FREQUENTLY ASKED QUESTIONS
Does aerial mapping violate my privacy?
FireWatch operates its aircraft and imaging sensors almost 1 mile above ground level, which is similar to the height that Google flies their aircraft to collect images for Google Maps. FireWatch uses multispectral imaging sensors that collect invisible and visible wavelengths for scientific analysis. Objects that are not vegetation are often removed (normalized) from the maps since they are not needed.
What is the difference between LiDAR and MSI?
Aerial surveys can be done with expensive and cumbersome LiDAR sensors. LiDAR uses a laser sensor to measure and detect structures on the ground. While LiDAR is a great tool for measuring structure and volume, it does not provide any information about the health or condition of vegetation.
Due to its high cost, LiDAR is not frequently used for aerial surveys. MSI, on the other hand, is much more affordable and can generate full color 2D and 3D models that are easier to visualize and interpret than LiDAR data. The main deliverables from MSI are color image maps, vegetative indices, digital surface models (DSM) and 3D models created from stitching and processing hundreds or thousands of images.
What is Photogrammetry?
Photogrammetry is the art, science, and technology of obtaining information about the environment through processes of recording, measuring, and interpreting photographic images.
Photogrammetry is used to make precise measurements of three-dimensional objects and terrain features from two-dimensional photographs. Applications include measuring distances, heights, areas, and volumes. Photogrammetric data is used for the preparation of topographic maps, digital elevation models and orthophotographs.
Photogrammetry is used to determine the percentage of canopy cover and the planting potential with high-resolution image maps. New assessment tools can calculate biomass for carbon sequestration and heat island effect.
What are Vegetation Indices?
Spectral vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), provide an important diagnostic tool for measuring and understanding vegetative health. NDVI is diagnostic of vegetation biomass, productivity, stress, canopy fragmentation, and photosynthetic capacity. Scientists at FireWatch use proprietary algorithms to differentiate dead and dying vegetation from healthy vegetative species.
Can satellite image data be used instead?
Satellite data is very low resolution compared to aerial data collected from an airplane or drone. Satellite maps are utilized for studying very large areas such as countries and continents. Communities and cities need ultra high resolution imaging from aircraft to classify and quantify vegetation.
What is the resolution of FireWatch aerial maps?
Orthorectified image mosaics with a 3-inch spatial resolution can be generated for wide areas (1 to 150+ sq miles) using full-size aircraft. Small UAS are then utilized over specific sites to generate orthomosaics with spatial resolution of 1 cm or less for “ground truthing” aerial maps and more detailed vegetation analysis.
What is FireWatch?
FireWatch is a service that empowers homeowners to recognize wildfire risks in their community. Using aerial imagery and fuel modeling, FireWatch provides a digital early warning system to residents. With this information, homeowners can evaluate and manage their own defensible space against wildfire threats. By working together, homeowners provide a defensible space network for the entire community.
What is Remote Sensing?
Remote sensing is the science of obtaining information about ground features using aircraft, drones or satellites. Image sensors record the reflectance of surface features to help scientists “sense” structures and ground features. The scientists at FireWatch use remote sensing to create wildfire preparedness for communities.
What is Multispectral Imaging?
Multispectral Imaging (MSI) is a type of remote sensing that measures the solar radiation reflected from targets on the ground. Different objects reflect and absorb light at different wavelengths. Healthy vegetation reflects near-infrared wavelengths that are not visible to the human eye. MSI can be used to differentiate healthy vegetation from dead or dying vegetation.
What is Vegetative Fuel Modeling?
The size and cover density of vegetative fuels is a major driving force behind the destructive power of wildfires. Using an aerial fuel map of the community and image processing software, 2D and 3D computer fuel models can be created. By understanding the structure and distribution of vegetative fuels in the community, potential wildfire behavior can be modeled under different conditions. Wildfire modeling can also help further identify high-risk areas and develop a community action plan.