The photos are taken overlooking one of the main bridges in Munich from the top of a small rise, enabling a broad view of the city and including good foreground detail and a substantial amount of sky.
The first image was taken by simply pointing the camera and hitting the trigger
5D2, 24-105mm, 24mm, f/4, 1/1000, ISO 400
This is clearly underexposed as a result of the large portions of the images that are more or less white. Increasing the exposure by one and a half stops produced a better balanced image with white snow, but with the sky nearly completely blown out
5D2, 24-105mm, 24mm, f/4, 1/350, ISO 400
Now fitting the grad filters at increasing strengths I produced the following 3 images. In each case I have maintained the exposure manually at the same value as the previous image
The middle image with the 2 stop filter preserves the cloud structure best of the images.
The indoor exercise was interesting, I had not considered using a grad filter on its side to darken part of a room. I used my home office to produce the suggested image. I fixed my camera at one end of the room, with the window to the left and took the following image using the cameras metering:
5D2, 24-105mm, 24mm, f/8, 20s, ISO 100
I immediately realized that because my room was fairly small I was seeing the opposite affect to the one suggested in the text. The door on the right side of the frame was strongly reflecting the light and was being washed out in the image. I used a hand held meter to check the incident light level across the room. Keeping the aperture and ISO at f/8 and 100 respectively, I measure the following
Left hand wall: 30s
rear book case: 25s
right book case 10s
right hand door: 4s
So the small room was better illuminated opposite the window. To rectify this I tried mounting the grad filter with the dark part to the right of the image. I maintained the exposure as before and captured the following two images with the 1 and 2 stop grad filters
In each case I tried to align the filter edge along the right corner of the room. The 1 stop filter balances the image well, bringing the brightness of the right hand book case down to that of the rear one and preventing the door from being washed out. At 2 stops the door becomes too grey and the right hand book case is now darker than it needs to be.