get_contour

Context: contours

Synopsis

Retrieves the attribute value(s) of the contour.

Syntax

get_contour()
get_contour(id [,attribute])

Description

id - an optional ChipsId structure containing values to modify the currency state for the command or a string id to specify a contour within the current plot.
attribute - a string containing the name of the attribute to retrieve

The get_contour command returns a structure containing all the attribute values of the contour. To retrieve the value of a specific attribute, provide the attribute name and the id or ChipsId of the object.

Some values are set to "None" in the returned structure. These entries generally correspond to attributes which may only be modified at creation time, such as the object id.

Please see the section "Contour Preferences and Attributes" below the examples for a list of the contour attributes.

Data Range

The get_contour_range command returns the X and Y ranges of the current contour. The values are returned as [xmin, xmax, ymin, ymax]. There are also individual commands for retrieving just the x, y, or z range: get_contour_xrange, get_contour_yrange, and get_contour_zrange.

To see if a contour is hidden or visible, use the get_contour_visible command.

Advanced Functions

The module of advanced ChIPS functions contains other commands for retrieving attribute values (refer to "ahelp chips" for information on loading the module):

get_contour_algorithm
get_contour_color
get_contour_depth
get_contour_interval
get_contour_mode
get_contour_numlevels
get_contour_style
get_contour_thickness
get_contour_transform

Example 1

chips> add_contour("img.fits","color=red")
chips> print get_contour()
algorithm = 1
color = red
depth = 100
id = None
interval = 10.0
levels = [55.0, 60.0, 65.0, 70.0, 75.0, 80.0]
mode = nice
numlevels = 5
stem = None
style = solid
thickness = 1.0
wcs = None
chips> print get_contour().levels
[55.0, 60.0, 65.0, 70.0, 75.0, 80.0]
chips> print get_contour("ctr1", "color")
default

A contour is created and becomes current. Calling get_contour with no argument returns all the attributes of the object. The remaining calls show how get_contour can be used to access individual attributes of the contour.

Example 2

chips> add_contour("img.fits","color=red")
chips> add_contour([1,1,1,1,3,1,1,1,1], 3, 3)
chips> print get_contour("ctr1")

Two contours are created. get_contour is called with the id of the first contour, returning all attributes.

Example 3

chips> id = ChipsId()
chips> id.contour = "ctr1"
chips> print get_contour(id)

A ChipsId structure is created and the id.contour field is set to "ctr1". get_contour is called with the ChipsId.

Example 4

chips> ctratt = get_contour()
chips> print ctratt

Retrieve a structure containing the attribute values of the current contour and store the results in "ctratt". Print the contents of "ctratt".

Contour Preferences and Attributes

The attributes associated with contours are given in the following table, where the "Set?" column refers to whether the attribute can be changed using the set_contour() command. To change the contour preference settings prepend "contour." to the attribute name.

Attribute	Description	Options	Default	Set?
algorithm	the contouring algorithm to be used	standard, marching	marching	Yes
color	contour color	name or hex; see the Color section of "ahelp chipsopt"	default	Yes
depth	Depth used for the contour object	see the Depth section of "ahelp chipsopt"	default	Yes
interval	Indicates the delta value from one contour level to the next whem mode=interval	Non-negative value	10	Yes
levels	When setting, this attribute controls the the contour levels to display when the mode is "arbitrary". When using get_contour() this attribute contains the actual contour levels displayed.	Array or list of numbers	[]	Yes
mode	How the contour levels are determined	arbitrary\|count\|interval\|limits\|nice; see the Tick Mode section of "ahelp chipsopt"	nice	Yes
numlevels	number of contour levels when mode is count	Non-negative integer	5	Yes
stem	Stem used for contour id	An alpha-numeric character sequence that does not contain a space	ctr	No
style	Stipple pattern used to draw the line segment	see the Line Style section of "ahelp chipsopt"	solid	Yes
thickness	Thickness of the line	0.5 to 10.0; see the Thickness section of "ahelp chipsopt"	1	Yes
wcs	The name of the coordinate system to use	"logical", "physical", "world". You can also use the names of the transforms, such as "sky" and "EQPOS".	"world", if available.	No

Bugs

The list of contour levels may contain repeated values

The values returned in the levels attribute of get_contour() may contain repeated values; for instance in the example below the 60.0 value is repeated twice.

chips> get_contour().levels
[55.0, 60.0, 60.000000000000007, 65.0, 70.0, 75.0, 80.0]

See the bugs pages on the ChIPS website for an up-to-date listing of known bugs.