Reports the co-ordinates of positions selected using the cursor
Positions may be reported in several different co-ordinate Frames (see Parameter FRAME). Optionally, the corresponding pixel co-ordinates at each position may also be reported (see Parameter SHOWPIXEL).
The picture or pictures within which positions are required can be selected in several ways (see Parameters MODE and NAME).
Restrictions can be made on the number of positions to be given (see Parameters MAXPOS and MINPOS), and screen output can be suppressed (see the “Notes”).
A domain name such as SKY, AXIS, PIXEL.
An integer value giving the index of the required Frame.
An IRAS90 Sky Co-ordinate System (SCS) values such as "EQUAT(J2000)"
(see SUN/163).
If a null (!
) value is supplied, the positions will be stored in the current Frame. [!]
"1996.8"
for example).
Such values are interpreted as a Besselian epoch if less than 1984.0 and as a
Julian epoch otherwise. "Chain"
or "Poly"
. If TRUE
, polygons will be
closed by joining the first position to the last position. [
current value]
COMP = LITERAL (Read)
"Data"
, "Quality"
,
"Variance"
, or "Error"
(where "Error"
is an alternative to "Variance"
and causes the
square root of the variance values to be displayed). If "Quality"
is specified, then
the quality values are treated as numerical values (in the range 0 to 255). ["Data"]
TRUE
, a detailed description of the co-ordinate Frame
in which subsequent positions will be reported is produced each time a position is
reported within a new picture. [
current value]
[
current
graphics device]
"1996.8"
for example). Such values are
interpreted as a Besselian epoch if less than 1984.0 and as a Julian epoch
otherwise. A domain name such as SKY, AXIS, PIXEL. The special domains AGI_WORLD and AGI_DATA are used to refer to the world and data co-ordinate system stored in the AGI graphics database. They can be useful if no WCS information was store with the picture when it was created.
An integer value giving the index of the required Frame.
An IRAS90 Sky Co-ordinate System (SCS) values such as "EQUAT(J2000)"
(see SUN/163).
If a null value (!
) is supplied, positions are reported in the co-ordinate Frame which
was current when the picture was created. [!]
"Chain"
or "Poly"
. It specifies
whether the curves drawn between positions should be straight lines, or should be
geodesic curves. In many co-ordinate Frames geodesic curves will be simple straight
lines. However, in others (such as the majority of celestial co-ordinates Frames)
geodesic curves will be more complex curves tracing the shortest path between
two positions in a non-linear projection. [FALSE]
TRUE
, then messages are displayed describing the use of the mouse prior
to obtaining the first position. Note, these informational messages are not
suppressed by setting MSG_FILTER environment variable to QUIET
. [TRUE]
"Text"
. The supplied string should contain two
characters; the first should be "B"
, "C"
or "T"
, meaning bottom, centre or top.
The second should be "L"
, "C"
or "R"
, meaning left, centre or right. The text
is displayed so that the supplied position is at the specified point within
the displayed text string. ["CC"]
!
) means that no file is
created. [!]
"Chain"
or "Mark"
. It specifies the symbol with which
each position should be marked, and should be given as an integer PGPLOT marker
type. For instance, 0
gives a box, 1
gives a dot, 2
gives a cross, 3
gives
an asterisk, 7
gives a triangle. The value must be larger than or equal to
−31.
[
current value]
[200]
[0]
"Current"
–- reports positions within the current picture in the AGI database. If a
position does not lie within the current picture, an extrapolated position is reported,
if possible.
"Dynamic"
–- reports positions within the top-most picture under the cursor in the AGI
database. Thus the second and subsequent cursor hits may result in the selection of a
new picture.
"Anchor"
–- lets the first cursor hit select the picture in which all positions are to
be reported. If a subsequent cursor hit falls outside this picture, an extrapolated
position is reported if possible.
["Dynamic"]
"DATA"
. A null (!
) or blank string means
that pictures of all names may be selected. NAME is ignored when MODE="Current"
. [!]
.fit
is given, then the
catalogue is stored as a FITS binary table. If a file type of .txt
is given, then
the catalogue is stored in a text file in "Small Text List"
(STL) format. If
no file type is given, then .fit
is assumed. If a null value is supplied, no
output positions list is produced. See also Parameter CATFRAME. [!]
"None"
–- No graphics are produced.
"Mark"
–- Each position is marked by the symbol specified by Parameter MARKER.
"Poly"
–- Causes each position to be joined by a line to the previous position. These
lines may be simple straight lines or geodesic curves (see Parameter GEODESIC). The
polygons may optionally be closed by joining the last position to the first (see
Parameter CLOSE).
"Chain"
–- This is a combination of "Mark"
and "Poly"
. Each position is marked by a
symbol and joined by a line to the previous position. Parameters MARKER, GEODESIC and
CLOSE are used to specify the symbols and lines to use.
"Box"
–- A rectangular box with edges parallel to the edges of the graphics device is
drawn with the specified position at one corner, and the previously specified position
at the diagonally opposite corner.
"Vline"
–- A vertial line is drawn through each specified position, extending the
entire height of the selected picture.
"Hline"
–- A horizontal line is drawn through each specified position, extending the
entire width of the selected picture.
"Cross"
–- A combination of "Vline"
and "Hline"
.
"Text"
–- A text string is used to mark each position. The string is drawn horizontally
with the justification specified by Parameter JUST. The strings to use for each
position are specified using Parameter STRINGS.
[
current value]
TRUE
, the pixel value within the
displayed NDF is reported for each selected position. This is only possible if the
picture within which position are being selected contains a reference to an existing
NDF. The NDF array component to be displayed is selected via Parameter COMP. [FALSE]
TRUE
, the pixel co-ordinates of each selected position
are shown on a separate line, following the co-ordinates requested using Parameter
FRAME. If pixel co-ordinates are being displayed anyway (see Parameter FRAME) then a
value of FALSE
is used for. SHOWPIXEL. [
current value]
"TEXT"
. The first string in the group is used to mark
the first position, the second string is used to mark the second position,
etc. If more positions are given than there are strings in the group, then
the extra positions will be marked with an integer value indicating the index
within the list of supplied positions. If a null value (!
) is given for the
parameter, then all positions will be marked with integer indices, starting at
1.
A comma-separated list should be given in which each element is either a
marker string, or the name of a text file preceded by an up-arrow character
"
.
Such text files should contain further comma-separated lists which will be read and
interpreted in the same manner. Note, strings within text files can be separated by new
lines as well as commas.
"
A comma-separated list of strings should be given in which each string is either an
attribute setting, or the name of a text file preceded by an up-arrow character
"
.
Such text files should contain further comma-separated lists which will be read and
interpreted in the same manner. Attribute settings are applied in the order in which
they occur within the list, with later settings overriding any earlier settings given
for the same attribute.
"
Each individual attribute setting should be of the form:
<name>=<value>
where <name>
is the name of a plotting attribute, and
<value>
is the value to assign to the attribute. Default values will be used for any
unspecified attributes. All attributes will be defaulted if a null value (!
)–-the
initial default–-is supplied. To apply changes of style to only the current invocation,
begin these attributes with a plus sign. A mixture of persistent and temporary style
changes is achieved by listing all the persistent attributes followed by a plus sign
then the list of temporary attributes.
See Section E for a description of the available attributes. Any unrecognised attributes are ignored (no error is reported).
In addition to the attributes which control the appearance of the graphics (Colour,
Font, etc.), the following attributes may be set in order to control the appearance of
the formatted axis values reported on the screen: Format, Digits, Symbol, Unit. These may
be suffixed with an axis number (e.g. "Digits(2)"
) to refer to the values displayed for
a specific axis. [
current value]
a.FIT
, together with any
associated WCS information. slice.FIT
. The catalogue may be used to communicate the
positions to later applications (LISTSHOW, PROFILE, etc.). ^
mystyle,digits(1)=5,digits(2)=7"
The unformatted values stored in the output Parameter LASTPOS, may not be in the same units as the formatted values shown on the screen and logged to the log file. For instance, unformatted celestial co-ordinate values are stored in radians.
The current picture is unchanged by this application.
In DYNAMIC and ANCHOR modes, if the cursor is situated at a position where there are no pictures of the selected name, the co-ordinates in the BASE picture are reported.
Pixel co-ordinates are formatted with 1 decimal place unless a format has already been specified by setting the Format attributes for the axes of the PIXEL co-ordinate Frame (e.g. using application WCSATTRIB).
Positions can be removed (the instructions state how), starting from the most-recent one. Such positions are excluded from the output positions list and log file (if applicable). If graphics are being used to mark the positions, then removed positions will be highlighted by drawing a marker of type 8 (a circle containing a cross) over the removed positions in a different colour.
The positions are not displayed on the screen when the message filter environment
variable MSG_FILTER is set to QUIET
. The creation of output parameters and files is
unaffected by MSG_FILTER. The display of informational messages describing the use of
the cursor is controlled by the Parameter INFO.