HeavyWeather History File Format
--------------------------------

Last Updated 2005/7/8
Compiled by Ben Udall

By default, weather history is stored in the history.dat file in the
HeavyWeather folder.  HeavyWeather and HeavyWeatherPro use two different
formats, both of which are presented below.  Initial format information
for HeavyWeatherPro was taken from Cyril Cavadore's program
(http://www.astrosurf.com/cavadore/meteo/stations_meteo/lacrosse/)


*******************

HeavyWeather V2.0 beta
La Crosse WS-2310 and WS-2315 weather stations

Each row of data is stored in 36 byte chunks starting from the beginning of
the file (no header).

Row
Offset  Type       Name              Unit
------  ---------  ----------------  -----
00      ULong [4]  unknown           - (Value is always 1)
04      ULong [4]  Timestamp         seconds from 1/1/1900 00:00:00 (GMT)
08      Float [4]  Abs Pressure      hectopascals (millibars)
12      Float [4]  Wind Speed        meters/second
16      ULong [4]  Wind Direction    see below
20      Float [4]  Total Rainfall    millimeters
24      Float [4]  Indoor Temp       Celsius
28      Float [4]  Outdoor Temp      Celsius
32      UWord [2]  Indoor Humidity   %
34      UWord [2]  Outdoor Humidity  %

At the end of the file is an additional 28 bytes providing information about
the dataset as a whole.

Offset  Type       Description
------  ---------  ----------------
00      ULong [4]  unknown 
04      Ulong [4]  unknown (0)
08      Float [4]  unknown (5.698)
12      ULong [4]  unknown (0)
16      ULong [4]  Number of rows
20      ULong [4]  Timestamp of the first row of data
24      ULong [4]  Timestamp of the last row of data


*******************

HeavyWeatherPro V1.1
La Crosse WS-3610 weather station

Each row of data is stored in 56 byte chunks starting from the beginning of
the file (no header).

ROW
OFFSET  Type        Name               Unit
------  ---------   ----------------   -----
00      Double [8]  Timestamp          days from 12/30/1899 00:00:00 (GMT)   
08      Float  [4]  Abs Pressure       hectopascals (millibars)
12      Float  [4]  Relative Pressure  hectopascals (millibars)
16      Float  [4]  Wind Speed         meters/second
20      ULong  [4]  Wind Direction     see below
24      Float  [4]  Wind Gust          meters/second
28      Float  [4]  Total Rainfall     millimeters
32      Float  [4]  New Rainfall       millimeters
36      Float  [4]  Indoor Temp        celsius
40      Float  [4]  Outdoor Temp       celsius
44      Float  [4]  Indoor Humidity    %
48      Float  [4]  Outdoor Humidity   %
52	ULong  [4]  unknown            - (Value is always 0)

Since the timestamp is a double, the fractional part represents fractions of
a day.  This is probably the same type as the Delphi TdateTime type.  More
information about this type can be found here:
http://www.aimtec.com.au/articles/ItsAboutTime/Default.htm


*******************

Wind Direction

Wind direction is encoded as an integer between 0 and 15.  To get the
wind direction in degrees, multiply the value by 22.5.  To get compass
directions (moving clockwise) 0 is North, 1 is North-Northeast, 2 is
Northeast, etc...
 0  N
 1  NNE
 2  NE
 3  ENE
 4  E
 5  ESE
 6  SE
 7  SSE
 8  S
 9  SSW
10  SW
11  WSW
12  W
13  WNW
14  NW
15  NNW