VecStatGraphs2D, A Tool for the Analysis of Two-Dimensional Vector Data: An Example Using QuikSCAT Ocean Winds

Abstract

Circular or directional data are used in disciplines such as meteorology, geomatics, biology, and geology. The analysis of angular data requires special methods that are available in some statistical packages. However, these tools analyze only the angular values and do not include the vector modules, assuming unit vectors in all cases. In this letter, an open-source graphic and statistical package, i.e., VecStatGraphs2D, is described. It works in the R environment and provides statistics and graphics for modules (linear) and azimuths (circular), as well as graphics for the joint analysis of modules and azimuths. QuikSCAT satellite wind data are used to demonstrate some features of the package. QuikSCAT data are non-unit-length vectors, where both azimuth and magnitude (speed) are derived from u and v vector components (vector projections over the x-and y-axes). The example is used to show the seasonal change of winds in the Intertropical Convergence Zone, a key area in the ocean bird migration from the North to South Atlantic oceans.

Desarrollo y validación de una estación meteorológica automatizada de bajo costo dirigida a agricultura

“…The magnitude and direction of the vectors in two different studies were analysed (Carvahalo et al, 2013): a study of Pearson correlation of the magnitudes with SPSS, and a correlation study circular by Jammalamadaka-SenGupta (Pewsey and Ruxton, 2013) using the free software R and the circular added. Vector density maps were generated using the addition of R vec Stat Graphs 2D (Rodríguez et al, 2014) to observe the frequency of vectors and complement the results of the correlations.…”

“…Se analizaron la magnitud y la dirección de los vectores en dos estudios diferentes (Carvahalo et al, 2013): un estudio de correlación de Pearson de las magnitudes con SPSS, y un estudio de correlación circular de Jammalamadaka-SenGupta (Pewsey y Ruxton, 2013) utilizando el software libre R y el añadido circular. Se generaron mapas de densidad vectorial utilizando el añadido de R vecStatGraphs2D (Rodríguez et al, 2014) para observar la frecuencia de los vectores y complementar los resultados de las correlaciones.…”

Circular Statistics Applied to the Study of the Solar Radiation Potential of Rooftops in a Medium-Sized City

“…Circular statistics or directional statistics address angular data, axes, or vectors and enable an analysis of orientations in two dimensions. Circular statistics are applied in a variety of disciplines, such as biology [32], meteorology (wind analysis) [33], geography [34], remote sensing [35] and cartography [36], to name a few. The analysis of angular data requires special methods because directional data are different from linear data.…”

“…Oriana [43] is a commercial application written for Microsoft Windows that calculates statistics and graphics for circular data, angles or directions measured in degrees, time of day, month of year, etc. VecStatGraphs2D [33] is an R package [44], designed for the statistical analysis of 2D vectors, that generates a set of statistics for both linear data (e.g., the arithmetic mean, standard deviation, variance, and skewness coefficient) and circular data (e.g., the mean azimuth, mean module, and circular variance), and it also generates graphics to address circular data. IBM SPSS [45] is a platform that offers advanced statistical analyses, and it is especially used in the social sciences field.…”

Directional Statistics in Solar Potential of Rooftops at Three Different Neighborhoods of a Medium Size City

“…To perform the statistical analysis two applications were used, Oriana [8] and VecStatGraphs2D [9], that it is an R package.…”