National Land Survey Research Articles

SPECIES-SPECIFIC FOREST VARIABLE ESTIMATION USING NON-PARAMETRIC MODELING OF MULTI-SPECTRAL PHOTOGRAMMETRIC POINT CLOUD DATA

Abstract. The recent development in software for automatic photogrammetric processing of multispectral aerial imagery, and the growing nation-wide availability of Digital Elevation Model (DEM) data, are about to revolutionize data capture for forest management planning in Scandinavia. Using only already available aerial imagery and ALS-assessed DEM data, raster estimates of the forest variables mean tree height, basal area, total stem volume, and species-specific stem volumes were produced and evaluated. The study was conducted at a coniferous hemi-boreal test site in southern Sweden (lat. 58° N, long. 13° E). Digital aerial images from the Zeiss/Intergraph Digital Mapping Camera system were used to produce 3D point-cloud data with spectral information. Metrics were calculated for 696 field plots (10 m radius) from point-cloud data and used in k-MSN to estimate forest variables. For these stands, the tree height ranged from 1.4 to 33.0 m (18.1 m mean), stem volume from 0 to 829 m3 ha-1 (249 m3 ha-1 mean) and basal area from 0 to 62.2 m2 ha-1 (26.1 m2 ha-1 mean), with mean stand size of 2.8 ha. Estimates made using digital aerial images corresponding to the standard acquisition of the Swedish National Land Survey (Lantmäteriet) showed RMSEs (in percent of the surveyed stand mean) of 7.5% for tree height, 11.4% for basal area, 13.2% for total stem volume, 90.6% for pine stem volume, 26.4 for spruce stem volume, and 72.6% for deciduous stem volume. The results imply that photogrammetric matching of digital aerial images has significant potential for operational use in forestry.

Land-use changes and policy dimension driving forces in China: Present, trend and future

China has extremely scarce land resources compared to the world average. There is an urgent need for studies of the current situation and the trends in land-use change and assessment of the performance of land policies in China. Assessment of land-use change has long been hindered by a lack of accurate and reliable data. This paper uses the data obtained from the national land surveys of 1996 and land-use change surveys from 1997 to 2008, to analyze changes in land use and the policy dimension driving forces related to the changes, especially cultivated land, forestry land, grassland, as well as developed land. The aim of this analysis will be to derive the physical, social and economical driving forces of those changes to grasp the trends in land-use change and the effects of land policies and to formulate strategies for the protection and sustainable use of agricultural land. The results indicate that, although the overall change in land use was not large, cultivated land was significantly reduced and developed land rapidly increased. A great deal of high quality cultivated land was changed to developed land and low quality cultivated land generated from unused land, which has resulted in a serious threat to food supplies in China. Predictions using the methods of linear extrapolation and a BP neural network indicate that it is impossible to keep to a target of 0.12 billion hectares of cultivated land in the future under the mode of economic development used between 1996 and 2008. The results also indicate that the implementation of the laws and regulations about controlling the developed land and preserving cultivated land had significant effects on changes in land use, especially cultivated land and developed land. The results suggest that the changes in land use are closely related to economic fluctuation and the enaction and implementation of these land policies had a little time lag for cultivated land protection. There is a pressing need for China to use its limited land resources more efficiently and effectively by enacting or re-enforcing the laws and regulations on land resources protection and economic development, not only for its own growing population, but also the world. Therefore, we must formulate strategies for the protection and sustainable use of agricultural land.

Evaluation of data sources for mapping glacial meltwater features

The meltwater system of disintegrating ice sheets provides an important source of information for the reconstruction of ice-retreat patterns during deglaciation. Recent method development in glacial geomorphology, using satellite imagery and digital elevation models (DEMs) for glacial landform mapping, has predominantly been focused on the identification of lineation and other large-scale accumulation features. Landforms created by meltwater have often been neglected in these efforts. Meltwater features such as channels, deltas and fossil shorelines were traditionally mapped using stereo interpretation of aerial photographs. However, during the transition into the digital era, driven by a wish to cover large areas more economically, meltwater features were lost in most mapping surveys. We have evaluated different sets of satellite images and DEMs for their suitability to map glacial meltwater features (lateral meltwater channels, eskers, deltas, ice-dammed lake drainage channels and fossil shorelines) in comparison with the traditional mapping from aerial photographs. Several sets of satellite images and DEMs were employed to map the landform record of three reference areas, located in northwestern Scotland, northeastern Finland and western Sweden. The employed satellite imagery consisted of Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Satellite Pour l'Observation de la Terre (SPOT) 5 and Indian Remote Sensing (IRS) 1C, and the DEMs used were from NEXTMap Britain, Panorama, National elevation data set of Sweden and National Land Survey of Finland. ASTER images yielded better results than the panchromatic band of Landsat 7 ETM+ in all three regions, despite the same spatial resolution of the data. In agreement with previous studies, this study shows that DEMs display accumulation features such as eskers suitably well. Satellite images are shown to be insufficiently detailed for the interpretation of smaller features such as meltwater channels. Hence, satellite imagery and DEMs of intermediate resolution contain meltwater system information only at a general level that allows for the identification of landforms of medium to large sizes. It is therefore pertinent that data with an appropriate spatial and spectral resolution are accessed to fulfil the need of a particular mapping effort. Stereo interpretation of aerial photographs continues to be an advisable method for local meltwater system reconstructions; alternatively, it can be replaced by mapping from high-resolution DEMs such as NEXTMap Britain. For regional to sub-continental reconstructions, the use of ASTER satellite imagery is recommended, because it provides both spectral and spatial resolutions suitable for the identification of meltwater features on a medium to large scale.

The Use of a VRS-Based Pioneer 3-AT Robot in Pavement Inspections

Abstract This study proposed a framework of the Pioneer 3-AT (P3-AT) autonomous robot for pavement inspection that was integrated with a highly accurate virtual reference station (VRS) positioning technique. The two test sites were 60 km apart; one was rigid pavement and the other was flexible pavement. Two VRS systems were adopted: (1) A VRS system developed by Taiwan Control Signal Co., Limited and (2) Virtual Base Station Real-Time Kinematic (also called e-GPS system) from Taiwan National Land Surveying and Mapping Center. First, the tire pressure and horizontal movement of the P3-AT were calibrated on the two test sites. Then the accuracy of the positioning data provided by VRS to guide the P3-AT was investigated under both static and dynamic conditions at distances of movement from 0.25 to 20 m, to verify the stability and feasibility of this framework. We observed that standard deviations in positioning were less than 0.03 m and rms values were close to prescribed distances in static tests. The reproducible errors were less than 0.03 m in dynamic tests. The results showed that the two VRS systems were able to provide the P3-AT with accurate positioning data on the two test sites. This study also successfully demonstrated the use of the P3-AT in autonomously surveying surface distresses and manholes and its ability to accurately plot slabs on a rigid pavement. Since the P3-AT possesses the properties of low volume, slow speed, flexible modules, and low price, this study confirms that the P3-AT integrated with the VRS positioning technique has the potential to provide significant assistance in automatic pavement inspections of specific areas, such as airports, and for particular purposes, such as Quality Control/Quality Assurance testing.

Calibrating and validating multispectral 3D imaging systems at a permanent test site—case study with an Intergraph DMC

AbstractNovel photogrammetric sensors open up new possibilities for measuring the radiometric and geometric properties of the earth’s surface. To ensure optimal use of these complex, rapidly developing, diverse systems, it is becoming crucial to have a means of calibrating and validating complete imaging systems, and even production lines, in operational conditions. This paper presents a calibration and validation methodology based on a permanent test site (Sjökulla) and demonstrates its use in a calibration and validation campaign for a large‐format photogrammetric imaging system, the Intergraph DMC. The major objective of the campaign was to perform acceptance testing of the new camera system procured by the National Land Survey of Finland. The evaluation proved the high geometric and radiometric performance of the imaging system and demonstrated the potential of spectrodirectional photogrammetric 3D imaging. The usability aspects of test site calibration and validation from the point of view of a mapping organisation were also considered.

Map Design for a Multi-Publishing Framework – Case MenoMaps in Nuuksio National Park

The paper describes the map design process of the MenoMaps project, which aims to create new kinds of maps for supporting outdoor leisure activities, and to carry out research on the utilisation of multi-publishing in a cartographic context. The idea behind a multi-publishing service is that the service is able to deliver different kinds of outdoor maps through a number of channels and at varying scales and designs from a single data core. The data core utilizes integrated data sources, including the Finnish topographic and map databases of the National Land Survey of Finland, as well as datasets from the Nuuksio National Park test environment of the Finnish Geodetic Institute, including high-resolution orthophotos and digital terrain models based on airborne laser scanning (LIDAR). In contrast to traditional national park cartography, the multi-publishing framework sets new challenges for the map design. The paper summarizes the design process and gives examples of the in-house developed map design for so-called Topographic, Relief, Forest, Orthophoto and Winter maps. It concludes by discussing the design challenges of the multi-publishing framework.Ce papier décrit le processus de conception de cartes du projet MenoMaps dont les objectifs sont de 1/ créer de nouveaux types de cartes pour permettent les activités de loisirs en extérieur et 2/ de poursuivre des recherches sur l’utilisation de publications multiple dans un contexte cartographique. L’idée sous-jacente au service de publication multiple est que le service soit capable de produire différents types de cartes à travers différents canaux de diffusion, à différentes échelles, selon un design différent et ce à partir d’un noyau de données unique. Ce noyau de données est basé sur l’intégration de sources de données dont les cartes et bases de données du National Land Survey de Finlande, ainsi que les données environnementales du Parc National Nuukio de l’Institut de Géodésie de Finlande, en particulier des ortho-photographies à haute résolution et un modèle numérique de terrain basé sur des relevés LIDAR. En comparaison avec la cartographie traditionnelle des parcs nationaux, la structure de publication multiple apporte des nouveaux challenges dans la conception cartographique. Le papier résume le processus de conception et donne des exemples de conception de cartes dites topographiques, de relief, des Forets, Ortho et d’Hivers. Nous concluons en exposant les challenges de la conception dans la cadre d’une structure de publication multiple.

The Kyoto Protocol and the Private Forest Policy of Local Governments in Japan

National government policies on preventing global warming are becoming increasingly important in Japan, especially since the Kyoto Protocol became effective in 2005, and the first commitment period began in 2008. The Forestry Agency has combined policies promoting domestic forestry with those to prevent global warming and has developed a 10-year action plan. However, the forest resource database and related statistics represent serious problems in the forest management system in Japan and in the administrative work of the prefectural governments that manage the database. The database contains much incorrect data, which is difficult to correct because of insufficient budget and staff. The budget problem has seriously affected the entire administrative section of the Forestry Agency since the 1990s. Environmental taxes related to forests have recently been introduced in many prefectures, although the total revenue generated is small. The basic problem with the database is that the National Land Survey is incomplete and, consequently, the forest land size information in the database is unreliable. Furthermore, because prefectural governments are not required to report statistics on timber harvests, the cutting volume in each municipality is uncertain. Considering this situation, it may be difficult for the private forest sector to contribute greatly to the Kyoto Protocol without changes in the forest management system by both national and prefectural governments.

Development of the providing and management system for the national land survey information

To support the better utilization of the information arranged through the national land surveys (e.g., termed the Land Classification Survey, the Water Survey, etc. as the public works), the providing and management system of those national land survey information has been developed, which is operated under the network environment. To design the data set structure, the following three divisions on the information are newly defined: 1) Prescribed information, 2) Common information, and 3) Related information. The Data Set Management System (termed DSMS), that contributes to manage the data sets in the web-site by linking the index-information in the database-site, is constructed so that we can operate and manage the data sets efficiently. The developed system in this study actualizes the unitary-management of the data sets with respect to the administrative district, as well as the easy operation to refer the information under the network environment.

An optimum way to determine a precise gravimetric geoid model based on the least-squares modification of Stokes’ formula — A case study of Sweden

The modification of Stokes’ formula allows the user to compensate the lack of a global coverage of gravity data by a combination of terrestrial gravity and a global geopotential model. The minimization of the errors of truncation gravity data and potential coefficients could be treated in a least-squares sense as is the basic ingredient in the Royal Institute of Technology (KTH) approach as proposed by Sjöberg in 1984. This article presents the results from a joint project between KTH and the National Land Survey of Sweden, whose main purpose is to evaluate the KTH approach numerically and to compute a gravimetric geoid model for Sweden. The new geoid model (KTH06) was computed based on the least-squares modification of Stokes’ formula, the GRACE global geopotential model, a high-resolution digital terrain model and the NKG gravity anomaly database. The KTH06 was fitted to 1162 GPS/levelling points by a 7-parameter transformation, yielding an all-over fit of 19 mm and 0.17 ppm. The fit is even smaller than the estimated internal accuracy for the geoid model (28 mm). If we assume that the accuracy of the GPS and levelling heights are 10 mm and 5 mm, respectively, it follows that the accuracy of the expected gravimetric geoid heights are of the order of 11 mm. Also, we found a significant expected difference between the KTH06 and NKG2004 models in rough topographic areas (up to 36 cm). As the major ground data and global geopotential model were almost same in the two models, we believe that there are different reasons that come into play for interpreting the discrepancies between them, as the method for eliminating outliers from the gravity database, the interpolated denser gravity observations using the high-resolution digital elevation model before Stokes’ integration, the potential of the LSM kernel, which matches the errors of the terrestrial gravity data, GGM and the truncation error in an optimum way, and the effect of applying more precise correction terms in the KTH approach compared to the remove-compute-restore method. It is concluded that the least-squares modification method with additive corrections is a very promising alternative for geoid computation.

Remotely sensed estimation of cropland in China: a comparison of the maps derived from four global land cover datasets

the University of Maryland Dataset (UMD), the International Geosphere-Biosphere Programme Data and Information System Cover (IGBP-DISCover), the Moderate Resolution Imaging Spectrometer (MODIS) dataset, and the Global Land Cover 2000 (GLC2000). Although produced primarily for global applications, these global land cover datasets are often used for national or regional applications. The objective of this study was to examine the similarities and differences between these datasets in mapping Chinese cropland and to highlight their strengths and weaknesses when used at the national and regional scales. First, the total areas (in ha) of the cropland mapped by the four datasets were compared at the Chinese national, regional, and provincial levels. Second, we performed a pixel-by-pixel comparison of the spatial locations of cropland mapped by the four datasets. These datasets were then separately compared with the Chinese 1996 National Land Survey Dataset (NLSD-1996) to assess their accuracy in cropland mapping. The results show that, despite some agreement, there are discrepancies between the datasets, and the type and extent varies between regions. There are many reasons for the discrepancies, the main ones being the diverse land cover classification schemes, coarse spatial resolution, per-pixel classification approach, and landscape heterogeneity.

Creating a digital treeless peatland map using satellite image interpretation

In the satellite image-based estimation and classification of forest variables in Finland peatlands are usually processed separately from mineral soil forests, to improve the accuracy of the results. The division into peatlands and mineral soil forests is based on a mask provided by the National Land Survey. It would be advantageous, however, to update the mask with the satellite imagery used for estimating forest variables. The aim here was to compare methods for treeless peatland detection on a Landsat ETM+ satellite image. The area concerned was located within the southern aapa mire zone in Finland. The classification methods tested included sequential maximum a posteriori (SMAP), supervised maximum likelihood (ML) and unsupervised ML with Iso Cluster-based signatures. The unsupervised Iso Cluster ML method performed poorly, while the overall accuracies of SMAP and supervised ML were better and quite similar (88–94% and 89–90% on forestry land, respectively). SMAP produced more usable maps, by forming compact and unspeckled treeless peatland regions. The existing peatland mask was slightly more accurate than SMAP and ML, although it performed less well in the treeless peatland class. The updating of the existing mask by combining it with the best classification result did not succeed. The main conclusion is that a peatland mask can be based on Landsat TM classification, but in areas where a good topographic mask exists the latter is more useful, and cannot easily be updated with help of satellite image data.

Tree species discrimination using Z/I DMC imagery and template matching of single trees

Early results from automatic tree species discrimination, using the Z/I DMC digital aerial photographic camera are reported. The position of single trees is identified using template matching techniques and spectral data are extracted from the sunlit part of each detected tree crown. The imagery was acquired in mid-October 2003 for a test site in western Sweden. A discriminant analysis based on canopy colour yielded 88.7% overall accuracy when discriminating between Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and deciduous trees. The promising results are of great practical interest since the Swedish National Land Survey has recently acquired a Z/I DMC camera.

OBSERVATIONS OF L-AND C-BAND BACKSCATTER AND A SEMI-EMPIRICAL BACKSCATTERING MODEL APPROACH FROM A FOREST-SNOW-GROUND SYSTEM

Observations of Land C-band backscatter from snow cover are presented at all polarizations. Airborne passive-microwave data was collected in Northern Finland during EMAC’95 (European Multi-sensor Airborne Campaign-95). The measurements cover the 6.8–18.7 GHz frequency range with both vertical and horizontal polarizations. The empirical SAR data were acquired by EMISAR of Technical University of Denmark over the city of Oulu in Northern Finland during EMAC’95. Airborne measurements were conducted on 22–23 March, and on 2–3 May 1995. The land-use map of the test sites was obtained from the National Land Survey of Finland. This study combines the semi-empirical and empirical models that were developed. Applicability of the forest transmissivity formulas developed by using the different data sets of passive and active sensors is shown. Because of the effect of dry snow at C-band is more visible than at L-band. A C-band semi-empirical backscattering model is developed for the forest-snow-ground system.

Testing the Use of a Land Cover Map for Habitat Ranking in Boreal Forests

Habitat loss and modification is one of the major threats to biodiversity and the preservation of conservation values. We use the term ''conservation value'' to mean the benefit of nature or habitats for species. The importance of identifying and preserving conservation values has increased with the decline in biodiversity and the adoption of more stringent environmental legislation. In this study, conservation values were considered in the context of land-use planning and the rapidly increasing demand for more accurate methods of predicting and identifying these values. We used a k-nearest neighbor interpreted satellite (Landsat TM) image classified in 61 classes to assess sites with potential conservation values at the regional and landscape planning scale. Classification was made at the National Land Survey of Finland for main tree species, timber volume, land-use type, and soil on the basis of spectral reflectance in satellite image together with broad numerical reference data. We used the number and rarity of vascular plant species observed in the field as indicators for potential conservation values. We assumed that significant differences in the species richness, rarity, or composition of flora among the classes interpreted in the satellite image would also mean a difference in conservation values among these classes. We found significant differences in species richness among the original satellite image classes. Many of the classes examined could be distinguished by the number of plant species. Species composition also differed correspondingly. Rare species were most abundant in old spruce forests (>200 m3/ha), raising the position of such forests in the ranking of categories according to conservation values. The original satellite image classification was correct for 70% of the sites studied. We concluded that interpreted satellite data can serve as a useful source for evaluating habitat categories on the basis of plant species richness and rarity. Recategorization of original satellite image classification into such new conservation value categories is challenging because of the variation in species composition among the new categories. However, it does not represent a major problem for the purposes of early-stage land-use planning. Benefits of interpreted satellite image recategorization as a rapid conservation value assessment tool for land-use planners would be great.

Finnish landscape studies – a mixture of traditions and recent trends in the analysis of nature-human interactions

Finnish landscape studies have long methodological traditions stretching back to the early 20th century. These are reflected in present-day landscape research, which is practised within various university disciplines and research institutions, representing both the sciences and the humanities and also applied fields. We have categorised Finnish landscape studies under four main themes: (1) theoretical and methodological, (2) ecological, (3) social and cultural, and (4) applied. The focus of Finnish landscape research has been on both physical landscape characteristics and their spatial and temporal interactions, and also on the diverse social context of landscapes. Finnish landscapes have been mapped and delineated on several occasions, the latest landscape map being based on a publication by the National Land Survey and the Geographical Society of Finland dating from 1994. This classification recognizes landscape areas defined hierarchically on three spatial levels using the proportions and spatial configurations of ground, water, vegetation and man-made forms. The future of Finnish landscape studies is tied to whether knowledge about nature-human interactions on the visible surface of the earth will be able to overcome the fragmentation brought about by specialization. What is needed is a common world of concepts, a new way of thinking. This will call for transdisciplinary concepts, intertraditional points of view, in which quantitative and explicatory methods are complemented by qualitative approaches and methods which emphasize understanding, meanings and symbols.

INCREASED CANCER INCIDENCE IN NORTH SWEDEN-AN EARLY PROMOTING EFFECT CAUSED BY THE CHERNOBYL ACCIDENT

Introduction In Sweden the ground gamma radiation, due to uranium containing granite, contribute to the population's total radiation dose. After the Chemobyl nuclear power plant accident in 1986 as much as five percent of the released caesium-137 was deposited in Sweden, especially in the Northern part of the country. Our hypothesis was that this radiation caused increased cancer incidence, after adjustment by ground gamma radiation exposure. Methods The study base included the population of eight counties with the highest fallout after the Chernobyl accident, but also with unaffected areas in these counties serving as the reference. Each person 0–60 years of age living in the same parish at 31 December 1985 and 31 December 1987 were included in a cohort. With the coordinate of each person's dwelling from the National Land Survey of Sweden a total of 1 137 106 individuals could be given 1) ground gamma radiation exposure from the digital map of the Swedish Geological Agency and 2) caesium-137 exposure from a similar map created by Swedish Radiation Protection Institute. Accuracy of the dwelling coordinate was 100 metres and for the radiation exposures 200 metres as done by aeroplane measurements. Three time periods were analysed 1988–1991, 1992–1995 and 1988–1999. Results Population density, lung cancer incidence 1988–1999 and total cancer incidence 1986–1987 was risk factors for total cancer outcome in 1988–1999. Age adjusted ERR per 100 nGy/h for ground gamma radiation and total cancer incidence did not show any significant dose response measured, either in each three years time intervals or in the total period of 1988–1999. For caesium the ERR per 100 nGy/h (adjusted by population density, lung cancer incidence, total cancer incidence 1986–1987 and ground gamma radiation) was significant in 1988–1991 followed by a decline in risk 1992–1995 and then a slight but not complete return in risk. The ERR of 0.042 (95% CL 0.001;0.084) per 100 nGy/h for caesium exposure 1988–1999 is therefore dependent on the first three years increase, and to less extent by the following six years. Conclusion We have found an early effect of the Chernobyl fallout in Northern Sweden. However, even in the ERR of 0.101 per 100 nGy/h is relatively low in 1988–1991, it is stable in a stepwise regression, and therefore indicating a true effect. An interpretation of our results could be that the sudden exposure of ionizing radiation from Chernobyl might have acted as a late stage general promotor for cancer. Such an early effect can hitherto been overlooked in previous studies.

MapSite - an Internet map service of the National Land Survey of Finland gets dressed up with modern technology

MapSite of the National Land Survey of Finland was the first national Internet map service in Europe. It was launched in September 1996. Since then the service has been a huge success. Until now it has almost 300,000 users in all, the number of paying customers is over 2,000. In the spring of 2001 National Land Survey (NLS) started a project to produce a new Internet map service to replace the old MapSite. The developing project is divided in three phases. In the first phase services of paying customers are renewed. Free of charge map browsing service is being modernised in the second phase. Totally new services may be produced in the third phase.

Wetland classification for Swedish CORINE Land Cover adopting a semi-automatic interactive approach

In a collaboration between the Swedish Space Corporation and the National Land Survey of Sweden, work has been carried out to develop a satellite-data-based method for mapping wetlands for the Swedish CORINE Land Cover database. The aim was two-fold: (1) develop a method for mapping the wetlands in five classes, namely "inland marshes", "wet mires", "other mires", "exploited peatlands", and "salt marshes", with a minimum mapping unit of 1 ha; and (2) investigate if the classes "wet mires" and "other mires" could be obtained more reliably from satellite data than directly from 1 : 50 000 scale topographic maps. Data sources used in the project included geo-referenced Landsat thematic mapper (TM) images, digital topographic map data, digital vegetation data, and colour infrared aerial photographs. The development work included analysis of spectral signature characteristics, classification tests, method definition, method verification, pilot production, and accuracy assessment. The method developed to obtain the five wetland classes is a combination method. The classes inland marshes, salt marshes, and exploited peatlands are mapped using geographical information system (GIS) operations, combining information from the topographic maps, and visual interpretation of Landsat TM data. For the classes wet mires and other mires, a stepwise semi-automatic approach was adopted, where level slicing in ratios or in single Landsat TM bands is used to produce the classes. The evaluation showed high accuracy for all five classes, with overall accuracies ranging from 90% to 100%. It was also concluded that the semi-automatic interactive approach used to produce wet mires and other mires gave the same high accuracy as the topographic map, or a better result than the map for areas in northern Sweden where the representation of wet mires on the map is not as good. The method described is used for production of the wetland classes for the Swedish CORINE Land Cover.

Development of the providing and management system for the national land survey information

Development of the providing and management system for the national land survey information

GIS analysis of change in an agriculture landscape in Central Finland

Changes in landscape over a period of 50 years were analysed in a rural area of 324 ha in Central Finland. The data were digitized from aerial photographs of the National Land Survey taken in 1944, 1959, 1979 and 1991, and analysed with the IDRISI™ geographic information system (GIS). The average proportion of land in agricultural use in the sample area was 17.4%. The arable area declined from the maximum of 62.3 ha (1959) to 47.6 ha. The total length of linear landscape elements, predominantly ditch bank habitats, halved, from 876 m/ha of field (1944) to 449 m/ha by the end of the period. The average rate of loss of field boundary habitat was 9.1 m/ha/ year. At the same time, the Shannon-Weaver index of diversity of agricultural landscape elements dropped from 0.37 to 0.24. The number of field parcels declined by 29%, and the mean parcel size increased by 45%, from 1.2 ha to 1.7 ha. The index value of the fractal dimension measuring the complexity of parcel shapes also fell, from 1.88 (1959) to 1.86 (1991). The change in spatial structure reflects the intensification of farming in Finland. Biodiversity at ecosystem level has clearly declined. However, the implications for the agroecosystem and its sustainability are still unknown.