8. Appendix C - Ground Mounts Examples
8.1 Open Field / Landfill, with minimal vegetation
Open fields, landfills and other ground mount projects do not require POIs because typically they do not possess vertical features that can pose shading. A simple rasterized flight path will suffice. POIs may be needed if trees surround the perimeter of the property and the pilot needs to capture them in detail for shading analysis purposes.
8.2 Open Field / Landfill, and mapping vegetation
Follow instructions for 5.1 above, except add a 50-200 foot offset (ie distance from the edge of the (proposed) array into the surrounding vegetation). This will facilitate proper 3D mapping of the perimeter vegetation. The shorter the trees the smaller the offset and vice versa. For example, projects in the Pacific Northwest, where trees are easily 150 feet, will require a much larger offset than projects in the Mojave Desert. In DroneDeploy’s app, utilize grid 3D mode or “enhanced 3D”. Overlap can be 70%, plus or minus 5%.
Here is an example of those settings:
8.3 Carports
Mapping for a proposed carport depends on the surrounding obstructions. Typically, the parking lot or field where the carport will be built doesn’t have complicated features. In that case, a simple rasterized flight path like an open field is sufficient.
Overview of flight paths
However, POIs should be used in two unique cases. First, if the objective is to map any vertical features, like curb heights, posts and lighting, detailed POIs should be flown around those features. For this case, a POI or rasterized flight is sufficient for the context flight.
The second unique case is if the surrounding area has notable shading implications. For example, a carport has been proposed for the lot to the southwest of the tower. Detailed POI (ie flight #2) will adequately map the parking lot’s features. Yet, a larger context POI (ie flight #1) is required to render the tower in order to run an accurate shading analysis.
Image Range: 300 – 350
Overlap: >80%
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: ~50 feet AGL, camera angle ~45 degrees
8.4 Project Mapping from different perspectives; best for Housing Authorities and Local Zoning Rules
A major benefit of using drone imagery to construct 3D models is that the 3D models can show perspective from any angle of a site. This is especially helpful when pitching local housing authorities, school districts or any group with strict zoning rules.
Mapping the property should follow whatever rules as given by the site features. For example, to show perspective for a commercial building, just follow the guidelines for mapping that type of commercial building.
The below example is of a ground mount project. In this case, the homeowners in the northern part of the image wanted confidence that they weren’t going to be staring down at an array at the southern part of the image. Therefore, the pilot mapped the entire expanse between them.
To show full perspective, the pilot designed the flight path to start in the backyard of the homeowners - see below picture. To show this degree of perspective for a residential or commercial project would entail taking additional POIs to capture more oblique imagery.
Overview of flight paths
8.5 Ground Mount + Large Obstruction Example 1
These projects combine flight paths from both rooftop projects with many obstructions and ground mount projects. The context flight can be a large POI or a rasterized flight path, depending on the topography and obstructions.
Image Range: 400 – 500
The main objective is to fly several detailed POIs at different altitudes around the tower:
Here are the DroneDeploy settings for the rasterized context flight if this is preferred instead of the context POI:
8.6 Ground Mount + Large Obstruction Example 2
Overview of flight paths
Follow the same guidelines as in the prior example. Of note, the context flight is a rasterized flight (ie flight #1) with less overlap because (a) it is an open field, (b) the notable obstructions are either to the north and therefore not relevant (ie trees) or have detailed POIs flown around them, and (c) a context POI would be unnecessarily large, while a rasterized flight can better accommodate non-circular properties.
Image Range: 400 – 500
Here is the DroneDeploy flight path and settings for the context flight:
