Digital elevation model (DEM)

Definition

A digital elevation model (DEM) is a 3D representation of a terrain's surface created from terrain elevation data. This model is primarily used in various applications, including geographic information systems (GIS), land-use planning, and environmental modeling, providing critical data on the Earth's surface. DEMs are often generated through satellite and airborne remote sensing techniques, enabling scientists and researchers to analyze topography and surface features with high precision.

5 Must Know Facts For Your Next Test

1. DEMs can be classified into two main types: raster DEMs, which use grid cells to represent elevation values, and vector DEMs, which utilize points and lines to define terrain features.
2. One of the primary sources for creating DEMs is remote sensing data collected by satellites such as the Shuttle Radar Topography Mission (SRTM), which has provided global coverage.
3. DEMs can support various applications, including hydrological modeling, urban planning, and disaster management by analyzing slope, aspect, and watershed boundaries.
4. The resolution of a DEM refers to the spacing of the elevation data points, with higher resolution models providing more detailed topographical information than lower resolution ones.
5. Using DEMs, researchers can visualize and analyze complex landscapes, allowing for better understanding and management of natural resources and environmental processes.

Review Questions

• How do digital elevation models (DEMs) contribute to understanding terrain features in remote sensing?
  • Digital elevation models (DEMs) are essential for analyzing terrain features as they provide detailed elevation data that helps visualize the Earth's surface. By using DEMs derived from remote sensing technologies like LiDAR or satellite imagery, researchers can create accurate 3D representations of landscapes. This information allows scientists to assess natural features such as mountains, valleys, and watersheds, facilitating studies related to hydrology, geology, and land-use planning.
• Discuss the importance of resolution in digital elevation models (DEMs) and its impact on remote sensing applications.
  • The resolution of digital elevation models (DEMs) plays a crucial role in determining the level of detail captured in terrain analysis. Higher resolution DEMs provide more precise information about topographic features, which is vital for applications such as urban planning and flood modeling. Conversely, lower resolution DEMs may overlook small-scale variations in the landscape that can significantly influence environmental processes. Thus, choosing the appropriate resolution based on the intended application is critical for obtaining accurate results.
• Evaluate the role of interpolation techniques in enhancing digital elevation models (DEMs) derived from remote sensing data.
  • Interpolation techniques are fundamental in refining digital elevation models (DEMs) by estimating missing or unknown elevation values based on available data points. These methods enable researchers to create seamless surfaces that accurately represent terrain characteristics. As remote sensing data may have gaps due to limitations in sensor coverage or atmospheric conditions, applying interpolation ensures a comprehensive understanding of the landscape. By improving the quality and completeness of DEMs, these techniques enhance their utility in various fields such as environmental modeling and resource management.

Related terms

LiDAR: Light Detection and Ranging (LiDAR) is a remote sensing technology that uses laser light to measure distances to the Earth, often producing highly detailed elevation data for DEMs.

Satellite Imagery: Images of Earth collected from satellites, which can be used in combination with DEMs to provide context and enhance the understanding of surface features.

Interpolation: The process of estimating unknown values between known data points, commonly used in creating DEMs by filling in gaps between measured elevations.