How to make the resolutions and spatial extents of ESRI/ASCII grid rasters exactly the same

This tutorial shows you how to make the resolutions and spatial extents of ESRI/ASCII grid rasters exactly the same. This is an important step for performing ecological niche modeling (also known as species distribution modeling). If the environmental layers (typically in the form of rasters) do not have exactly the same resolution and spatial extent, the modeling will fail! Often when you make your own rasters, even when you make them exactly the same way, they will still have slight differences in the resolutions and/or spatial extents. That is why this tutorial is so vital.

This tutorial uses Rstudio under Ubuntu Linux version 20.04.

This tutorial assumes you already have R and Rstudio installed. See my tutorial for installing those software:

Want to learn how to make and modify rasters? See my other tutorials:

This tutorial assumes you are using Ubuntu Linux version 20.04 as your operating system. If you do not have a computer running Ubuntu, fear not. You can install Ubuntu as a virtual machine within your current operating system. It is all free.
The instructions for Windows computers are here:
The instructions for Mac computers are here (from 0:00 to 5:37):

FYI:
I have made a Linux virtual machine that is pre-configured with population genetics and ecological niche modeling programs. I have made videos explaining how to hook up this virtual machine within your Mac or Windows computer, so that you can start using the pre-configured software without having to install any of them (and even without having to install Ubuntu Linux!).

[tauheedmarwat]

Hi, thank you for explaining everything in a very systematic way and with great detail. Unfortunately, I got this error for the given code "> slopb <- resample(slop, bio1)
Error in .intersectExtent(x, y, validate = TRUE) :
Objects do not intersect".

[homerong]

Hi, Prof. Banta,

Thanks for sharing your tutorial vidoes!
I would like to ask what the afldtx.asc and bdtx.asc files are and how you prepared those.

[girmatimer]

Dear Prof.Banat
All the tutorials are very interesting and i am learning a lot. would you tell how to download or prepare ASCII adjust files 4-1-19.R

[smritishrestha]

i dont know why, i did the same thing but the extent is a bit different

[whitneyholeva]

Hi Josh, thank you for all of the excellent tutorials! Is this something that we could run on our own Windows machine rather than the Linux virtual machine? The reason I ask is that I have gone through all of the steps to download the virtual machine, but I am having a hard time installing the raster package in R on the virtual machine. I have tried multiple times and each time get an error message regarding the package 'terra' when trying to install the package 'raster' so I cannot open the raster library. I already have the 'raster' package installed on my own machine. Thanks again!