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NCL Graphics: Vector Effects

This page shows how to customize vectors using various resources. Here's a sample of a few of them. You can see a full list on the vector resource page.

veceff_1.ncl: This script compares a default vector plot (first frame) with vector plots that have been customized (second and third frames). The second frame customizes the plot by setting the following resources:

The third frame increases the line thickness of the vectors using vcLineArrowThicknessF. This can be especially important if you need to make images large for presentations or posters.

veceff_2.ncl: Sets the size of the arrow heads.

This example is similar to the previous one, except the size of the arrow heads are made the same by setting vcLineArrowHeadMinSizeF and vcLineArrowHeadMaxSizeF to the same value.

veceff_3.ncl: Controlling the appearance of vector arrow heads.

vcFillArrowFillColor and vcFillArrowEdgeColor enable you to set the color and outline color of filled vectors.

The second and third frames show how to further control the appearance of the arrow heads using a whole set of resources: vcFillArrowWidthF, vcFillArrowMinFracWidthF, and vcFillArrowHeadMinFracXF.

veceff_4.ncl: Thinning vectors.

Use vcMinDistanceF to thin your vectors based the distance between vectors.

You can also thin your vectors simply by striding the data:

  vector = gsn_csm_vector(wks,u(::2,::2),v(::2,::2),res)

newcolor_8.ncl: This example demonstrates drawing partially transparent filled vectors.

The vectors are drawn fully opaque in the first frame. In the second frame, vcGlyphOpacityF is set to 0.3.