Working with Geospatial Data: References

Shapefile metadata include geometry type, CRS, and extent.

Load spatial objects into R with the st_read() function.

Spatial objects can be plotted directly with ggplot using the geom_sf() function. No need to convert to a dataframe.

Spatial objects in sf are similar to standard data frames and can be manipulated using the same functions.

Almost any feature of a plot can be customized using the various functions and options in the ggplot2 package.

Know the projection (if any) of your point data prior to converting to a spatial object.

Convert a data frame to an sf object using the st_as_sf() function.

Export an sf object as text using the st_write() function.

The GeoTIFF file format includes metadata about the raster data.

To plot raster data with the ggplot2 package, we need to convert it to a dataframe.

R stores CRS information in the Proj4 format.

Be careful when dealing with missing or bad data values.

Use the crop() function to crop a raster object.

Use the extract() function to extract pixels from a raster object that fall within a particular extent boundary.

Use the extent() function to define an extent.