Sponsored Content
The Lounge What is on Your Mind? Happy New Year 2020 to all :) Post 303042616 by RavinderSingh13 on Wednesday 1st of January 2020 10:21:43 AM
Old 01-01-2020
Happy New Year 2020 to all :)

Hello All,

I would like to wish A very Happy New Year 2020 to all. May GOD bless all of us with TRUE knowledge, wisdom, great attitude, honesty, hard working capability, great health Smilie

Cheers and let us all have fun/learning/sharing/caring on this GREAT forum UNIX.com, love you UNIX.com always SmilieSmilie

Thanks,
R. Singh
These 6 Users Gave Thanks to RavinderSingh13 For This Post:
 

2 More Discussions You Might Find Interesting

1. News, Links, Events and Announcements

Happy Holidays and New Year!

To All UNIX Forum Members! Neo has sent you a flash greeting card. You may see it by clicking on the link below: http://www.afreegreetingcard.com/cgi-bin/magiccard.cgi?122920242420332 :) (5 Replies)
Discussion started by: Neo
5 Replies

2. What is on Your Mind?

Welcome 2016, Happy New Year to All

Hello All, I wanted to wish Happy New Year 2016 to every one in this forum. May GOD gives us strength to do hard work, learn new things, enjoy each and every moment of our life, do new adventurous. Take care and enjoy. Here is a famous quote: Thanks, R. Singh "GOD helps those Who help... (1 Reply)
Discussion started by: RavinderSingh13
1 Replies
FITCIRCLE(l)															      FITCIRCLE(l)

NAME
fitcircle - find mean position and pole of best-fit great [or small] circle to points on a sphere. SYNOPSIS
fitcircle [ xyfile ] -Lnorm [ -H[nrec] ] [ -S ] [ -V ] [ -: ] [ -bi[s][n] ] DESCRIPTION
fitcircle reads lon,lat [or lat,lon] values from the first two columns on standard input [or xyfile]. These are converted to cartesian three-vectors on the unit sphere. Then two locations are found: the mean of the input positions, and the pole to the great circle which best fits the input positions. The user may choose one or both of two possible solutions to this problem. The first is called -L1 and the second is called -L2. When the data are closely grouped along a great circle both solutions are similar. If the data have large dispersion, the pole to the great circle will be less well determined than the mean. Compare both solutions as a qualitative check. The -L1 solution is so called because it approximates the minimization of the sum of absolute values of cosines of angular distances. This solution finds the mean position as the Fisher average of the data, and the pole position as the Fisher average of the cross-products between the mean and the data. Averaging cross-products gives weight to points in proportion to their distance from the mean, analogous to the "leverage" of distant points in linear regression in the plane. The -L2 solution is so called because it approximates the minimization of the sum of squares of cosines of angular distances. It creates a 3 by 3 matrix of sums of squares of components of the data vectors. The eigenvectors of this matrix give the mean and pole locations. This method may be more subject to roundoff errors when there are thousands of data. The pole is given by the eigenvector corresponding to the smallest eigenvalue; it is the least-well represented factor in the data and is not easily estimated by either method. -L Specify the desired norm as 1 or 2, or use -L or -L3 to see both solutions. OPTIONS
xyfile ASCII [or binary, see -b] file containing lon,lat [lat,lon] values in the first 2 columns. If no file is specified, fitcircle will read from standard input. -H Input file(s) has Header record(s). Number of header records can be changed by editing your .gmtdefaults file. If used, GMT default is 1 header record. -S Attempt to fit a small circle instead of a great circle. The pole will be constrained to lie on the great circle connecting the pole of the best-fit great circle and the mean location of the data. -V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"]. -: Toggles between (longitude,latitude) and (latitude,longitude) input/output. [Default is (longitude,latitude)]. Applies to geo- graphic coordinates only. -bi Selects binary input. Append s for single precision [Default is double]. Append n for the number of columns in the binary file(s). [Default is 2 input columns]. EXAMPLES
Suppose you have lon,lat,grav data along a twisty ship track in the file ship.xyg. You want to project this data onto a great circle and resample it in distance, in order to filter it or check its spectrum. Try: fitcircle ship.xyg -L2 project ship.xyg -Cox/oy -Tpx/py -S -pz | sample1d -S-100 -I1 > output.pg Here, ox/oy is the lon/lat of the mean from fitcircle, and px/py is the lon/lat of the pole. The file output.pg has distance, gravity data sampled every 1 km along the great circle which best fits ship.xyg SEE ALSO
gmt(1gmt), project(1gmt), sample1d(1gmt) 1 Jan 2004 FITCIRCLE(l)
All times are GMT -4. The time now is 10:37 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy