Lidar Base Specification: Tables

By NGP Standards and Specifications

Lidar Base Specification 2022 rev. A

Tables referenced in the Lidar Base Specification 2022 rev. A online

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Table 1: Aggregate nominal pulse spacing and density.

Table 2: Relative vertical accuracy for light detection and ranging swath data.

Table 3: Land cover classes.

Table 4: Absolute vertical accuracy for light detection and ranging data and digital elevation models.

Table 5: Minimum light detection and ranging data classification scheme.

Table 6: Minimum digital elevation model cell size.

Table 1: Aggregate nominal pulse spacing and density.
Quality level	Aggregate nominal pulse spacing (m)	Aggregate nominal pulse density (pls/m²)
QL0	≤0.35	≥8.0
QL1	≤0.35	≥8.0
QL2	≤0.71	≥2.0
QL3	≤1.41	≥0.5

Table 2: Relative vertical accuracy for light detection and ranging swath data.
Quality level	Smooth surface repeatability, RMSD_z (m)	Swath overlap difference, RMSD_z, (m)
QL0	≤0.03	≤0.04
QL1	≤0.06	≤0.08
QL2	≤0.06	≤0.08
QL3	≤0.12	≤0.16

Table 3: Land cover classes.
Class number	Land cover class or description	Previous reporting group	Current reporting group
1	Clear or open, bare earth, low grass; for example, sand, rock, dirt, plowed fields, lawns, golf courses	FVA	NVA
2	Urban areas; for example, tall, dense man-made structures	SVA
3	Tall grass, tall weeds, and crops; for example, hay, corn, and wheat fields	SVA	VVA
4	Brush lands and short trees; for example, chaparrals, mesquite	SVA
5	Forested areas, fully covered by trees; for example, hardwoods, conifers, mixed forests	SVA
6	Sawgrass	n/a	n/a
7	Mangrove and swamps	n/a

Table 4: Absolute vertical accuracy for light detection and ranging data and digital elevation models.
Quality level	RMSE_z (nonvegetated) (m)	NVA at the 95-percent confidence level (m)	VVA at the 95th percentile (m)
QL0	≤0.050	≤0.098	≤0.15
QL1	≤0.100	≤0.196	≤0.30
QL2	≤0.100	≤0.196	≤0.30
QL3	≤0.200	≤0.392	≤0.60

Table 5: Minimum light detection and ranging data classification scheme.
Code	Description
1	Processed, but unclassified
2	Bare earth
7	Low noise
9	Water
17	Bridge deck
18	High noise
20	Ignored ground (typically breakline proximity)
21	Snow (if present and identifiable)
22	Temporal exclusion (typically nonfavored data in intertidal zones)

Table 6: Minimum digital elevation model cell size.
Quality level	Minimum cell size (m)	Minimum cell size (ft)
QL0	0.5	1
QL1	0.5	1
QL2	1	2
QL3	2	5