National Land Survey Research Articles

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.

State of national land survey and large-scale mapping

There is still a dearth of appropriate and adequate land survey and large-scale mapping coverage in many countries to facilitate more effective land-related planning, development and management. This situation, in relative terms, applies to both developed and developing countries. Fortuitously, technology is now available and accessible to expand land surveys and the production of large-scale maps at the scales required to support planning and sustainable land development and management. What is now required is official public policy recognition, the attribution of a higher level of priority to this issue, and the allocation of adequate resources to implement an expanded production programme of large-scale maps of cities, towns and villages to facilitate more appropriate settlements and other related land development planning.

EDI based geographic information service

EDI (Electronic Data Interchange) based geographic information service is a general client/server approach enabling automatic information service to end user applications. It is based on international standards and can be implemented with general EDI software tools. All important geographic data resources will be available for the applications which are able to send an electronic order through a data network and in real-time receive the response data sent by the data supplier's server system. EDI based information service is designed, piloted, standardised and implemented in Finland. Many of the national data suppliers are active and the service already covers ten databases. The Geographic Information Centre at the National Land Survey is maintaining a geographic data directory system and supporting the implementation of services and end user applications by consulting and by developing software supporting the standards.

Rock block map analysis of southern Sweden

Abstract The fracturing of the crust in southern Sweden has been investigated by means of topographical data, presented by the National Land Survey as the Relief Map of Sweden. Rock blocks of 3 different orders are presented in maps. On the basis of these maps, four regions have been distinguished, based on the character of the fracture pattern; southeastern Sweden with fairly regular pseudo-orthogonal patterns, southwestern Sweden with lensoidal patterns, the central belt with a penetrative north-southerly trend, and Skåne in the Fennoscandian Border Zone. Southeastern Sweden is dominated by a N10W grain, while the other regions, west of a line c. 30 km east of Lake Vättern, have a N20E grain. Rock block boundaries have been separated into 6 sets, according to their orientation. All sets show an arrangement of fractures into megalenses. The rate of the relative uplift of Fennoscandia is symmetric across southern Sweden, although the seismi-city is mainly confined to the western part. This implies that the differential movements in southeastern Sweden are aseismic, suggesting that the fracture pattern can accommodate applied strain. In southwestern Sweden, however, slip cannot occur along displaced curved fractures. The occurrence here of a late pseudo-orthogonal pattern in seismic areas, implies that new fractures form, if the crust cannot deform along existing fractures.

Experience with the ULISS-30 inertial survey system for local geodetic and cadastral network control

The capability of the recently developed SAGEM ULISS-30 inertial survey system for performing local surveys at high accuracies have been tested in a field campaign carried out November 1989 on the island of Fyn, Denmark, in cooperation with the Swedish National Land Survey. In the test a number of lines between existing national geodetic control points were surveyed, along with points in the less reliably determined cadastral network, forming an irregular network pattern of 10–15 km extent. The survey involved frequent offset measurements (up to 50–100 m) with an ISS-integrated total station. The profile geometries were not particularly suited for inertial surveys, with narrow and rather winding roads, necessitating frequent vehicle turns. In addition to the pure inertial surveys a kinematic GPS/inertial test was also carried out, using a pair of Ashtech L-XII receivers. The inertial survey results, analyzed with a smoothing algoritm utilizing common points on forward/backward runs, indicate that 5-cm accuracies are possible on reasonably straight profiles of 5 km length, corresponding to a 10 ppm “best-case” accuracy for double-run traverses. On longer, more winding traverses error levels of 10–20 cm are typical. To handle the inertial data optimally, proper network adjustments are required. A discussion of suitable adjustment models of both conventional and collocation type is included in the paper.

Recent Tendency of Geography in Japan

As premises for main topics of inquiries, a brief review is made of the status of the wartime geography in Japan which should seem to have a direct bearing on the later development of this field. There, the oversea expeditions, war-time researches, and “Geopolitik” at their time, and their later influences are pointed out.Status of Geography since 1945 is elucidated according to the following headings.1) Various kinds of national land surveys in connection with the various land planning projects.2) Promotion of international intercourse.3) Establishment of departments of geography in universities and colleges throughout the country.4) Dispatch of oversea scientific investigation parties.5) Propulsion of joint studies by workers of various fields of geography, and participation of geographers in various interdisciplinal studies.6) Problems waiting for future solution.