For now, clip anglingXwater events to exclude lakes outside the conti…

…nental US.

Later, this should probably happen in spatialjoin.r
See Issue #5.

code/spatialjoin_fixer.r

@@ -0,0 +1,37 @@
+###
+### Clip the current anglingXwater.csv events to ones from continental US
+###   someday this should happen in spatialjoin.r.  see issue #5.
+###   for now, we'll just export a US-clipped version of anglingXwater for further analyses
+###
+
+library(rgdal)
+# library(raster)
+# library(rgeos)
+library(sf)
+
+## Import angling x water data (output of spatialjoin.r)
+##   and create spatial data frame
+axw_raw <- read.csv("analysis/anglingXwater.csv")
+axw <- SpatialPointsDataFrame(axw_raw[ ,c("longitude_cent","latitude_cent")], axw_raw, proj4string=CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))
+
+
+## Import US border shape
+##   representing the continental US plus the great lakes
+##   created by merging and dissolving the US census border with border of great lakes
+usa <- readOGR("data", "cb_2017_us_state_20m_N_hydro_p_diss")
+usa_wgs <- spTransform(usa, CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))
+
+## Join angling events to continental USA shape
+angusa <- over(axw, usa_wgs)
+
+## Drop records that aren't in USA
+axw_usa <- axw_raw[!is.na(angusa), ]
+
+## Write an updated anglingXwater for events in USA (and great lakes)
+write.csv(axw_usa, "./analysis/anglingXwater_usa.csv", row.names=F)
+
+## QAQC
+plot(usa_wgs)
+plot(axw, add=T)
+plot(axw[which(is.na(angusa)), ], add=T, col="red")
+