At the UMass Amherst campus we regularly use UAS to conduct surveys of key infrastructure; whether it be to monitor and document stages of new construction on campus or to survey and inspect existing infrastructure. One of our more recent additions to our array of capabilities is the capacity to develop thermal orthomosaics from long-wave infrared (LWIR) imagery. This can help us map heat sources and thermodynamic processes of buried infrastructure, or look at heat loss in structures.
In a recent survey project we surveyed roofing of some campus buildings to inspect for suspected leaks. In general, if water leaks into a roof if can compromise the insulation of the building and conduct heat more readily. In the winter time when the outside temperature is significantly cooler than the inside temperature areas of compromised insulation will show up as relatively hotter than the surrounding area on a surface because it is conducting the heat from the inside to the outside more readily.
Working with thermal imagery can be especially tricky for several reason. Unlike many other types of aerial imagery which captures images of reflected radiation, thermal images are images of emitted radiation, that is to say radiation emitted by warm objects. This radiation depends on the emissivity of a material, which is the proportion of how much energy it emits at a given temperature compared to an ideal “black-body” radiator. Consequently all images have to be adjusted and tuned to look at specific materials, and be tuned to compensate for reflected radiation from the background (which is the sky in this case), as well radiation signal loss through the atmosphere due to attenuation by both water and carbon dioxide.
Additionally, just as with orthomosaics constructed from red-green-blue images, we use ground control points (GCPs) to help constrain the reconstruction of LWIR thermal orthomosaics. GCPs for thermal surveys need to be designed slightly differently; while GCPs used for surveys in the visible bands need to have “color” contrast with respect to the ground on which they are placed, GCPs placed for thermal surveys need to have either temperature or emissivity contrast with the ground on which they are placed.
The use of an RTK GNSS receiver or other accurate survey tool allows us to measure this GCPs to within a few centimeters, and consequently a similar level of accuracy can carry over to final data products. This is important so that our thermal orthomosaics can align accurately with RGB orthomosaics, as well as other data layers such and surveys that might show areas of infrastructure; this enables us to relate the thermal signals we see to specific structures or features measured by other means.
When you walk around in public spaces carrying a Trimble R10 RTK over your shoulder, you get asked a lot of questions!
For the past two summers, myself and a group of researches have used the Trimble R10 to take location and elevation measurements of landscape features in salt marshes throughout Massachusetts. Sometimes we are at Audobon sites sharing space with birders, sometimes we are near roads or in what seems like someone’s backyard, and sometimes we are just off of someone’s favorite walking path. Regardless of who we cross paths with – birder, driver, homeowner, or hiker – we always get asked about the R10 because it looks so sleek yet complex! Sometimes we are asked “What are you doing?” or “What is that?” or our favorite, “Are you making a movie?!”.
Undergraduate students in BCT and other programs in collaboration with the UMass Amherst Physical Plant assisted the commencement planning team with layout for the main graduation event. Commencement planning for thousands of students takes a village or at least the Physical Plant at UMass Amherst. One of the people responsible for coordinating the layout for events is Surveyor and GIS Administrator Carl Larson. Carl has been in charge of staking out commencement planning for a number of years, but this year Carl has a little more help. With the help of a few students and Trimble GPS equipment, the stadium will be transformed from an athletic field to graduation for thousands of students and their parents. By using the Trimble R10, we have cut the time it takes to layout graduation by almost two-thirds.
City and regional planners have the daunting task of developing a vision for the future of both the physical, aesthetic and cultural feel of an area. This often involves engaging multiple parties that have a stake in that future, identifying convergent or divergent needs or desires of those stakeholders, identifying themes within those needs or desires, and developing not just one potential plan, but a multitude of plans that can be considered in comparison. Continue reading “Using the Trimble R10 with Drones to Develop City Models for Professional Planners”
The Wetland Assessment Program (WAP) at UMass Amherst is an ongoing research program, the main goal of which is to study wetland ecosystems and to develop better tools for monitoring and conservation of these areas. (http://www.umasscaps.org/applications/wetlands-assessment.html) Headed by Dr. Scott Jackson and Dr. Kevin McGarigal for the past decade, WAP is part of the larger Conservation Assessment and Prioritization System (CAPS). The main strategy of the program is to find and measure relationships between Landsat data – which includes land use data, elevation, slope, etc. – and both Indices of Biological Integrity (IBIs) and Indices of Ecological Integrity (IEI’s). The specific sampling and observation methods vary depending on the type of wetland system under consideration. The program has had significant success in finding meaningful and useful patterns for most wetland systems, however success with salt marsh studies has been elusive. Continue reading “Measuring Ground-Control Points for Salt Marsh Studies”