Classification of Airborne Laser Scanning data

Classification Schemes

ASPRS LiDAR Classification Scheme (US/International)

This table summarizes the ASPRS (American Society for Photogrammetry and Remote Sensing) standard classification codes used in LiDAR point cloud data according to LAS Specification 1.4 - R16.

Value	Meaning
0	Created, Never Classified
1	Unclassified
2	Ground
3	Low Vegetation
4	Medium Vegetation
5	High Vegetation
6	Building
7	Low Point (Noise)
8	Reserved
9	Water
10	Rail
11	Road Surface
12	Reserved
13	Wire - Guard (Shield)
14	Wire - Conductor (Phase)
15	Transmission Tower
16	Wire-Structure Connector
17	Bridge Deck
18	High Noise
19	Overhead Structure
20	Ignored Ground
21	Snow
22	Temporal Exclusion
23–63	Reserved
64–255	User Definable

AdV LiDAR Classification Scheme (Germany)

This table summarizes the AdV standard classification codes according to Produkt- und Qualitätsstandard für 3D-Messdaten v1.3 (27.03.2025).

According to the description it is based on the ASPRS LAS 1.4 (R11) standard and is compatible with LAS 1.2+.
It defines hierarchical classes for LiDAR point clouds, allowing refinement from coarse to detailed categories.

Value (Lvl1)	Value (Lvl2)	Meaning
0	0	Created, never classified
1	1	Unspecified points
2	2	General ground points
2	9	Water surface points
2	10	Rail bed points
2	11	Road surface points
2	21	Ground excluding basements
2	22	Verified ground points
2	24	Basement/light well points
7	7	Low noise points
12	12	Overlap points
18	18	High noise points
20	20	Non-ground points
20	19	General vegetation
20	3	Low vegetation (<1.5 m)
20	4	Medium vegetation (1.5–8 m)
20	5	High vegetation (>8 m)
20	6	Building points
20	28	Building installations
20	27	General structure points
20	17	Bridge deck points
20	26	Bridge foundation points
20	25	Hydraulic structure points
20	23	Power infrastructure points
20	13	Shield wire points
20	14	Conductor wire points
20	15	Transmission tower points
20	16	Transmission infrastructure
29	29	Synthetic points
29	8	Synthetic water points
29	30	Synthetic surface points
31	31	Filled points from ALS

Legacy LiDAR Classification Scheme (Lower Saxony, until 2020)

This table shows the classification scheme used in Lower Saxony prior to 2021.

Value	Meaning
2	Ground points (general), DTM-relevant
7	Outliers (noise, low/high points), not delivered
8	Measured water points
11	Synthetic water points (2 m grid)
12	Subsurface/basement points (e.g. ramps, shafts, pools)
13	Non-ground points, DSM-relevant
15	Other/unclassified points
20	Overlap points (all, excluding outliers)
22	Overlap ground points (unchecked)
23	Overlap non-ground points (unchecked)
25	Overlap other points (unchecked)
26	Overlap outliers (unchecked)
27	Overlap subsurface points (unchecked)

Conversion

AdV to ASPRS

unchanged

0 - 0
1 - 1
2 - 2
3 - 3
4 - 4
5 - 5
6 - 6
7 - 7
9 - 9
10 - 10
11 - 11
12 - 12 (overlap flag)
13 - 13
14 - 14
15 - 15
16 - 16
17 - 17
18 - 18

changed

8 - 9 (synthetic flag)
19 - 5
20 - 1
21 - 2
22 - 2
23 - 1
24 - 20
25 - 1
26 - 1
27 - 6
28 - 6
29 - 1 (synthetic flag)
30 - 1 (synthetic flag)
31 - 1

Problems:

Classes 19 to 22 were newly defined in ASPRS Revision 14 (2019), but were defined differently in the meantime by AdV although they were reserved.
Class 8 is used for synthtic water points by AdV, but ASPRS defined it as Model key-Points, which might be used similar but does not necessarily mean the same. In the meantime class 8 is reserved.
class 24 (basement) has no direct translation, most similar would be class 6 (building), class 2 (ground) or 20 (ignored ground)
class 19 (vegetation) has multiple translations (3/4/5 - low/medium/high vegetation), it is converted to high vegetation here which could be separated based on Height above ground.

Legacy to ASPRS