Guide – Exploring the Past with LIDAR

Imagine being able to see the landscape around you in a completely new way—an invisible layer revealing the hidden structures of the past, right beneath the surface. This is the power of LIDAR (Light Detection and Ranging), a technology that has revolutionized archaeology and landscape studies. In this article, we’ll take a look at how LIDAR works, where to find LIDAR data, and how to interpret it to uncover the secrets of your local landscape.

What is LIDAR?

LIDAR is a remote sensing method that uses laser light to measure distances between a sensor and the Earth’s surface. The LIDAR sensor sends out rapid pulses of laser light, and by measuring the time it takes for these pulses to bounce back, the system can create incredibly accurate three-dimensional maps of the terrain.

This technology is particularly useful in archaeology because it allows researchers to “see through” dense vegetation and other obstructions. By scanning large areas from the air (usually via a plane or drone), LIDAR can reveal ancient structures, pathways, and other features hidden beneath the canopy or soil—features that would be nearly impossible to detect with traditional methods.

How Does LIDAR Work?

The basic process of LIDAR involves the following steps:

Emission of Laser Pulses: A laser is emitted from an aircraft or drone, directed towards the ground below.

Data Collection: The laser pulses bounce off the surface and return to the sensor. By measuring the time it takes for each pulse to return, LIDAR systems can calculate the distance between the sensor and the surface below.

Data Processing: The return time for each pulse is converted into highly detailed 3D point clouds, which represent the topography of the area. These point clouds can then be used to generate highly accurate digital elevation models (DEMs) or surface models.

Analysis and Visualization: These models can be further processed to reveal features like ancient structures, roads, and earthworks, offering archaeologists and researchers a clearer picture of past human activity.

Where Can You Access LIDAR Maps?

LIDAR data is often collected by government agencies, research institutions, and private companies. Thankfully, several free LIDAR mapping services allow public access to this valuable data. Below are a couple of resources where you can explore LIDAR data for your own area:

UK LIDAR Data Service (UK LIDAR Data): Managed by the UK Environment Agency, this service provides free access to high-resolution LIDAR data for England, Wales, and Northern Ireland. It allows users to view and download data in various formats, which can be helpful for understanding the terrain and identifying archaeological sites.

OpenTopography (OpenTopography): OpenTopography is an international platform that offers free access to LIDAR datasets from across the globe, including many archaeological regions. The site provides downloadable data for creating DEMs and other visual models, enabling users to view topography in more detail.

Differences Between the Services

Both of these LIDAR mapping services offer free access to LIDAR data, but there are a few differences to consider:

Coverage Area: The UK LIDAR Data Service focuses specifically on the UK, while OpenTopography offers datasets from various countries around the world. If you’re interested in a global scope or specific international sites, OpenTopography might be your best choice.

Data Access and Usability: UK LIDAR allows for direct access to high-resolution data files that can be easily imported into GIS software, while OpenTopography offers a user-friendly interface for visualizing the data before downloading. If you’re new to LIDAR mapping, OpenTopography’s interactive map can be a great way to explore the data visually before downloading raw datasets.

How to View Your Own Area on LIDAR

Now that you have access to LIDAR data, you can start exploring your local area. To get started:

Visit the LIDAR Service Website: Go to either the UK LIDAR Data Service or OpenTopography, depending on your region.

Search for Your Location: Enter the location you’re interested in (e.g., your town, village, or any region of archaeological interest) into the search bar or use the map interface to navigate to your area.

Select Data Layers: Many platforms will allow you to overlay different layers, such as terrain models or vegetation indices. You can often choose between raw elevation data or more processed versions, such as shaded relief maps, which can help bring the features of the landscape to life.

Explore the Data: Once you’ve located your area, zoom in and start examining the terrain. You might begin to notice subtle features—like circular depressions, straight lines, or embankments—that could be clues to ancient settlements, roadways, or other archaeological features. These features are often hidden to the naked eye but come to life in the LIDAR data.

How to Interpret What You’re Seeing

Interpreting LIDAR data requires a bit of practice, but here are some general tips for reading the maps:

Elevation Models: Digital Elevation Models (DEMs) can show the height of the terrain. Areas that are more elevated, such as hills or mounds, may indicate the presence of ancient structures, burial mounds, or defensive earthworks.

Point Clouds: The point cloud representation shows the distribution of laser points on the surface. Look for patterns in the density and clustering of points, which may hint at man-made features. For example, straight lines may indicate roads, walls, or boundary markers.

Shaded Relief Maps: These maps provide a more visually accessible way to view the landscape’s features. Shadows are used to accentuate changes in elevation, making it easier to spot features such as ditches, mounds, or roads that may have been built by past societies.

Encouraging Your Own Adventure

By using LIDAR, you’re not just looking at a map—you’re uncovering a hidden world that’s waiting to be discovered. It’s like stepping into the shoes of an archaeologist or explorer, finding clues to our shared history right in your own backyard. Even if the terrain seems unremarkable at first glance, LIDAR can reveal the subtle traces of human activity that lie just beneath the surface.

So, grab your binoculars, explore the hidden topography of your area, and let the journey of discovery begin. Who knows what ancient roads, forgotten ruins, or hidden villages might be waiting to be uncovered?

Professional LIDAR Services: Unlocking Precise 3D Mapping

While free LIDAR mapping services provide a fantastic entry point for exploring the landscape, professional LIDAR services offer higher-resolution data, more advanced processing capabilities, and tailored solutions for complex archaeological or geographical projects. These services are often used by research institutions, governments, engineering firms, and private companies to gather highly accurate data over large areas. Professional LIDAR services also allow for more precise interpretation of the data, particularly in environments that require specialized expertise.

How Professional LIDAR Services Work

Professional LIDAR services typically involve the following process:

Data Collection: Professional LIDAR data is typically collected by aircraft or drones equipped with LIDAR sensors. These sensors emit laser pulses and record the time it takes for them to return, measuring the distance to the ground below. Data is collected for both the surface and vegetation layers, allowing for detailed topographic mapping.

Point Cloud Processing: After data collection, the LIDAR point clouds (3D data points) are processed and cleaned to create digital elevation models (DEMs), which can then be used to generate 3D models of the terrain. These models can include both visible and subsurface features, depending on the capabilities of the LIDAR system used.

Customized Data Output: Professional services often offer more advanced post-processing and analysis options, including tailored visualizations, contour maps, and 3D terrain models, specifically designed for archaeological, environmental, or engineering needs.

Project-Specific Analysis: With professional LIDAR services, you can get more accurate and detailed analysis, such as feature identification, vegetation analysis, or flood risk assessment. In archaeology, this can mean uncovering subtle earthworks, hidden structures, or ancient pathways that would be otherwise invisible to the naked eye.

Popular Professional LIDAR Services

Here’s a list of resources and services that provide professional LIDAR data and technology. These services are often tailored to specific industries, and they typically require purchasing or contracting services for data collection and analysis:

Riegl LIDAR (Riegl LIDAR): Riegl is a leader in the field of professional LIDAR systems and sensors. They offer a wide range of LIDAR solutions for terrestrial, airborne, and mobile mapping applications. Their systems are used in topographic surveys, archaeology, forestry, and environmental studies.

Leica Geosystems (Leica Geosystems): Leica offers a broad range of professional LIDAR systems and services. They specialize in high-precision, 3D data collection for industries such as construction, mining, and archaeology. Leica provides both hardware for LIDAR collection and software tools for data processing and analysis.

Optech (Teledyne) (Optech): Optech, now part of Teledyne, provides advanced LIDAR systems for airborne and terrestrial mapping. Their products are used for applications ranging from archaeology and forestry to floodplain mapping and environmental monitoring.

Topcon Positioning Systems (Topcon Positioning Systems): Topcon offers LIDAR systems that are suitable for a wide range of mapping projects, including those in the civil engineering and infrastructure sectors. Their solutions include airborne, mobile, and ground-based LIDAR systems.

Surdex Corporation (Surdex): Surdex provides professional LIDAR mapping services, offering high-resolution data collection for industries such as mining, forestry, and land development. They provide both LIDAR data collection and processing services tailored to their clients’ needs.

Quantum Spatial (Quantum Spatial): A provider of geospatial solutions, Quantum Spatial specializes in high-accuracy LIDAR data collection and analysis for government agencies, environmental monitoring, and infrastructure planning. They are known for their expertise in applying LIDAR technology to large-scale mapping projects.

Aerometric (Aerometric): Aerometric provides airborne LIDAR data collection services for the environmental and natural resource sectors. They specialize in topographic and bathymetric LIDAR services, offering detailed mapping solutions.

3D Laser Mapping (3D Laser Mapping): 3D Laser Mapping offers both hardware and software solutions for LIDAR applications. They specialize in providing highly accurate data for mining, construction, archaeology, and urban planning projects.

Further Information and Resources

LIDAR 101: Introduction and Applications – An introductory guide on how LIDAR works, its applications, and industries that use it. Read here

LiDAR Technology Overview from NASA – A detailed explanation of LIDAR technology, how it’s used in Earth sciences, and its contributions to environmental monitoring. Explore here

The LIDAR Magazine – A publication dedicated to LIDAR news, technologies, and trends in the geospatial industry. Visit here

LIDAR News – Another valuable resource for LIDAR news, case studies, and technology developments. Visit here

LIDAR is a powerful tool, and with these resources, you can explore how professional services can be used to create high-precision maps and models for your specific needs. Whether you’re involved in archaeology, environmental studies, or simply interested in understanding the landscape in new ways, these professional LIDAR services can unlock a wealth of information hidden beneath the surface.