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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
MONITORING OF AGRICULTURAL LANDSCAPE IN NORWAY 
H.G. Wallin, G. Engan 
Norwegian Forest and Landscape Institute, p.b. 115, N-1431 As, Norway — (hgw, gue)@skogoglandskap.no 
KEY WORDS: Agriculture, Resources, Monitoring, Change Detection, Aerial, Stereoscopic. 
ABSTRACT: 
An overall societal aim is to ensure a sustainable use and management of agricultural landscapes. This requires continuous delivery 
of reliable and up-to-date information to decision-makers. To be able to deliver this information, a monitoring program for 
agricultural landscapes was initiated in Norway 13 years ago. The program documents and reports on land use / land cover changes 
from data captured through interpretation of true colour aerial photos using stereo instruments. The monitoring programme is based 
on a sample of 1000 squares of 1 x 1 km and the entire sample of squares is photographed over a five-year period. Each square is 
then mapped repeatedly every fifth year to record changes. 
Aerial photo interpretation is based on a custom classification system which is built up hierarchically, with three levels. The first 
level comprises seven land type classes: Agricultural land, Bare ground, Semi-natural open vegetation, Unforested wetland 
vegetation, Forest, Urban areas and Water. These land classes are further divided into 24 land types at level two, and approximately 
100 land types at level 3. In addition to land type units we map both line elements like stone fences and point elements like buildings 
and solitary threes. By use of indicators that describe status and change focusing on themes of particular policy interest, we can 
report on whether policy aims are being fulfilled or not. Four indicator themes have been in focus hitherto: landscape spatial 
structure, biological diversity, cultural heritage and accessibility. 
Our data is stored in databases and most of the data quality check/structure process and analyses are now being made in open source 
software like PostGIS and PostSQL. To assess the accuracy of the photo-interpretation, ground truthing is carried out on 10 % of the 
squares. The results of this operation document the benefits of having access to photos of the same area from two different years. 
The program is designed first and foremost to provide reliable statistics at a national level but the aim is also to report at regional 
levels — for example for counties or for agricultural landscape regions. The national coverage and application of standardized 
methods enable frequent updating. This method is cost effective and enables us to quantify changes in landscape qualities as well as 
adapting the programme to take account of e.g. new findings on relevant indicators. 
1. INTRODUCTION Several controls are carried out on the captured data, e.g. illegal 
codes and missing features. 10 % of the squares are checked 
1.1 Landscape monitoring through a field control. 
To ensure a sustainable use and management of agricultural 2. METHODES 
landscape the decision-makers need reliable and up-to-date 
information. Interpretation of land use / land cover from aerial 2.1 Photos 
photos plays a major role in studies of landscape changes in 
Norway. The mapping is done by the means of stereo instruments and 
true color photos. Since the program started in 1998 analogue 
  
A monitoring program where the main aim is to register this 
changes started in 1998. This program is based on a sample of 
1000 squares of 1 x 1 km. The squares are photographed each 
fifth year and the land use / land cover situation is digitized in 
stereo with a classification system that covers area, lines, points 
and accessibility (Strand, 2002). 
By use of indicators that describe status and change focusing on 
themes of particular policy interest, we can report on whether 
policy aims are being fulfilled or not. Four indicator themes 
have been in focus hitherto: landscape spatial structure, 
biological diversity, cultural heritage and accessibility. 
Cultural heritage from existing register is displayed in the stereo 
model so that the interpreter will update the situation for each 
element that is registered. A lot of the cultural heritage (as 
barrows) is hidden by trees. The classification system gives the 
Interpreter the opportunity to use different types of codes 
describing the situation. 
instruments have been replaced with digital instruments. The 
airborn cameras have also changed from film based to digital 
CCD. This has improved the quality of the aerial images 
incredibly. 
To interpret a photo there are some things you need to know. 
The date the photo is taken is very important. The nature looks 
differently in spring, summer and early autumn. There are also 
different types of farming in different parts of Norway, so the 
operator needs to know where in the country the photo is taken. 
A real challenge is to distinguish between the different stages 
and activities: from full activity to abandonedfarms. 
The scale of the photos has also changed over the period of 
registration. In Norway we now have a national program for full 
photo cover with an interval of five to six years. The 
agricultural monitoring program (3Q) has decided to use these 
photos because of the cost-effectiveness. The ground sample 
distance (GSD) varies from 30 to 50 cm.