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HMI Ring Diagrams
Pipeline Module Specifications
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maproj
Module Version
1.2 20 VI 2016
General Description
maproj takes as its input a dataset of records representing solar
image data, and produces as its output a corresponding set of records
representing the data mapped at selected heliographic coordinates.
The mapping algorithms and parameters are the same as those used in
mtrack.
Status
This version has been superseded by Version 1.3
Included in JSOC release 8.12
Not used in ring-diagram pipelines
The source code and Makefile are in the JSOC CVS repository
This version supersedes Version 1.1
Usage
maproj [-cnorvxGM] in= InputDescriptor out= OutputDescriptor
[param= val ...]
Flags
-c center the output map(s) at the coordinates of the input
image center(s)
-n no output, diagnistics only; for testing
-s interpret clon as Stonyhurst for image observation time
rather than Carrington
-v run verbose
-M correct for MDI distortion
-R convert scalars assuming line-of-sight components of radial vectors
Parameters
in the name of an input data set (record selection).
No default, must be provided.
out the name of the output data series, which must already
exist; record selection is based on runtime parameters
and the series prime keywords. No default, must be provided.
clat the heliographic latitude (in degrees) of the center
of the mapped image(s). If not specified, map will be centered at
latitude of image center of first image in input data set.
Default: Not Specified
clon the Carrrington (or Stonyhurst) latitude (in degrees)
of the mapped image(s). If not specified, map will be centered at
the Carrington longitude of image center, i.e. at
Stonyhurst longitude 0, of first image in input data set.
Default: Not Specified
scale the scale of the mapped region(s) at map center, in
heliographic degrees per pixel. Invalid default, must be
specified
map the mapping projection option; recognized values are:
carree, Cassini, Mercator, cyleqa, sineqa, gnomonic,
Postel, stereographic, orthographic, and Lambert.
Default: orthographic.
interp an option for spatial interpolation in the input images;
recognized values are cubiconv, nearest (for nearest
neighbor “interpolation”), and bilinear Default: cubiconv
grid if specified, the spacing, in deg, of a grid of latitude
and longitude lines that will be superimposed on the mapped
image(s) by setting the values of nearby pixels to NaN.
Default: unspecified
cols number of columns in the output map(s) (pixels). Default: 0,
but at least one of cols and rows must be set non-zero; if
either is 0, it will be set to the value of the other, so
that the map(s) will be square.
rows number of rows in the output maps (pixels). Default: 0;
see cols.
map_pa the position angle of heliographic north on the output
maps, measured westward (counter-clockwise), in deg.
Default: 0.
bscale the scaling to be applied to output data stored externally as
short integers to convert to floating-point values. An invalid
value, such as the default, implies output scaling according to
the segment default for the output series. Default: 0.0.
bzero the offset to be applied to output data stored externally as
short integers, after multiplication by bscale, to convert to
floating-point values. An invalid value, such as the default,
implies output offsets according to the segment default for the
output series. Default: unspecified
clon_key the key name to be used for the key value representing the
observer Carrington longitude at the time of observation in
the input data series; Default: CRLN_OBS
clat_key the key name to be used for the key value representing the
observer heliographic latitude at the time of observation in
the input data series; Default: CRLT_OBS
rsun_key the key name to be used for the key value representing the
solar image semi-diameter (in pixels) at the time of
observation in the input data series; Default: R_SUN
apsd_key the key name to be used for the key value representing the
apparent solar semi-diameter (in arcsec) at the time of
observation in the input data series; Default: RSUN_OBS
dsun_key the key name to be used for the key value representing the
distance between the sun and the observer (in m) at the time of
observation in the input data series; Default: DSUN_OBS
Request_ID RequestID for jsoc export management; Default: none
Input Data series class:
solar image data
Sample input series:
hmi.V_45s
mdi.fd_V
Input keys used or inspected:
clon_key*, crot_key*, clat_key*, rsun_key*, apsd_key*, dsun_key*,
CUNIT1, CUNIT2, CDELT1, CDELT2, CRPIX1, CRPIX2, R_SUN, OBS_ASD,
CROTA2, S_MAJOR, S_MINOR, S_ANGLE
* specified as module argument
Output Data series class:
mapped image data
Output keys set (if possible):
WCSNAME, WCSAXES, CTYPE1, CTYPE2, CUNIT1, CUNIT2, CRPIX1, CRPIX2,
CRVAL1, CRVAL2, CDELT1, CDELT2, PC1_1, PC1_2, PC2_1, PC2_2,
LonHG, LatHG, MapProj, MapScale, Width, Height, Size, Map_PA, RSunRef,
Interp, Module, BLD_VERS, Created, Source, Input
Sample output series:
su_rsb.genmap
Changes from Previous Version
Trap failed segment reads
Added nomap option -n for testing
Bugs in current version
If not included as part of the input dataset specification, the data segment
mapped will be the 2-dimensional segment with the lowest segment number.
If there are multiple data segments of rank 2 in the output series, a
warning is generated.
There is no provision for detrending prior to mapping.
Image geometry for cases with unequal scales CDELTi is not to be trusted
The image foreshortening corrections are appropriate for 1 AU, independent
of DSUN_OBS.
The input of the ellipse position angle has not been verified, but then
neither has the correction for ellipticity of the image altogether.
The input data are unconditionally read in as floats (single-precision).
There is evidently no WCS conventional name for the Cassini-Soldner
(transverse plate carree) projection; CAS is arbitrarily used; the
alternative would be to interchange HGLT and HGLN, but that would
necessitate a change in the position angle.
Only mapping from image (plate) coordinates is supported; there is no
provision for remapping between different projections.