Geospatial Data: Your In-Depth Guide
We often talk in detail about the measurement capabilities of survey equipment. However, what’s equally important is the ability of products to record, catalogue, and sort geospatial data.
Geospatial data helps describe objects, boundaries, events, and other features within a particular location. Being able to accurately interpret this information is essential for on-site activities in various industries, including construction, rail infrastructure, survey, and utilities.
In this piece, we take a deep dive into the various kinds of geospatial data that leading survey equipment will produce. Having a greater understanding of geospatial data analysis will help optimise your time spent both on and off-site.
Explaining the 3 main types of geospatial data
Essentially, geospatial data can be any information that helps you identify a specific location on the Earth’s surface. Each type will typically describe an aspect of that area, such as the distance between two points, elevations, corner angles, and attributes, as well as the lifespan of materials and features within the environment. Large sets of geospatial data from various sources are required to create a complete reconstruction of a location, which is why equipment that can perform rapid and accurate measurements is highly demanded.
1.Vectors and Attributes
Vectors are the most familiar type of geospatial data, consisting of points, lines, and polygons that add detail to maps. This data provides insight into the nature of a location in the following ways:
- Points – coordinates within an area, which establish a distinct fixed point.
- Lines – a one-dimensional line used to represent linear features. Lines can also be drawn between two points to measure distances.
- Polygons – polygon data is often used to represent areas within the site, outline perimeters, and provide insights into geographical features.
Attribute data often supports vector and raster data by describing spatial features at a particular moment in time. A common example is aspects of the surrounding site environment. Vector and attribute data see lots of use in civil engineering, urban planning, and infrastructure development projects.
2.Satellite Imagery and Raster Data
Raster data, also known as grid data, is commonly used in satellite imaging to support the analysis of gradients, create heatmaps, and perform risk assessments over large areas. Raster data can be broken into two categories:
- Continuous data – features a fixed reference point from which grid cells change gradually. For instance, when creating an elevation model, you would measure each grid cell against sea level.
- Discrete data – grid cells feature specific values defined within a specific class.
A slight disadvantage of raster data is that it can blur and distort when enlarged. On the other hand, vector data is perfectly scalable.
3.Point Clouds
A collection of data points, each with an X, Y, and Z coordinate to tie it to a real-world location. When put together, a point cloud creates a 3D digital rendering of an environment. The main drawback of point cloud data is that it requires a great deal of processing power and storage.
Point clouds have only really come to the fore in the last couple of decades, as surveying equipment technology has advanced to the point where millions of individual data points can be captured in a matter of minutes. Modern laser scanners create detailed 3D models of entire areas and on-site structures by bouncing laser beams off surfaces and measuring the distance to each point.
Methods of data collection
There are many ways to go about collecting geospatial data, which are often linked to measurement methods and unique aspects of the project. Chief among these is to have an expert surveyor physically go to the site and conduct a field survey. Here, modern technologies are utilised to achieve highly accurate measurements. Total stations use cutting-edge Electronic Distance Measurement (EDM) units to deliver distance, elevation, and angle measurements.
Another method for gathering geospatial data is to use a GPS or GNSS system, which sends signals to satellites to determine the user’s location irrespective of weather conditions. These solutions also provide insight into location features through satellite imaging. Quality GNSS systems consist of a receiver, data collector, base station, and accessories.
Geospatial information systems (GIS) capture, store, analyse, and present geospatial data for use by surveyors. There are various software bundles designed to streamline workflows that deal with geospatial data, including Trimble Access and Trimble RealWorks.
Finally, it is possible to collect geospatial data using remote sensing (RS) devices such as drones. Leading survey drones can achieve efficient data collection for aerial mapping, hydrographic, and LiDAR applications, depending on the product.
Using geospatial data
Accurate and comprehensive geospatial datasets are the end goal of many on-site activities, as they inform future stages of a project. One way geospatial data can be used for construction and architectural projects is in Building Information Modelling (BIM). Using laser scanners for BIM can be complex, as it must include information relating to architectural design, material specifications, and structural engineering. All of these areas can be covered by geospatial data.
Additionally, gathering and analysing multiple types of geospatial data in combination enables surveyors to map large areas in great detail. Not only is this useful for planning the early stages of a project, but it also helps conduct thorough risk assessments to ensure the safety of those on site. Establishing features like elevations and expected weather conditions also allows surveyors to come to site with the equipment they need.
Leading survey equipment for geospatial data collection
It’s important to consider what kind of geospatial data will be necessary for your project, as this will dictate the type of equipment you need. Your solutions should also integrate with any existing workflows to ensure data can be transferred off-site without issue.
GNSS systems
A Global Navigation Satellite System (GNSS) uses various satellite constellations to provide global positioning and navigation data in real time. Leading GNSS receivers like the Spectra SP100 guarantee a strong connection despite uneven terrain or challenging conditions. This is enabled by an IMU tilt-compensation feature, with high-performance guaranteed through the Z-Blade GNSS engine and advanced error-correction technologies using 672 channels with multi-signal tracking.
While GPS and GNSS systems can both gather geospatial data, the latter is far more accurate and reliable as it makes use of multiple satellite constellations. This is the main factor when deciding is GNSS better than GPS for measuring and data collection, although it’s also worth considering which solution works for your budget.
Handheld laser scanners
Any high-performance 3D laser scanning solution will be ideal for gathering geospatial data. However, handheld scanners offer the added flexibility needed to map complex structures. The RS10 handheld laser slam scanner features a 4th-generation GNSS antenna to deliver Real-Time Kinematic (RTK) positioning with a sub-3cm accuracy. This equipment is a powerful solution for producing detailed 3D scans both indoors and outdoors.
Another powerful handheld scanning solution is the FJDynamics S2 LiDar, which creates reliable point clouds using a combination of VIO and SLAM algorithms. Point clouds are also georeferenced, and this equipment can be adapted to suit any use case. If you need a mounted laser scanner, the Trimble X9 offers leading accuracy, range, scan times, and sensitivity so surveyors can gather the data they need faster than ever before. The auto-calibration and self-levelling ensure on-site accuracy with minimal user interaction.
Total stations
Many surveying professionals use total stations to record and process geospatial data, and for good reason. Total stations combine multiple tools into one precise, efficient system. Modern total stations, such as the Trimble S9 Robotic Total Station, have impressive measurement capabilities and demonstrate high performance in even the most challenging conditions. This can be applied to construction layout, land surveys, mapping, and monitoring structural movement over time.
There are also variations in total stations, allowing professionals to pick the product best-suited to generating the type of data demanded by the project. The Trimble X12 Scanning Total Station uses additional scanning capabilities to provide detailed site context. As a result, approaches to data collection can be adapted at a rapid pace to ensure high-quality datasets.
A significant aspect of Trimble total stations is that, when you get back to the office, Trimble Business Centre software enables the processing of various types of geospatial data. This is further supported by Trimble Alltrak, which keeps surveyors up-to-date on maintenance and integration requirements.
Data collectors
If the name wasn’t enough of a giveaway, surveying professionals can use these pieces of survey equipment to collect all kinds of data on-site. A leading example that’s available through the SEP shop is the Trimble TSC5 data collector. As a device that combines reliability and high-performance, the TSC5 is the perfect option for accurate data collection in everyday surveying tasks. It also pairs with Trimble Access software to support data analysis. Key features of the TSC5 include:
- 13MP resolution camera
- Android 10 operating system combined with 2.2 GHz processor
- 4 GB of memory and 64 GB of storage
- Compatibility with external Trimble GNSS
- Ergonomic design and backlit alphanumeric keyboard
Solutions like the Trimble TDC6 data collector can pair easily with a GNSS receiver or onboard total station controller to act as a GIS collector. This product is a great example of how data collectors can integrate with various software for increased accuracy, data analysis, and collect real-world visualisation data in real time.
A cutting-edge data collector is essential to streamline workflows and reliably capture field data for further analysis. The Trimble TSC7 data collector uses leading technologies to create complete sets of geospatial intelligence based on accurate data points. As is the case with many data collectors, the TSC7 comes with an impressive internal memory and processing power to support the collection of large geospatial datasets.
Which database is best for geospatial data?
To make use of geospatial data, you need a database that can handle the storage, protection, and access of it. Traditionally, you’d have to physically connect your equipment and storage devices, but nowadays, the most efficient workflows utilise cloud storage. Uploading and downloading from the cloud is a massive time-saver. Trimble Connect Software is a great example of a solution that enables the uploading of point clouds on the move, such as when driving back from site.
Your supplier for data collection equipment
Geospatial data is more than just maps, it’s the backbone of decision-making in everything from urban planning and civil engineering to construction and surveying. With the right tools, like total stations, laser scanners, and data collectors, professional surveyors can collect geospatial data with unparalleled precision.
The SEP range includes geospatial survey equipment from leading brands, available to hire and purchase. This includes the likes of Spectra, Trimble, Leica, Faro, and more, who have spent years developing technologies to record geospatial measurements and catalogue the data.
Methods of collecting, storing, and analysing geospatial data are constantly evolving. If you’re unsure about how to get the most out of your equipment, don’t hesitate to get in touch.