background vs. absence points / standardize terminology

[frousseu]

Hi!

I was about to do a pull request to change line 136 of the maxent.R file to change the "of the presence points" for "of the absence points", but then I noticed that both absence and background are used throughout the package and I think it would probably be better to standardize the name used and background would be preferable to absence (e.g. the aargument for background, but nbg for the number of background points, etc.).

I could work on a pull request to change the absences for backgrounds throughout the package when it seems justified. Let me know if you wish me to do so.

Cheers,
François

[rhijmans]

Thanks for pointing that out; but some of this is by design. I think the general concept is "absence", but since Maxent is explicitly designed/described as using "background" data, I think it is better to use that term in that context (which I attempted to do with 6f2c17b)

[frousseu]

I think there are a couple more places and files where it could be changed (which I could still look for!), but this is an improvement. For line 136, it still needs to be changed to background instead of presence since the warning concerns the background points that were removed because of NAs in predictors.

[frousseu]

Thank you!