Tag: surveying

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Using Trimble R10 to Validate Photogrammetry Products

by Ryan Wicks | January 2023

Introduction

RTK GNSS receivers are one of many tools that are leveraged for conducting survey work, and with the addition of unoccupied aircraft systems (UASs) to supplement GNSS receivers, theodolites, and the like, new survey techniques are being used and further refined to collect data about the landscape and physical features of interest. A common workflow is to have several ground control point (GCP) markers distributed throughout an area of interest that is to be surveyed, to survey those few GCP locations with a RTK GNSS receiver or some other ground survey tool, and then fly a drone to collect aerial imagery of the entirety of the area of interest; so long as a significant portion of the images that the drone took have the GCP markers visible in the images, then the surveyed GCPs can be used to constrain a photogrammetry reconstruction from the drone images to have a similar level of accuracy throughout the survey area. I’ve touched on this technique in a few of my other articles. This can be an effective technique for attaining a high spatial accuracy over a large area at a resolution that wouldn’t be possible without instrumentation like LiDAR. While this workflow is sufficient in many cases, there is an additional role in this process that RTK GNSS receivers can play: assessing the accuracy of final photogrammetry products.

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Mapping the UMass Amherst Campus Using UAS Aerial Imagery 2023

By Ryan Wicks | 25 Jun 2023

Introduction

If you’ve visited the UMass Amherst campus occasionally in the last 10 years you may have noticed dozens of new construction projects of various sorts popping up all over the campus; new academic buildings, solar panel parking canopies (https://www.umass.edu/sustainability/climate-change-energy/solar-energy/2017-solar-projects), and geothermal well drilling, just to name a few. To coordinate these efforts effectively, up-to-date information – specifically GIS data – is quite helpful. Not only does the UMass Amherst Physical Plant leverage drones and Trimble R10 RTK to regularly survey progress on construction projects, but they also host a campus-wide GIS working group whose focus is to promote and leverage the power of GIS data, tools, and ancillary equipment to provide highly detailed, highly accurate, current information to any departments and decision makers in the UMass network.

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Surveying a Retaining Wall

 

UMass BCT Graduate Student Brett Barnard can be seen here operating the Trimble TX8 3D Scanner with Senior Andrew Smith and Sophomore Leo Minniti to survey and analyze a retaining wall on the Amherst campus. They plan to scan the entire wall in both Fall and Spring to obtain multiple 3D point clouds of the area for surveying and mapping purposes. Continue reading “Surveying a Retaining Wall”

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Validating Water Surface Elevation for a Citizen Science Project in New Hampshire

By Merritt E. Harlan

How and why lake volumes change over time remains a largely unknown question globally. Factors such as precipitation, water table height, evaporation, and human impacts such as lake level drawdown can impact lake volumes over time, potentially resulting in changes in water supply and lentic ecosystems. To learn more about changes in lake volumes at a global scale, the project “Lake Observations by Citizen Scientists and Satellites” (LOCSS) pairs satellite imagery, which can detect lake area over time, with simple lake gauges that everyday citizens can read and collect data from. With the changes in height read from the lake gauge paired with the changes in lake surface area, we can better assess changes in lake volume over time. Continue reading “Validating Water Surface Elevation for a Citizen Science Project in New Hampshire”

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Surveying Instrumentation in Mangrove Forests in Puerto Rico

By Pedro I. Matos Llavona

It is well known that sea level is rising and will cause significant shoreline adjustments around the globe. This makes the art of measuring sea level a critical skill for coastal scientists. For precise and accurate measurements, not only it is necessary to understand the functionality of the instruments we use, but also the reference frame to which all our measurements are fixed to, better known as datums. Fortunately, high end technology such as Global Navigation Satellite Systems (GNSS) can help us measure elevation up to 2 cm precision. This high level of precision requires complex processes. Thankfully, there is instrumentation capable of reaching high precision within a short period of time – the Trimble® R10 GNSS system.

Frances Griswold (PhD Candidate) surveying bridge near our deployed instruments mooring in Vieques, PR

 

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