如何从速度数据集创建向量图? [英] how to create vectorplot from velocity dataset?
问题描述
与我之前有关的问题有关,请根据其中的两个栅格对象计算atan2 R?.可以根据以下等式创建矢量绘图,在其中以一组箭头(例如Matlab中的颤动)显示速度(坡度)和方向(纵横比):
Related to my previous question about calculate atan2 from two raster object in R?. It's possible to create a vector plot where the speed (slope) and direction (aspect) is displayed with a set of arrows (e.g. quiver in Matlab) based on this equation:
对于速度:ws<-sqrt(u ^ 2 + v ^ 2)
for speed : ws <- sqrt(u^2+v^2)
方向:wd<-(180/pi)*(atan2(u,v))
for direction : wd <- (180/pi)*(atan2(u,v))
我的数据集样本可以下载这里
u <- raster(flname, varname = 'U')
v <- raster(flname, varname = 'V')
uv <- stack(u,v)
我使用rasterVis软件包来绘制图,但结果不适合.
I used rasterVis package to figure the plot, but the result is not fit.
library(rasterVis)
vectorplot(uv)
推荐答案
从vectorplot
的帮助页面:
如果'isField ='dXY'''对象'必须是具有两个图层的栅格* 代表水平和垂直分量, 分别.
If ‘isField='dXY'’ ‘object’ must be a Raster* with two layers representing the horizontal and the vertical components, respectively.
因此,解决方案是:
vectorplot(uv, isField = 'dXY')
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