.TH HOTSPOTTER 1gmt "15 Jul 2011" "GMT 4.5.7" "Generic Mapping Tools"
.SH NAME
hotspotter \- Create CVA image from seamount flowlines 
.SH SYNOPSIS
\fBhotspotter\fP [\fIinfile(s)\fP] \fB\-E\fP\fIstage_file\fP 
\fB\-G\fP\fICVAgrid\fP \fB\-I\fP\fIxinc\fP[\fIunit\fP][\fB=\fP|\fB+\fP][/\fIyinc\fP[\fIunit\fP][\fB=\fP|\fB+\fP]] 
\fB\-R\fP\fIwest\fP/\fIeast\fP/\fIsouth\fP/\fInorth\fP[\fBr\fP] [ \fB\-C\fP ] [ \fB\-D\fP\fIfactor\fP ] [ \fB\-F\fP ] 
[ \fB\-H\fP[\fBi\fP][\fInrec\fP] ] [ \fB\-N\fP\fIupper_age\fP ] [ \fB\-S\fP ] 
[ \fB\-T\fP ] [ \fB\-V\fP ] [ \fB\-:\fP[\fBi\fP|\fBo\fP] ] [ \fB\-bi\fP[\fBs\fP|\fBS\fP|\fBd\fP|\fBD\fP[\fIncol\fP]|\fBc\fP[\fIvar1\fP\fB/\fP\fI...\fP]] ]
.SH DESCRIPTION
\fBhotspotter\fP reads (longitude, latitude, amplitude, radius, age) records
from \fIinfiles\fP  [or standard input] and calculates flowlines using the 
specified stage pole (Euler) rotations.  These flowlines are convolved with
the shape of the seamount (using a Gaussian shape given amplitude and radius
= 6 sigma) and added up to give a Cumulative Volcano Amplitude grid (CVA).
See option \fB\-:\fP on how to read (latitude,longitude,...) files.
.br
	No space between the option flag and the associated arguments.  Use upper case for the
option flags and lower case for modifiers.
.TP
\fIinfile(s)\fP
Data file(s) to be processed.  If not given, standard input is read.
.TP
\fB\-E\fP
Give file with rotation parameters.  This file must contain
one record for each rotation; each record must be of the following format:
.br
.sp
	\fIlon lat tstart [tstop] angle\fP [ \fIkhat a b c d e f g df\fP ]
.br
.sp
where \fItstart\fP and \fItstop\fP are in Myr and \fIlon lat angle\fP are in degrees.
\fItstart\fP and \fItstop\fP are the ages of the old and young ends of a stage.  If \fB\-C\fP is set then a total
reconstruction rotation is expected and \fItstop\fP is implicitly set to 0 and
should not be specified in the file.  If a covariance matrix \fBC\fP for the rotation is available
it must be specified in a format using the nine optional terms listed in brackets.
Here, \fBC\fP = (\fIg\fP/\fIkhat\fP)*[ \fIa b d; b c e; d e f\fP ] which shows \fBC\fP
made up of three row vectors.
If the degrees of freedom (\fIdf\fP) in fitting the rotation is 0 or not given it is set to 10000.
Blank lines and records whose first column contains # will be ignored.
.TP
\fB\-G\fP
Specify name for output grid file.
.TP
\fB\-I\fP
\fIx_inc\fP [and optionally \fIy_inc\fP] is the grid spacing. Optionally, append a suffix
modifier.  \fBGeographical (degrees) coordinates\fP: Append \fBm\fP to
indicate arc minutes or \fBc\fP to indicate arc seconds.  If one of the units \fBe\fP, \fBk\fP, \fBi\fP,
or \fBn\fP is appended instead, the increment is assumed to be given in meter, km, miles, or
nautical miles, respectively, and will be converted to the equivalent degrees longitude at
the middle latitude of the region (the conversion depends on \fBELLIPSOID\fP).  If /\fIy_inc\fP is given but set to 0 it will be reset equal to
\fIx_inc\fP; otherwise it will be converted to degrees latitude.  
\fBAll coordinates\fP: If \fB=\fP is appended then
the corresponding max \fIx\fP (\fIeast\fP) or \fIy\fP (\fInorth\fP) may be slightly adjusted to fit exactly the given increment
[by default the increment may be adjusted slightly to fit the given domain].  Finally, instead
of giving an increment you may specify the \fInumber of nodes\fP desired by appending \fB+\fP to
the supplied integer argument; the increment is then recalculated from the number of nodes and the domain.
The resulting increment value depends on whether you have selected a gridline-registered
or pixel-registered grid; see Appendix B for details.  Note: if \fB\-R\fP\fIgrdfile\fP is used then
grid spacing has already been initialized; use \fB\-I\fP to override the values.
.TP
\fB\-R\fP
\fIwest, east, south,\fP and \fInorth\fP specify the Region of interest, and you may specify them
in decimal degrees or in [+-]dd:mm[:ss.xxx][W|E|S|N] format.  Append \fBr\fP if lower left and upper right
map coordinates are given instead of w/e/s/n.  The two shorthands \fB\-Rg\fP and \fB\-Rd\fP stand for global domain
(0/360 and -180/+180 in longitude respectively, with -90/+90 in latitude). Alternatively, specify the name
of an existing grid file and the \fB\-R\fP settings (and grid spacing, if applicable) are copied from the grid.
.SH OPTIONS
.TP
\fB\-C\fP
Expect Total Reconstruction Rotations rather than Forward Stage Rotations [Default].
File format is similar to the stage pole format except that the \fItstart\fP column
is not present (assumed to be 0 Ma).
.TP
\fB\-D\fP
Modify the sampling interval along flowlines.  Default [0.5] gives approximately 2 points within
each grid box.  Smaller factors gives higher resolutions at the expense of longer processing time.
.TP
\fB\-F\fP
Force pixel registration [Default is grid registration].
.TP
\fB\-H\fP
Input file(s) has header record(s).  If used, the default number of header records is \fBN_HEADER_RECS\fP.
Use \fB\-Hi\fP if only input data should have header records [Default will write out header records if the
input data have them]. Blank lines and lines starting with # are always skipped.
.TP
\fB\-N\fP
Set the upper age to assign seamounts whose crustal age is unknown (i.e. NaN) [no upper age].
.TP
\fB\-S\fP
Normalize the resulting CVA grid to percentages of the CVA maximum.
.TP
\fB\-T\fP
Truncate seamount ages exceeding the upper age set with \fB\-N\fP [no truncation].
.TP
\fB\-V\fP
Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
.TP
\fB\-:\fP
Toggles between (longitude,latitude) and (latitude,longitude) input and/or output.  [Default is (longitude,latitude)].
Append \fBi\fP to select input only or \fBo\fP to select output only.  [Default affects both].
.TP
\fB\-bi\fP
Selects binary input.
Append \fBs\fP for single precision [Default is \fBd\fP (double)].
Uppercase \fBS\fP or \fBD\fP will force byte-swapping.
Optionally, append \fIncol\fP, the number of columns in your binary input file
if it exceeds the columns needed by the program.
Or append \fBc\fP if the input file is netCDF. Optionally, append \fIvar1\fP\fB/\fP\fIvar2\fP\fB/\fP\fI...\fP to
specify the variables to be read.
[Default is 5 input columns].
.SH EXAMPLES
To create a CVA image from the Pacific (x,y,z,r,t) data in the file seamounts.d,
using the DC85.d Euler poles, run
.br
.sp
\fBhotspotter\fP seamounts.d \fB\-E\fPDC85.d \fB\-G\fPCVA.grd \fB\-R\fP130/260/-66/60 \fB\-I\fP10\fBm\fP \fB\-N\fP145 \fB\-T\fP \fB\-V\fP
.br
.sp
This file can then be plotted with \fBgrdimage\fP.
.SH COORDINATES
Data coordinates are assumed to be geodetic and will automatically be converted to geocentric
before spherical rotations are performed.  We convert back to geodetic coordinates for output.
Note: If your data already are geocentric, you can avoid the conversion by using --ELLIPSOID=sphere.
.SH "SEE ALSO"
.IR GMT (1),
.IR grdimage (1),
.IR grdrotater (1),
.IR grdspotter (1),
.IR project (1),
.IR mapproject (1),
.IR backtracker (1),
.IR originator (1)
.SH REFERENCES
Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80 (29), p. 319.
.br