Update 09-vector-when-data-dont-line-up-crs.Rmd

minor changes

episodes/09-vector-when-data-dont-line-up-crs.Rmd

@@ -142,7 +142,7 @@ boundaries and country boundaries.
 ```{r us-boundaries-thickness}
 ggplot() +
   geom_sf(data = state_boundary_US, color = "gray60") +
-  geom_sf(data = country_boundary_US, color = "black",alpha = 0.25,size = 5)
+  geom_sf(data = country_boundary_US, color = "black",alpha = 0.25,size = 5) +
   ggtitle("Map of Contiguous US State Boundaries") +
   coord_sf()
 ```
@@ -155,7 +155,7 @@ First let's look at the CRS of our tower location object:
 st_crs(point_HARV)$proj4string
 ```
 
-Our project string for `DSM_HARV` specifies the UTM projection as follows:
+Our project string for `point_HARV` specifies the UTM projection as follows:
 
 `+proj=utm +zone=18 +datum=WGS84 +units=m +no_defs`
 
@@ -185,8 +185,7 @@ the lat/long projection as follows:
   coordinate system
 - **datum=WGS84:** the datum WGS84 (the datum refers to the  0,0 reference for
   the coordinate system used in the projection)
-- **ellps=WGS84:** the ellipsoid (how the earth's roundness is calculated)
-  is WGS84
+- **no_defs:** ensures that no defaults are used, but this is now obsolete
 
 Note that there are no specified units above. This is because this geographic
 coordinate reference system is in latitude and longitude which is most often