quiverm

Project 2-D quiver plot on axesm-based map

Syntax

quiverm(lat,lon,dlat,dlon)

quiverm(lat,lon,dlat,dlon,scale)

quiverm(lat,lon,dlat,dlon,LineSpec)

quiverm(lat,lon,dlat,dlon,LineSpec,"filled")

quiverm(lat,lon,dlat,dlon,LineSpec,scale,"filled")

h = quiverm(___)

Description

quiverm(lat,lon,dlat,dlon) creates a quiver plot on the current axesm-based map. The quiver plot has arrows with directional components dlat and dlon at the geographic coordinates specified by lat and lon. For example, the first arrow originates from the point lat(1) and lon(1), extends horizontally according to dlon(1), and extends vertically according to dlat(1). By default, the function scales the arrow lengths so that they do not overlap.

quiverm(lat,lon,dlat,dlon,scale) adjusts the lengths of the arrows:

• When scale is a positive number, the function automatically adjusts the lengths of arrows so they do not overlap, then stretches them by a factor of scale. For example, a scale of 2 doubles the length of arrows, and a scale of 0.5 halves the length of arrows.

• When scale is "off" or 0, such as quiverm(lat,lon,dlat,dlon,"off"), the function does not perform automatic scaling.

quiverm(lat,lon,dlat,dlon,LineSpec) specifies the line style, marker, and color. Markers appear at the points specified by lat and lon. If you specify a marker using LineSpec, the function does not display arrowheads.

quiverm(lat,lon,dlat,dlon,LineSpec,"filled") fills the markers specified by LineSpec.

quiverm(lat,lon,dlat,dlon,LineSpec,scale,"filled") adjusts the lengths of the arrows and fills the markers specified by LineSpec.

h = quiverm(___) returns the quiver plot, using any combination of input arguments from the previous syntaxes.

Examples

Project Quiver Plot on Map

Load sample data that represents air currents into the workspace, and select a subset of the data.

load("wind","x","y","u","v")
lat = y(11:22,11:22,1);
lon = x(11:22,11:22,1);
dlat = v(11:22,11:22,1);
dlon = u(11:22,11:22,1);

Create a map and display a quiver plot of the subset you selected. The matrices lat and lon represent the location of the base of each arrow, and dlat and dlon represent the directional components of each arrow. By default, the quiverm function shortens the arrows so they do not overlap.

figure
[latlim,lonlim] = geoquadline(lat,lon);
usamap(latlim,lonlim)

quiverm(lat,lon,dlat,dlon)

Input Arguments

lat — Latitude coordinates of bases of arrows

scalar | vector | matrix

Latitude coordinates of the bases of the arrows, specified as a scalar, a vector, or a matrix.

The sizes of lat, lon, dlat, and dlon must match.

Specify this argument using units that match the AngleUnits property of the axesm-based map.

Data Types: double

lon — Longitude coordinates of bases of arrows

scalar | vector | matrix

Longitude coordinates of the bases of the arrows, specified as a scalar, a vector, or a matrix.

The sizes of lat, lon, dlat, and dlon must match.

Specify this argument using units that match the AngleUnits property of the axesm-based map.

Data Types: double

dlat — Latitude components of arrows

scalar | vector | matrix

Latitude components of the arrows, specified as a scalar, vector, or matrix.

The sizes of lat, lon, dlat, and dlon must match.

Specify this argument using units that match the AngleUnits property of the axesm-based map.

Data Types: single | double

dlon — Longitude components of arrows

scalar | vector | matrix

Longitude components of the arrows, specified as a scalar, vector, or matrix.

The sizes of lat, lon, dlat, and dlon must match.

Specify this argument using units that match the AngleUnits property of the axesm-based map.

Data Types: single | double

LineSpec — Line style, marker, and color

character vector | string scalar

Line style, marker, and color, specified as a character vector or string scalar containing symbols. The symbols can appear in any order. You do not need to specify all three characteristics (line style, marker, and color).

If you specify a marker using LineSpec, then the quiverm function does not display arrowheads.

Example: "--or" is a red dashed line with circle markers

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line

Marker	Description	Resulting 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 Name	Short Name	RGB Triplet	Appearance
"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]

scale — Arrow scaling factor

nonnegative scalar | "off"

Arrow scaling factor, specified as a nonnegative scalar or "off". By default, the quiverm function automatically scales the arrows so they do not overlap. The quiverm function applies the specified scaling factor after it automatically scales the arrows.

To turn off automatic scaling, specify scale as "off" or 0. When you specify either of these values, the function plots the arrows from (lat, lon) to (lat+dlat, lon+dlon).

Output Arguments

h — Quiver plot

vector of Line objects

Quiver plot, returned as a vector of Line objects.

Version History

Introduced before R2006a