Create README.md

README.md

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+#	About Grav-TC Version 1.2
+
+This is a program to generate correction table for measured gravity data.
+Value calculated is the UPWARD pull due to the sun and moon.
+To use as correction to measured gravity data, you would need to ADD these numbers, not subtract them.
+
+The algorithm used is that of Longman, I.M., Formulas for Computing the Tidal Acceleration Due to the Moon and the Sun., J. Geoph. Res., 1959
+
+Math calculation are ported from TIDES program by J. L. Ahern which was written in QBASIC.
+
+Copyright © 2014-2017 Adien Akhmad
+Department of Geophysics, Universitas Gadjah Mada
+
+#	How to use
+
+There are two modes you can use this program.
+
+1. Compute variations in g due to the moon and sun as a function of time on a given location on earth. (Normal mode)
+2. Compute g due to the moon and sun as a function of location and time. (Read from file mode)
+
+#	Normal Mode
+
+You can find all the controls in the main windows.
+	These are the paramaters you must set:
+	1. Position
+		X-Position	: Longitude or Easting (to switch between geographic and projected system click [Coordinate Sytem] menu and select from there)
+		Y-Position	: Latitude or Northing (to switch between geographic and projected system click [Coordinate Sytem] menu and select from there)
+		Elevation	: in meters
+	2. Time
+		Time Zone	: the time zone of the begin time and end time.
+		Begin Time	: the program will start the calculation at this specified hour, day, month and year. Value must be earlier than End Time.
+		End Time	: the program will stop the calculation at this specified hour, day, month and year. Value must be later than Begin Time.
+		Interval	: the time interval the program will be using, value are in minutes.
+
+	These are displayed after calculation:
+	1. Table
+		Date Time	: value of the time used in calculation.
+		g Moon		: calculated variation of g due to the moon
+		g Sun		: calculated variation of g due to the sun
+		g Total		: combined variation of g due to the moon and sun (g0)
+	2. Chart		: display a line chart representing variations of g0 versus time.
+
+#	Read From File Mode
+
+You can find the controls by clicking [File] and [Read From File]. A pop up window will appear.
+
+	1. Click on [Open] to select your file.
+	2. Set the time zone to match the time zone of the time in your text file.
+	3. Change coordinate system to match the coordinates in your text file.
+	4. If UTM coordinate system is selected, a combo box control will be active, click on the arrow and select the UTM zone of the coordinates in your text file.
+	5. Click [Generate]
+	6. A new column containing the calculated g will appear.
+	7. Click [Copy] if you wish to copy the generated table to clipboard.
+	8. Click [Save As] if you wish to save the generated table to a text file.
+
+#	File Input Format (a sample file is provided)
+
+	The file extension can be in any format (as long as it is a text file).
+	Any line beginning with '#' are treated as comment and will be ignored.
+
+	The input text format must be on the following structure (must be tab delimited) :
+
+		datetime    x-position    y-position    elevation
+
+	Supported datetime format :
+		d-M-yy H:mm 		16-3-15 14:00
+		d-M-yyyy H:mm 		16-3-2015 14:00
+		d-M-yyyy H:mm:ss	16-3-2015 14:00:00
+		
+	X-Position and Y-Position can be in either geographic decimal degree or UTM, elevation are in meters.
+
+		110.1116	-7.89996	100
+		or
+		402071.53	9126653.36	100
+
+	Above combined we have the complete format
+
+		# grav-tc file input format geographic coordinate example
+		16-03-2015 14:00    110.1116    -7.89996    100
+		16-03-2015 14:03    110.1234    -7.89996    130
+		16-03-2015 14:07    110.1356    -7.89996    98
+
+		or
+
+		# grav-tc file input format UTM coordinate example
+		17-03-2015 14:00    402071.53    9126653.36    100
+		17-03-2015 14:03    403071.53    9126653.36    130
+		17-03-2015 14:07    404071.53    9126653.36    98
+		
+#	Credits
+
+		J. L. Ahern, the original author of TIDES.
+		Tom Van Baak, for conversion of TIDES from QBASIC to C.
+		Yusuke Kamiyamane, for the awesome icons.
+		ZedGraph library, for the line chart.
+		ProjNet library, for the conversion of coordinates system.
+		FileHelpers library, for file handling.
+		
+==================================================================
+#	Change Log
+==================================================================
+# v1.0b
+	- First Beta Release
+# v1.0b2
+	- Bug Fixed	: Incorrectly convert deg min sec to decimal
+	- Changed	: Coordinate now only accept positive number.
+	- Added		: Option to choose N/S and E/W
+# v1.0
+	- New		: Tab Control and Chart
+	- Fixed		: Application now show wait cursor on loading.
+# v1.1.0 (15 March 2015)
+	- Code restructure.
+	- GUI Improvement
+	- New		: added support for coordinate input in Projected Coordinate System (WGS84 UTM)
+	- New		: Coordinate System menu to switch between different coordinate system and format.
+	- New		: read from file mode
+	- Changed	: Edit menu is removed. Replaced by Coordinate System menu.
+# v1.1.3 (21 March 2015)
+	- Fixed		: Wrong latitude and longitude limit on Deg Min Sec mode after switching from other input mode.
+	- Changed	: When latitude value are 90, minute and seconds value will automatically reset to zero.
+				  When longitude value are 180, minute and seconds value will automatically reset to zero.
+# v1.2 (02 September 2017)
+	- Internal code refactor
+	- Fixed		: Hour angle of the sun is not computed westward. This caused as if the latitude sign is reversed in calculation.
+	- Fixed		: Wrong unit label on y-axis
+				
+