删除零并记录y轴，以空间点数据框为x轴

Question

I have two variables that I want to plot. One is Abundance (y axis), and the other is Northing. I have created a spatial points data frame, converting Northing into Latitude (x axis).

Usually this would be fine for me to plot, however, I want to remove the zeros from and log my Abundance variable (y axis). How could I do this without getting an error like "variable lengths different"?

plot(SP_df$Latitude, df$Abundance)

abline(lm(df$Abundance ~ SP_df$Latitude))

Answer 1

Taking the example from @qdread, you can index a SpatialPointsDataFrame just like any other dataframe.

Create the reprex dataframe:

x <- SpatialPointsDataFrame(coords = data.frame(x = 1:10,y = 1:10),
                        data = data.frame(lat = 1:10,abu = exp(0:9)))

Index the dataframe and log transform abundance column:

x.above.zero <- x[x$abu>0,]
x.above.zero$logAbu <- log(x.above.zero$abu)

You can then plot it as you wanted.

plot(x.above.zero$lat, x.above.zero$logAbu)
abline(lm(x.above.zero$logAbu~x.above.zero$lat))

In general, keeping the metadata tied to the spatial data by keeping it all in one object avoids this problem.