Skip to content

Latest commit

 

History

History
82 lines (57 loc) · 3.09 KB

itslive_quiver_documentation.md

File metadata and controls

82 lines (57 loc) · 3.09 KB

← Back to ITS_LIVE main page

itslive_quiver documentation

The itslive_quiver plots ITS_LIVE velocity data as quiver arrows.

Tip: Zoom to desired map extents BEFORE calling itslive_quiver.

Syntax

itslive_quiver(region)
itslive_quiver(region,'colorspec')
itslive_quiver(...Name,Value) 
itslive_quiver(...,'density','DensityFactor') 
h = itslive_quiver(...)

Description

itslive_quiver(region) plots a quiver plot on the current map. The region is a number between 1 and 19. For a map of regions, type itslive_regions.

itslive_quiver('colorspec') specifies a color of the vectors, like 'r' for red.

itslive_quiver(...Name,Value) formats the quiver arrows with any quiver properties.

itslive_quiver(...,'density','DensityFactor') specifies the density of the arrows. Default DensityFactor is 75, meaning hypot(Nrows,Ncols)=75, but if your plot is too crowded you may specify a lower DensityFactor (and/or adjust the markersize).

h = itslive_quiver(...) returns a handle h of the plotted quiver object.

Example 1: Simple

Always set the axis limits of your area of interest before calling itslive_quiver. Below, we zoom to the area surrounding Jakobshavn Glacier, Greenland, then call itslive_quiver and specify Region 5 for Greenland. I'm also plotting an optional basemap underneath for context, which you can get from my plot_basemap repository.

figure
axis([-206557    -129930   -2296636   -2258698])
itslive_quiver(5) 
plot_basemap('epsg',3413) % optional 

exportgraphics(gcf,'itslive_quiver_documentation_jakobshavn_simple.jpg')

Example 2: Formatted arrows

Repeat the example above, but this time make the arrows red and thick:

figure
axis([-206557    -129930   -2296636   -2258698])
itslive_quiver(5, 'r', 'linewidth',2) 
plot_basemap('epsg',3413) % optional 

exportgraphics(gcf,'itslive_quiver_documentation_jakobshavn_formatted.jpg')

Example 3: Arrow density

Increase the density of arrows by specifying a number greater than the default 75:

figure
axis([-206557    -129930   -2296636   -2258698])
q = itslive_quiver(5, 'density', 150); 
plot_basemap('epsg',3413) % optional 

exportgraphics(gcf,'itslive_quiver_documentation_jakobshavn_dense.jpg')

Above, we returned a handle q for the quiver object. You can adjust the color, length, or other properties by setting values in q:

q.Color = [0 0 0];     % make arrows black
q.AutoScaleFactor = 5; % make arrows long

exportgraphics(gcf,'itslive_quiver_documentation_jakobshavn_dense_long.jpg')

Author Info

The MATLAB functions in this repo and this documentation were written by Chad A. Greene of NASA/JPL. The NASA MEaSUREs ITS_LIVE project is by Alex S. Gardner and the ITS_LIVE team.