Choosing the Right Orthoimagery Resolution
Orthophotography can vary greatly in accuracy and pixel resolution. Pixel resolution (a single point in a graphic image) refers to the actual distance on the ground each pixel represents in the orthophotography.
For example, one-foot pixel resolution means each pixel in the image covers one foot on the ground. Some common resolutions include three-inch, six-inch, and one-foot. The higher the resolution (i.e., three-inch per pixel), the greater the visible detail. |
12" Resolution Orthophotography
Generally captured at higher altitudes, 12-inch resolution orthophotography provides a greater scale at a lower resolution. It is a cost effective way to collect large-area projects in time constrained environments.
- Key identifiable features:
-Paved Roads
-Airfields
-Railroads
-Buildings
-Hydrology
-Forested Areas
-Quarries
- Typical uses:
-Regional/rural planning
-Tax assessment
-Building counts
-Change detection
-Land cover trends
-Watershed management
-Forestry management
-Highway mapping
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6" Resolution Orthophotography
Six-inch resolution orthophotography is an increasingly standard resolution option. The 6" resolution ortho product yields greater accuracy and greater detail, as well as better inherent positional accuracy.
- Key identifiable features:
-Roads - Paved and unpaved
-Parking Lots and Driveways
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Lakes, ponds, rivers and streams
-Culverts and headwalls
-Property line fences
-Utility Poles
- Typical uses:
-State planning
-Land boundaries
-Planimetric
-Pervious/impervious surface
-Feature identification
-Stormwater management
-Natural resource management
-Irrigated/non-irrigated land
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3"-4" Resolution Orthophotography
CAptured at lower altitudes, High resolution orthophotography has the greatest resolution, providing a product that captures the greatest visible detail and has the best innate positional accuracy available.
- Key identifiable features:
-Utilities - fire hydrants, manholes, catch basins
-Power and light poles
-Billboards and traffic signs
-Curbs and gutter
-Transportation paint lines
-Single trees and shrubs
-Golf course - tees, greens, fairways, sandtrap
- Typical uses:
-Urban planning and zoning
-Contour development
-Asset management
-3D Modeling
-Utility / pipeline mapping
-Land development,
-Transportation / corridor projects
-Volumetric analysis
-Civil engineering
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