6. Appendix A – Residential Examples
Overview of flight paths
6.1 Home with No Obstructions Example 1
This is the simplest project to map. Only two flight paths are needed because there are minimal obstructions to affect the proposed arrays. The goal will be to map the full context of the site, and then the roof’s details.
Image Range: 100 – 125
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~60 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees.
6.2 Home with No Obstructions Example 2
The site has no trees at the height of the roof plane or taller, and the rooftop obstructions are visible and centralized. Finally, there are only a handful of roofplanes that are fairly simply shaped. Only two POIs are needed.
Overview of flight paths
Image Range: 100 – 125
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~60 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
Overview of flight paths
6.3 Home with Some Obstructions Example 1
Similar to a home with no obstructions, this entails just two flight paths. Additional attention is required for trees to the south and vents on the roof, but with sufficient overlap the imagery will pick up these details. To accomplish this, increase the image range as compared to the prior example.
Image Range: 125 – 150
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~70 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
6.4 Home with Some Obstructions Example 2
Some obstruction may refer to the surrounding buildings and vegetation. While the house itself has few vent pipes and a fairly simple roof structure, the trees around it may cause shade. Two detailed POIs may be necessary to capture all potential implications for the site.
Overview of flight paths
Image Range: 200 – 225
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~70 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees.
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees.
Overview of flight paths
6.5 Home with Many Obstructions Example 1
This home has significant vegetation aligning the house and in the southeast of the property. A context POI that includes all of the vegetation, with the home in the middle, is a key first flight. Subsequent detailed flights are focused on mapping all relevant vegetation.
Image Range: 200 – 250
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~70 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees
Notably, if tree density is sparser (e.g. fewer leaves and/or thin branches), it is important to record the heights of trees using the drone’s altitude. Hover the drone at the top of the tree and take a screen shot on your smart phone or table of the flight app to document altitude and location.
6.6 Home with Many Angular Roof Planes
Homes with numerous roof planes of varying shapes can be a nuisance to measure, let alone fit solar onto. These properties require multiple detailed flight paths to capture the nuance of all roof shapes. Be cognizant of nearby homes potentially causing shading as well, hence a larger context flight may be needed.
Overview of flight paths
Image Range: 175 – 225
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~60 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
6.7 Home with Surrounding Very Tall Trees
Large trees near homes may cause significant shading and therefore require a few adjustments. First, the context flight should expand to include all trees that can impact the solar array. These are trees usually on the east, west and south sides of the property. Secondly, the context POI’s height must be the same height of the tallest trees.
Overview of flight paths
Image Range: 200 – 225
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~120 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
Overview of flight path
The pilot can fly a second context flight around highly impactful trees if desired. In this case, another POI is needed for trees in the east of the property.
POI 4 – Context flight: ~120 feet AGL, camera angle ~45 degrees
Overview of flight paths
6.8 Residential Property with Multiple Structures
Some residential properties have multiple structures on the same site. This can include a detached garage, pool house, barn or shed. It can also involve a home that has multiple segments. Assuming the structures are all within a reasonable distance, pilots should fly the site as one, large property. Homeowners will typically want to explore putting arrays on each structure. Furthermore, PV designers will want to consider the total potential system size across all proposed arrays. For these projects, a very large context flight is necessary. Subsequently, treat each structure as its own building by flying detailed flight(s) around them.
Image Overview: 200 – 250
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~70 feet AGL or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The middle of the cluster of buildings should be in the camera’s frame for every shot. The point of interest is the middle of the cluster. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
POI 4 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
POI 5 – Detailed flight: ~10 feet above building / obstructions, camera angle ~35 degrees
6.9 Urban / Dense Neighborhoods & Rowhouses
Residential properties in urban or dense areas require careful planning. Pilots often must consider a variety of obstructions in the same property, including nearby buildings, trees and rooftop equipment. Each of these will impact the potential production of an array, and therefore must be mapped. Consider this city neighborhood and the rowhouse with the red pin:
Similar properties to this example include rowhouses, brownstones, small apartment complexes and any urban buildings close together.
An effective way to map these properties is to start with a very large context flight, following by small and targeted detailed flights just hovering above the roof or obstruction tops. Focusing in on quality oblique imagery will also help render a good looking 3D model.
Image Overview: 200 – 250
Overlap: ~90%
Speed: 2-5MPH, or taking a picture every 2-4 seconds.
POI 1 – Context flight: ~100 feet AGL, or 10 feet above the tallest obstruction, with camera angle at ~45 degrees. The entire building should be in the camera’s frame for every shot. The point of interest is the middle of the building. The flight path’s radius should be set by including (1) the entire building and (2) any surrounding obstructions that could cause shadows on the building (eg vegetation, trees, surrounding buildings). The radius can be set in the camera viewer.
POI 2 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees
POI 3 – Detailed flight: ~10 feet above building / obstructions, camera angle ~30 degrees
Overview of flight paths