Our Data

What is LiDAR?

LiDAR — Light Detection and Ranging — is a remote sensing method that uses laser pulses to measure the distance between a sensor (typically mounted on an aircraft) and the surface below. By recording millions of these measurements across a survey area, LiDAR produces an extremely detailed, three-dimensional picture of the earth's surface at resolutions that traditional elevation datasets can't match.

At 1-meter resolution, each data point represents a 1m x 1m area on the ground. That level of detail matters in fixed wireless: the difference between a clear line of sight and an obstructed one can come down to a single row of trees or a roofline — things that coarser datasets at 3m or 30m resolution will miss entirely.

Digital Surface Models vs. Bare Earth

Not all elevation data is the same. There are two primary products derived from LiDAR: a Digital Terrain Model (DTM), which represents the bare earth with all above-ground features removed, and a Digital Surface Model (DSM), which represents the first surface the laser hits — including buildings, tree canopies, vehicles, and any other above-ground structures.

SightLine uses a Digital Surface Model. For fixed wireless, this is the correct choice. A signal doesn't pass through a building or a tree — it has to clear it. Using bare-earth terrain data ignores the real-world obstructions that determine whether a customer can actually be served. Our DSM captures that clutter data so the analysis reflects what your signal will actually encounter.

Source: USGS 3D Elevation Program (3DEP)

Our surface data originates from the USGS 3D Elevation Program (3DEP), a nationwide initiative to collect consistent, high-quality LiDAR coverage across the United States. 3DEP is the authoritative source for publicly available elevation data in the US and represents the most comprehensive high-resolution LiDAR dataset available at national scale.

Raw LiDAR data from 3DEP, however, is not ready to use as-is. Collection artifacts and data quality issues are common and must be addressed before the data can be relied on for accurate line-of-sight analysis.

Processing & Quality Control

Before any data enters SightLine, it goes through a processing pipeline designed to correct the most common issues found in LiDAR-derived surface models:

• No-data areas — LiDAR collection can leave gaps in coverage due to flight path limitations, water bodies, or sensor dropout. Left unaddressed, these voids produce unreliable results. We identify and fill no-data areas using interpolation techniques that maintain spatial consistency with surrounding data.
• Cloud spikes — Laser returns from clouds, birds, or other airborne objects can register as false high-elevation points in the raw data. These spikes, if left in place, would cause incorrect obstruction readings. We detect and remove outlier points that fall outside expected elevation ranges for a given area.

The result is a clean, reliable surface dataset that behaves predictably across the analysis engine.

Always the Best Available Data

LiDAR coverage is not static. New surveys are conducted regularly as part of ongoing 3DEP collection efforts, and more recent data is almost always higher quality — better resolution, more complete coverage, and fewer artifacts. We actively monitor for new and updated datasets and incorporate improvements into the system on an ongoing basis. When better data becomes available for an area, we update it.

The goal is simple: SightLine should always be running on the most accurate surface data available, so your qualification results can be trusted.