LAS Format Elements¶

On this page, elements and attributes of LAS Format 1.0 and 1.1 are compared.

Data Types¶

Both versions of LAS Format Standard define and use the same set of data types and their sizes:

1 byte
- char (int8_t)
- unsigned char (uint8_t)
2 bytes
- short (int16_t)
- unsigned short (uint16_t)
4 bytes
- long (int32_t)
- unsigned long (uint32_t)
8 bytes
- double - double precision floating-point number (64-bit) as defined in IEEE 754 Standard

#	Element	LAS 1.0	LAS 1.1
1	File Signature (“LASF”)	int8_t[4], required
2	File Source ID		uint16_t, required
3	Reserved	uint32_t	uint16_t
4	GUID data 1 (Project ID)	uint32_t
5	GUID data 2 (Project ID)	uint16_t
6	GUID data 3 (Project ID)	uint16_t
7	GUID data 4 (Project ID)	uint8_t[8]
8	Version Major	uint8_t, required
9	Version Minor	uint8_t, required
10	System identifier	int8_t[32], required
11	Generating software	int8_t[32], required
12	Flight date Julian / Day of Year	uint16_t
13	Year	uint16_t
14	Header size	uint16_t, required
15	Offset to data	uint32_t, required
16	Number of variable length records	uint32_t, required
17	Point data format ID (0-99)	uint8_t, required
18	Point data record length	uint16_t, required
19	Number of point records	uint32_t, required
20	Number of points by return	uint32_t[5], required
21	X scale factor	double, required
22	Y scale factor	double, required
23	Z scale factor	double, required
24	X offset	double, required
25	Y offset	double, required
26	Z offset	double, required
27	Max X	double, required
28	Min X	double, required
29	Max Y	double, required
30	Min Y	double, required
31	Max Z	double, required
32	Min Z	double, required
Total number of bytes:		227	227

Type specifier of the form of type[N] where N is a number, represents array of N elements of type.

The table below is based on definition of Point Data Record Format 0 and it does not include what’s specified Point Data Record 1.

#	Element	LAS 1.0	LAS 1.1
1	X	int32_t, required
2	Y	int32_t, required
3	Z	int32_t, required
4	Intensity	uint16_t
5	Return number	3 bits (0,1,2), required
6	Number of returns (given pulse)	3 bits (3,4,5), required
7	Scan direction flag	1 bit (6), required
8	Edge of flight line	1 bit (7), required
9	Classification	uint8_t	uint8_t, required
10	Scan angle rank (-90 to +90)	int8_t, required
11	File Marker / User Data (1)	uint8_t
12	User Bit Field / Point Source ID (2)	uint16_t	uint16_t, required

FileMarker from 1.0 has been renamed to User Data in 1.1 and is available for any use.
User Bit Field from 1.0 has been renamed to Point Source ID in 1.1 and marked as required.