited / Often impossible |
Good (for LiDAR) |
Outstanding |
|
Coverage area per acquisition |
Very large (thousands of km²) |
Local (0.5–10 km²) |
Site-specific (hundreds of m²) |
This article presents a selection of digital elevation models currently available. New DEMs are continuously being developed, while existing datasets are updated using new technologies, including AI-based methods for converting DSMs into DTMs. Today, geospatial products based on imagery and elevation models represent a major technological leap in terms of the balance between cost, time, and quality across key sectors of the economy and environmental sciences in the world’s leading countries. This is an established reality rather than an attempt by providers to promote a product without genuine demand. Naturally, not every company can afford to maintain an in-house team with sufficient geospatial expertise, especially given the limited number of qualified specialists in the industry.
For this reason, Geospatial Agency INNOTER LLC is ready to provide turnkey digital terrain model (DTM) production services, as well as select and supply ready-made commercial digital elevation models (DEMs) for any area worldwide.
