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Project Design Grid (*.WRB) Format

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The project design grid format can contain all the same data as a WRG. But it can also contain: roughness; inflow angles; turbulence intensity variation across the site; wind shear exponent and so on.

Header structure

Start Byte

Number of Bytes

Type

Description

Comments

 

 

 

 

 

0

2

unsigned short

File type

1001 = BINARY WRG – non-interleaved, uncompressed.

2

2

unsigned short

Version

Version of this type of file current = 2

4

1

byte

Horizontal units

1 = meters

5

1

byte

Vertical units

1 = meters

6

30

character

Characters describing datum projection as an EPSG code

e.g. "EPSG:32619" is the best way to specify WGS84, UTM 19

36

2

Unsigned short

Number of directions

e.g. 12

38

2

Unsigned short

Number of heights

e.g. 1

40

2

Unsigned short

Number of wind speeds

Unused(default) = 0

 

42

8

double

X min

Rectangle describing bounding grid points. Covered area is res/2 larger in all directions

50

8

double

X max

58

8

double

Y min

66

8

double

Y max

74

8

double

Resolution in X

 

82

8

double

Resolution in Y

Usually same as res X

90

2

Unsigned short

Total Number of blocks

Block descriptions start at byte 100. each block description is

92

8

byte

Unused

 

100

2

Unsigned short

Data meaning for block index 0

1 = elevation,

2 = mean wind speed

3 = A

4 = K

5 = Power

6 = Turbulence Intensity

7 = Inflow angle

8 = Probability (for wind freq table at every point)

9 = Direction

10 = Surface roughness

11 = Air Density

12 = Vertical velocity

13 = Wind Shear exponent

102

4

float

Height for this block (above ground level)

Default or N/A = -1

106

2

short

Direction for this block

-1 means not directional. Directions start at 0 = north and work clockwise

108

4

float

Wind Speed for this block

-1(default) means not by wind speed

112

8

Double

Probability for this block

Usually 1.0 (P<1.0 can be used to specify that this is one of multiple wind regimes each having its own probability)

120

4

Int32

ID for this group of blocks

Usually set to 0 – unused (can be used with P to specify multiple wind regimes within one file)

124

8

Int64

Offset of this block in this file

Start byte

132

1

byte

Data type

0 = float (default)

1 = double

2 = byte

3 = short

4 = long (32 bit) etc

133

2

Unsigned short

Unit (new)

0 = none (default)

1 = m

2 = m/s

3 = degree (+/-180)

4 = degree (0 - 360)

5 = %

135

29

byte

unused

 

100 + block index*64

2

Unsigned short

Data meaning for block index 1

 

….

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Constraints are:

All directional blocks contain same number of directions

All blocks have same horizontal resolution

All blocks share same horizontal grid points

All blocks share same number of directions (if directional)

If units are not appropriate for meaning, units are ignored

 

Block Structure

Each block is ordered in lines of X starting the bottom left hand corner. All values are stored as 4 byte floats by default.

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