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LANDSAT-DATA FOR DISTRIBUTED HYDROLOGICAL MODELS 
by 
L. GOTTSCHALK, I. KRASOVSKAIA 
Department of Hydrology 
University of Uppsala 
751 22 Uppsala Sweden 
and 
J.30.- TALTS 
National Land Survey 
801 12 Gävle Sweden 
ABSTRACT 
The most widely used models in hydrology today are lumped models, but they do 
not answer sufficiently to the present needs of hydrological information for 
water resources planning. Lumped models do not give a possibility to simulate 
state and flows in internal parts of a watershed. When model parameters are 
determined from hydrological and climatological observations with the help 
of statistical methods, the choice of basin is governed by the pattern of the 
observation network and not by the needs of a specific water planning problem. 
The present needs of water information calls for a new generation of distri- 
buted hydrological models. As hydrological and climatological observations are 
not of sufficient density in space to provide the necessary basic information 
for the-distributed models, new types of digital data sources are needed for 
supplementary landscape information. 
Landsat-data has been used to make a classification of thg basin of one of the 
largest lakes in Sweden. The area classified was 8 000 km^ and situated on two 
adjacent satellite paths. 
Together with Landsat-data, digitized map data has been used. The map data was 
obtained by using a raster scanner to convert overlays of maps in 1:250 000 
into digital form. 
Landsat-data has then been transformad to the map grid system and the two data 
sets have been used together in a maximum-likelihood classification into 34 
categories representing water, built up areas, forest, bogs and arable land. 
In the paper the demands of new types of spatial data are discussed as well as 
methods of data acquisition with examples from a hydrological project in Sweden. 
Examples of the use of the digital map data and satellite images to describe 
these are given. 
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