From ObjectVision

A Value Type indicates the kind of values that can be stored in parameters and attributes.

• A unit determines a set of comparable values (= domain in the terminology of C.J. Date) and must be related to a specific Value Type.
• A parameter stores one element value, for which the value type is determined by the values unit of the parameter.
• An attribute is implemented as an array of elements of a specific value type. The value type of these elements is determined by the values unit of the attribute.The location of these elements is implicitly determined by their position in the array.The set of valid locations and the type of these location elements is determined by it's domain unit.

Examples of the usage of the value type Float32

unit<Float32>      Meter:             Expr = "BaseUnit('m', Float32)";
parameter<Meter>   RealWagonLength:   Expr = "value(22, Meter)";
parameter<Float32> MarklinHO:         Expr = "Float32(1.0 / 87.0)";
parameter<Meter>   ScaledWagonLength: Expr = "MarklinHO * RealWagonLength";

Available value types in the GeoDMS

Name	Description	Size	MinValue	MaxValue	MissingValue	CanBeDomainUnit	NumericGroup	SignedGroup	PointGroup	Version
bool	boolean	1 bit	false	true	n/a	X
uint2	unsigned integer	2 bits	0	3	n/a	X
uint4	unsigned integer	4 bits	0	15	n/a	X
uint8	unsigned integer	1 byte	0	0xFE ( 254 )	0xFF ( 255 )	X	X
uint16	unsigned integer	2 bytes	0	0xFFFE ( 65534 )	0xFFFF ( 65535 )	X	X
uint32	unsigned integer	4 bytes	0	0xFFFFFFFE ( 4294967294 )	0xFFFFFFFF ( 4294967295 )	X	X
uint64	unsigned long integer	8 bytes	0x0000000000000000	0xFFFFFFFFFFFFFFFE	0xFFFFFFFFFFFFFFFF	X	X	X		Since 5.75
int8	signed integer	1 byte	0x81 ( -127 )	0x7F ( 127 )	0x80 ( -128 )	X	X	X
int16	signed integer	2 bytes	0x8001 ( -32767 )	0x7FFF ( 32767 )	0x8000 ( -32768 )	X	X	X
int32	signed integer	4 bytes	-2147483647 (0x80000001)	2147483647 (0x7FFFFFFF)	-2147483648 (0x80000000) Also -9999	X	X	X
int64	signed long integer	8 bytes	0x8000000000000001	0x7FFFFFFFFFFFFFFF	0x8000000000000000	X	X	X		Since 5.75
float32	floating point	4 bytes	-3.4E+38 (7 digits)	3.4E+38 (7 digits)	-9999.0		X	X
float64	floating point	8 bytes	-1.7E+308 (15 digits)	1.7E+308 (15 digits)	-9999.0		X	X
spoint	two int16 coördinates (row, col)	4 bytes	(MinValue of int16)^2	(MaxValue of int16)^2	(MissingValue of int16)^2	X			X
wpoint	two uint16 coördinates (row, col)	8 bytes	(MinValue of uint16)^2	(MaxValue of uint16)^2	(MissingValue of uint16)^2	X			X	Since 5.77
ipoint	two int32 coördinates (row, col)	8 bytes	(MinValue of int32)^2	(MaxValue of int32)^2	(MissingValue of int32)^2	X			X
upoint	two uint32 coördinates (row, col)	8 bytes	(MinValue of uint32)^2	(MaxValue of uint32)^2	(MissingValue of uint32)^2	X			X	Since 5.77
fpoint	two float32 coördinates (x, y)	8 bytes	(MinValue of Float32)^2	(MaxValue of Float32)^2	(MissingValue of Float32)^2				X
dpoint	two float64 coördinates (x, y)	16 bytes	(MinValue of Float64)^2	(MaxValue of Float64)^2	(MissingValue of Float64)^2				X
string	sequence of chars	2*sizeof(UInt32)+n*sizeof(uint8)		0x255 0x255 0x255 0x255	'null'