Topographic surveying is a detailed step-by-step mapping process used to capture the natural and man-made features of a landscape. It provides critical elevation and contour data for construction, engineering, and land development.
The following article will walk readers through that process, detailing how 3D laser scanning technology is transforming topographic surveying from the ground up. And how 3D laser scanning and 3D surveying technology at large can bring unprecedented speed and accuracy to a centuries-old profession.
Topographic Mapping: A Brief History
Historically, generating a topographic map was a grueling process. Research tells us that Geospatial mapping traces its beginnings to ancient Egypt, circa 3,000 BC.
That’s when the first pyramids were constructed at Giza – a time when early land surveying techniques detailed boundary changes from annual Nile River flooding. By 300 AD, geospatial data collection had become an established profession, and by medieval and early Renaissance Europe, survey maps and surveying equipment were helping kings and empires visualize – and conquer – their world, both at home and abroad. In the United States, the first USGS (United States Geological Survey) topographic map was completed in 1892.
The Art and Science of a Topographic Survey
The first step in the topographic mapping process begins with identifying what is meant by “natural and man-made features of a landscape.” Specifically, that means the artificial and physical features of the terrain– mountains, hills, valleys, rivers, buildings, telephone poles, fences, etc.
Structured, categorized and territorialized, how we view, use and share the land we occupy must be organized in such a way that land surveying data can be universally understood and acted upon. Thus, today’s cities and suburbs, the protection and health of natural lands (like forests), safe roads and bridges, even the study of other worlds – none of it would be possible without topographic maps and what’s become known as the topographic survey process, increasingly enabled by 3D surveying technology.
Technology and the Future of Topographic Mapping
Topographic mapping is the backbone through which our modern society exists. And increasingly, that backbone rests on advanced geospatial technology to generate digital terrain models.
What is the Topographic Survey Process?
The topographic survey process includes the steps necessary to generate a topographic map. The process begins with preplanning research. Reviewing older maps and landform data is essential. This preliminary data will eventually be compared to the new maps generated by a variety of possible tools.
Post Survey Results
Once this data is collected, a discussion will be had regarding the level of detail the new map/s will require. This will help determine the amount of time and expense it will take to complete the topographic survey, which could be measured in days, weeks, or months. There is no set-in-stone timeline.
Next, the area in question is mapped, the data is processed, checked for quality assurance and imported to surveying software. Only then will the information be shared with the client, whether it’s an engineering firm, city agency, or another private entity.
Surveying Equipment: Tools of the Trade
There are many “tools” surveyors can use to create a topographic map including total stations, theodolites, and LiDAR enabled scanners.
LIDAR-based terrestrial laser scanners are another modern approach surveyors opt for, along with satellites, photogrammetry, and infrared equipment. Often these tools are used in combination with one another to ensure data redundancy and the most accurate results.
LIDAR (Light Detection and Ranging)
Uses laser-based detection instruments that generate a point cloud consisting of millions of points of data. The devices measure the time it takes for the laser beam to be reflected to the scanner, producing a highly accurate 3D image.
Photogrammetry Tools
Measurement and mapping from high-resolution digital cameras, often from aerial vantage points.Aerial UAV
Aerial UAVs can use high-altitude photogrammetry or LIDAR-based imaging to generate 2D and 3D maps of a given area.
GNSS
Signals sent to a global positioning receiver and a satellite uses trilateration to determine a precise location on Earth, including elevation. Useful for large-area mapping.Total Station
Combines an electronic theodolite and an electronic distance meter (EDM) to provide accurate measurements of horizontal and vertical angles as well as distances.FARO Geospatial Solutions
As a leader in reality-capture technology, FARO offers a variety of hardware and cloud-based solutions that enable or assist in topographic mapping.FARO Focus Laser Scanner for Digital Surface Modeling
Featuring high accuracy levels, the Focus scanner is best suited for as-built capture and modeling as well as as-built quality control and infrastructure assessment. This includes 3D laser scanning for buildings, roads, bridges, tunnels, and more. With its embedded GNSS, the Focus can merge BIM with GIS, making it an even more formidable geospatial tool while it’s laser-based point cloud generation can effectively capture elevation changes, slopes, and surface contours – all critical elements of a topographic map.
FARO Orbis Premium for Mobile Surveying Equipment
The Orbis Premium Mobile Scanner features SLAM technology, an acronym which stands for simultaneous localization and mapping. This means it can identify its position relative to the point cloud it's creating – not dissimilar to how products like iRobot’s autonomous vacuum cleaner, Roomba, uses infrared to scan its environment and determine its exact location within that 3D space. Orbis is particularly useful for infrastructure surveying tasks providing engineers, surveyors, and urban planners with rich visual data to improve project insights and decision-making.
Flash Technology: When Speed and Accuracy Matter Most
Both Orbis and Focus benefit from FARO’s proprietary Flash Technology. Flash Technology for Focus combines the accuracy of a 3D scan with the speed of a panoramic camera. This is ideal in topographic surveying situations where roads and rail might require temporary closures to obtain the scans required. For Orbis, Flash is built into the SLAM algorithm and allows for stationary scans in approximately 15 seconds with excellent detail from a true mobile mapping solution.
Sphere XG for Data Upload and Global Collaboration
Sphere XG is where on-site data is analyzed, processed, and shared. As FARO’s cloud-based platform, users can upload their survey data, collaborate remotely with project stakeholders anywhere in the world, and be confident in a data-secure solution that helps surveyors organize the 3D scans they take.
FARO® As-Built™ for AutoCAD: LiDAR, 3D Laser Scans, and Survey Data Integration
With the ability to convert raw point cloud data into precise, scalable models, As-Built for AutoCAD provides real-world data for planning and analysis. By integrating LiDAR, 3D laser scans, and survey data, the software enhances accuracy in mapping and analysis and is useful in land surveying, urban planning, and infrastructure development.
Types of Topographic Surveys
There are many types of topographic surveys. Sometimes multiple surveys are required for the same area. The following is a list of some of the most common. And in the context of the topographic survey process, will determine what type/s of surveys will need to be performed.
Location Survey:
Are used primarily when updating older construction projects. They are often required for zoning permits.
Engineering Survey:
Provides topographic data for designing and constructing roads, bridges, buildings, and utilities and are often highly detailed, project site focused.Remote Sensing Survey:
Gathers data about the Earth's surface using satellite or aerial sensors. Like geodetic surveys, these cover large areas and can provide topographic information for difficult-to-reach locations.
Mine and Quarry Survey:
These are topographic maps of open-pit or underground mines and are critical for resource extraction planning, as well as safety, and environmental management.Volumetric Survey:
Measures the amount of soil, gravel, and rock, in a given area, often for construction, mining, or land reclamation purposes. These surveys are used to calculate volumes for earthworks or resource extraction.
Environmental Survey:
These surveys map natural features for environmental monitoring and planning. They include: flood mapping, vegetation cover, and erosion studies.Land Surveying Techniques Delivered
As evidenced from above, the topographic survey process is an involved, highly detailed assessment. It is the pre-planning review of all the land surveying geospatial solutions needed to get the job done right with the greatest speed, accuracy and precision (and most affordable). It’s also about identifying the type of topographic survey (or surveys) required.
Organizing this level of detail and coordinating so many project stakeholders is never easy. Project management can be difficult. Budgets can be strained. Nerves can fray.
But today’s modern terrestrial laser scanners and mobile LIDAR technologies are the tools the geospatial mapping community has to help mitigate some of these challenges.
Eager to learn more about FARO’s geospatial technology solutions and discover which products work best for you and your company’s needs?