Contents
How to get a spatialpolygon from a list?
After that, do as(mySpatialPolygon, “SpatialPolygonsDataFrame”), and you got a SpatialPolygonsDataFrame.– lukeAOct 23 ’17 at 13:18 Unfortuneatly my data is slightly different from the one in the example. I don´t have seperate SpatialPolygons but just a list of Spatial Polygons.
How to create a spatial polygon in R?
Most people deal with SpatialPolygon files that have already been created and are read into R via a shapefile. In the next portion of this tutorial we’ll download a SpatialPolygonDataFrame that contains US State boundaries. We can get the data directly from within R using the getData function available in the raster package.
What’s the difference between spatial and spatialpolygonsdataframe?
The difference between SpatialPolygons and SpatialPolygonsDataFrame are the attributes that are associated with the polygons. SpatialPolygonsDataFrames have additional information associated with the polygon (e.g., site, year, individual, etc.) while SpatialPolygons contain only the spatial information (vertices) about the polygon.
How to create a spatial polygon layer from scratch?
Let’s begin by creating a set spatial polygons layer from scratch. We’ll use the sp package to make a SpatialPolygons object. First we need to create a set of XY coordinates that represent the vertices of a polygon. We’ll use use some randomly generated XY coordinates.
When to use lapply, sapply, Tapply functions?
It is useful for operations on list objects and returns a list object of same length of original set. sapply () function does the same job as lapply () function but returns a vector. We can measure the minimum speed and stopping distances of cars from the cars dataset.
What’s the trick to repeating things in lapply?
The challenge is to identify the parts of your analysis that stay the same and those that differ for each call of the function. The trick to using lapply is to recognise that only one item can differ between different function calls.
When to use the generic looping function in R?
This is crucial. If each each iteration is independent, then you can cycle through them in whatever order you like. Generally, we argue that you should only use the generic looping functions for, while, and repeat when the order or operations is important. Otherwise reach for one of the apply tools.