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 |
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…. |
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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.