Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
717 
A hydrological comparison of Landsat TM, Landsat MSS 
and black & white aerial photography 
M.J.France & P.D.Hedges 
Aston University, UK 
ABSTRACT: Landsat TM is evaluated for its accuracy in delineating, 
mapping and measuring, water bodies, drainage networks, catchment 
areas and landcover. A comparison is made with results from 
Landsat MSS imagery and 1:50000 scale black & white aerial 
photography, for the same area in North Wales, U.K. 
Landsat TM is found to have significant advantages over Landsat MSS 
for recording drainage network information. Lakes as small as 0.6 
hectares can be identified using Landsat TM imagery and the 
delineation of small streams aids in accurately defining catchment 
boundaries. 
1 INTRODUCTION 
Satellite remote sensing provides an attractive 
way of collecting hydrological data and is of 
particular significance in areas where traditional 
methods of hydrological data collection are 
inadequate or impractical. The data can be used 
as input to morphology or landcover -based 
hydrological models. 
This research is directed at a comparison of 
Landsat Multispectral Scanner (Landsat MSS) 
imagery, Landsat Thematic Mapper ( Landsat TM) 
imagery, 1:50000 scale Black & White aerial 
photography and the 1:50000 scale Ordnance Survey 
map of the area, using the same test area. 
Earlier work on Landsat MSS, with its 80m 
resolution found encouraging results in areas of 
high relief (Rango et al., 1975; Killpack and 
McCoy, 1981) but limited success in most British 
situations . It was thought that the Landsat TM 
with its greater spatial and spectral resolution 
might prove more successful. 
Table 1. Comparison of Landsat TM and MSS sensor 
characteristics. 
TM Data 
MSS Data 
Spectral 
Spatial 
Spectral 
Spatial 
Band 
range ,pm 
resoln. ,m 
Band 
range ,yu m 
resoln.,m 
1 
0.45-0.52 
30 
4 
0.5-0.6 
80 
2 
0.52-0.60 
30 
5 
0.6-0.7 
80 
3 
0.63-0.69 
30 
6 
0.7-0.8 
80 
4 
0.76-0.90 
30 
7 
0.8-1.1 
80 
5 
1.55-1.75 
30 
6 
10.4-12. 
120 
7 
2.08-2.35 
30 
Work concentrated particularly on the Landsat TM 
imagery as there is little relevant published 
material on this imagery. Specific aims were: 
1. To ascertain the efficiency of drainage mapping 
using Landsat TM imagery. 
2. To specify the most useful image enhancements 
for this purpose. 
3. To compare the efficiency of interpretation of 
Landsat MSS imagery, Landsat TM imagery and Black 
& White aerial photography. 
The area selected for this research, some 235km 2 
in extent, is the Dolgellau and Coed-y-Brenin area 
of North Wales, U.K. (see Figure 1). The area is, 
in the main, an upland region of hills and 
mountains with a maximum elevation of 754 metres. 
A Lowland valley runs across the southern part of 
the region. Streams and rivers in the area are 
bordered by various lowland and upland vegetation 
types and frequently pass through forests or 
woodland , giving opportunity for the examination 
of several water/vegetation interfaces. 
Figure 1. Location of study area. 
2 METHOD 
Four Landsat MSS images, with minimal or no cloud 
cover, were available for the area, the best of 
which is a scene from May 1977. One Landsat TM 
quarter scene from July 1984, with little cloud 
coverage was available from the U.K. National 
Remote Sensing Centre. These images were enhanced 
using the GEMS image processors at NRSC, 
Farnborough, and Silsoe College, Bedford and an 
I 2 S system at NERC, Swindon. 
Image enhancement was mainly directed at the 
Landsat TM data as little published work exists on 
the processing of this material. Individual bands, 
band combinations, principal components analysis 
and several edge enhancement techniques were 
evaluated for their enhancement of linear water 
bodies. Similar techniques were applied to the 
Landsat MSS imagery. Hard-copies of enhancements