What is the "spatial information" in convolutional neural network deep learning research papers always claim that deeper layers of CNN have good "semantic information" but poor "spatial information". What is the spatial information exactly. Is that some activations in deeper layers?
Spatial Information refers to information having location-based relation with other information.

For example,
00100
01100
00100
00100

This looks like the number "1".

If this was represented in a single line,
001100011100001100001100

It wouldn't be recognizable.

Earlier layers of CNN are convolutional layers, which take into account the image as a 2D (spatial) information. Whereas, the deeper layers flatten that (convoluted) information.