scircleg

Add small circle to `axesm`-based map using mouse

Syntax

```h = scircleg(ncirc) h = scircleg(ncirc,npts) h = scircleg(ncirc,LineSpec) h = scircleg(ncirc,PropertyName,PropertyValue,...) [lat,lon] = scircleg(ncirc,npts,...) h = scircleg(track,ncirc,...) ```

Description

`h = scircleg(ncirc)` brings forward the current `axesm`-based map and waits for the user to make (2 * `ncirc`) mouse clicks. The output `h` is a vector of handles for the `ncirc` small circles, which are then displayed.

`h = scircleg(ncirc,npts)` specifies the number of plotting points to be used for each small circle. `npts` is 100 by default.

`h = scircleg(ncirc,LineSpec)` specifies the line style, marker, and color.

`h = scircleg(ncirc,PropertyName,PropertyValue,...)` allows property name/property value pairs to be set, where `PropertyName` and `PropertyValue` are recognized by the `line` function.

`[lat,lon] = scircleg(ncirc,npts,...)` returns the coordinates of the plotted points rather than the handles of the small circles. Successive circles are stored in separate columns of `lat` and `lon`.

`h = scircleg(track,ncirc,...)` specifies the logic with which ranges are calculated. If track is `'gc'` (the default), great circle distance is used. If track is `'rh'`, rhumb line distance is used.

This function is used to define small circles for display using mouse clicks. For each circle, two clicks are required: one to mark the center of the circle and one to mark any point on the circle itself, thereby defining the radius.

Background

A small circle is the locus of all points an equal surface distance from a given center. For true small circles, this distance is always calculated in a great circle sense; however, the `scircleg` function allows a locus to be calculated using distances in a rhumb line sense as well. You can modify the circle after creation by shift+clicking it. The circle is then in edit mode, during which you can change the size and position by dragging control points, or by entering values into a control panel. Shift+clicking again exits edit mode.

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Line Style, Marker, and Color

Specify the line style, marker, and color as a character vector or string containing symbols. The symbols can appear in any order. You do not need to specify all three characteristics (line style, marker, and color). For example, specify a red dashed line using `'--r'`.

Line StyleDescriptionResulting Line
`"-"`Solid line

`"--"`Dashed line

`":"`Dotted line

`"-."`Dash-dotted line

MarkerDescriptionResulting Marker
`"o"`Circle

`"+"`Plus sign

`"*"`Asterisk

`"."`Point

`"x"`Cross

`"_"`Horizontal line

`"|"`Vertical line

`"square"`Square

`"diamond"`Diamond

`"^"`Upward-pointing triangle

`"v"`Downward-pointing triangle

`">"`Right-pointing triangle

`"<"`Left-pointing triangle

`"pentagram"`Pentagram

`"hexagram"`Hexagram

Color NameShort NameRGB TripletAppearance
`"red"``"r"``[1 0 0]`

`"green"``"g"``[0 1 0]`

`"blue"``"b"``[0 0 1]`

`"cyan"` `"c"``[0 1 1]`

`"magenta"``"m"``[1 0 1]`

`"yellow"``"y"``[1 1 0]`

`"black"``"k"``[0 0 0]`

`"white"``"w"``[1 1 1]`

Version History

Introduced before R2006a