Spatial Data and GIS - Vector Data

Extract raster values using vector boundaries in R

This lesson reviews how to extract pixels from a raster dataset using a vector boundary. We can use the extracted pixels to calculate mean and max tree height for a study area (in this case a field site where we measured tree heights on the ground. Finally we will compare tree heights derived from lidar data compared to tree height measured by humans on the ground.

last updated: 18 Sep 2017

GIS in R: Plot spatial data and create custom legends in R

In this lesson we break down the steps required to create a custom legend for spatial data in R. We discuss creating unique symbols per category, customizing colors and placing your legend outside of the plot using the xpd argument combined with x,y placement and margin settings.

last updated: 18 Sep 2017

GIS in R: Projected vs geographic Coordinate Reference Systems

This tutorial describes key differences between projected and geographic coordinate reference systems (CRSs). We focus on the Universal Trans Mercator (UTM) projected Coordinate Reference which divides the globe into zones to optimize projection results in each zone and WGS84 which is a geographic (latitude and longitude) CRS. It also briefly introduces the concept of a datum.

last updated: 18 Sep 2017