Lesson 1 updated by replacing calls to raster and rgdal packages with terra. #368

Author: albhasan

episodes/01-raster-structure.Rmd

@@ -269,7 +269,7 @@ as follows:
 Note that the zone is unique to the UTM projection. Not all CRSs will have a
 zone. Image source: Chrismurf at English Wikipedia, via [Wikimedia Commons](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system#/media/File:Utm-zones-USA.svg) (CC-BY).
 
-![The UTM zones across the continental United States. From: https://upload.wikimedia.org/wikipedia/commons/8/8d/Utm-zones-USA.svg](fig/Utm-zones-USA.svg)
+![The UTM zones across the continental United States. From: https://upload.wikimedia.org/wikipedia/commons/8/8d/Utm-zones-USA.svg](fig/Utm-zones-USA.svg){alt='UTM zones in the USA.'}
 
 ## Calculate Raster Min and Max Values