Using one world file for multiple rasters

Question

I have 400 PNG files all of the same area that are not gereferenced. I have gereferenced one of them and want to use the world file for all the others. I could copy it and rename the files but that will take forever. It there a way in QGIS to point the png files to a worldfile?

Answer 1

Here's how I'd do it using shell script.

Here's a folder with a bunch of .png files, and a folder called world which has a single world file in it.

.
├── arg.png
├── f1.png
├── f2.png
├── f3.png
├── world
│   └── f2.pngw
└── zz.png

I've set things up like this, temporarily separating f2.png from its world file just to make things a bit cleaner for the next step. Which is to run the following command from my terminal:

for f in *.png ; do cp world/f2.pngw ${f}w ; done

and now my folder looks like this:

.
├── arg.png
├── arg.pngw
├── f1.png
├── f1.pngw
├── f2.png
├── f2.pngw
├── f3.png
├── f3.pngw
├── world
│   └── f2.pngw
├── zz.png
└── zz.pngw

Every png has a pngw copied from the one in world/f2.pngw.

This for line works by looping over all files that match *.png and executing cp world/f2.pngw ${f}w, where ${f} is the png file name being worked on. Hence it does:

cp ./world/f1.pngw ./f1.pngw
cp ./world/f1.pngw ./zz.pngw
cp ./world/f1.pngw ./arg.pngw
cp ./world/f1.pngw ./f2.pngw

and so on for all the png files, even if there's 400, in one go.

This should work from Mac and Linux terminals, and it is possible to install something that will do exactly this in Windows, although I forget what its called these days (Windows Linux Subsystem or something???)