Error: Bias grid cannot be used with SWD-format background

[Paul Brewin]

Hi - Any idea why I'm getting this error?  I'm using a raster stack for environmental data (pred) and csv of lat/lons for the occurrence data (occ), and biasfile is a raster.  The full line is me_1 <- maxent(pred, occ, args='biasfile=bias_file').  It works without the biasfile arg.  Have searched up and down the internet - no joy.  Any help would be amazing, thanks!

[Veronica Frans]

Hi Paul,

I'm pretty sure you need to say exactly where that file is located for it to work. Try something like:

args='biasfile=D:\\paul_folder\\bias_file.csv'

 

And if you have more args, be sure to concatenate them. 

args=c()

Although you're using dismo, Maxent is still running via Java. Perhaps you can double-check the specific structure of each of the additional arguments via the help section in the Maxent GUI, as well.

Hope this helps.

Veronica Frans

On Sat, Nov 24, 2018, 09:37 Paul Brewin <pebr...@gmail.com wrote:

Hi - Any idea why I'm getting this error?  I'm using a raster stack for environmental data (pred) and csv of lat/lons for the occurrence data (occ), and biasfile is a raster.  The full line is me_1 <- maxent(pred, occ, args='biasfile=bias_file').  It works without the biasfile arg.  Have searched up and down the internet - no joy.  Any help would be amazing, thanks!

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[Paul Brewin]

Thanks Veronica.  Good suggestion, but didn't work unfortunately.  I tried a few different things around your suggestion as well like using double back slashes instead of forward slashes.  I've got other arguments coded in ok as well. 

I noted that in your example you've got the bias_file.csv and not a raster? 

I also found this post https://github.com/bobmuscarella/ENMeval/issues/30

where it says down the page that biasfile is not implemented in dismo -so i'm thinking maybe that's part of the problem but that's from 2015, but other's have had it working like here https://tinyurl.com/y9zfedk2  I've asked the author of this post as well.

Its seems to me that the problem is that maxent() thinks that I'm using as SWD background file?

Cheers

Paul

[Paul Brewin]

Hi again - still no joy by a workaround can be found here

https://groups.google.com/forum/#!msg/Maxent/kUZTkSiDxbU/i_-cDR4aN8MJ

cheers

Paul

[Veronica Frans]

Hi Paul,

Sorry my advice didn't work out. I forgot to mention that it was my best guess at making it work, since I'd never used a bias file myself, but had used other arguments. 

Still interesting that it didn't work... Haven't been on my laptop these days so I can't test anything at the moment... 

Nevertheless, thanks for updating the forum on a solution, even though it was a work-around. It's good for others to refer to in the future. :-)

Cheers,

Veronica