Chapter 5 — Question 1

Compare

multispectral

scanner

data

with

scanned

aerial

photographs.

Which similarities and differences can you identify?

Answer

Differences and si-
milarities

MSS data

Scanned

Aerial

Photo-

graphy

Origin

detectors

analogue (paper/negative)

Original form

pixels

lines per inch / dots per inch

Spatial resolution

1m (up to 1km)

centimetres to metres

Spectral range

UV-TIR

UV-NIR (’real’ optical range;
through lenses)

Radiometric resolu-
tion

system dependent (usually
2

8

)

system dependent (usually
2

8

)

Coverage (area size)

local up to global (half disk
of the earth)

local

Covered

spectrum

range

0.2 µm–15 µm , 1 mm–1 m

0.4 µm–0.9 µm

Pixel size

usually 1 m–30 m (officially
1 m–1 km)

usually 1m to a few metres
(varies, see Section 4.3.5)

Quantisation

data independent

data independent

Geometric quality

function of incidence angle,
height, application needs . . .

function of roll, pitch and
yaw variations, and of flight
height

?

CCDs are ‘scanned’ photographs indeed, but this comparison should be res-

tricted to scanned AP which originates from hardcopy AP (negative or positive).
Refer to Sections 3.4, 5.1–5.3.2 and 4.3.5.

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