File README-2006.txt (UTF-8) 30.11.2021 MULTI-SOURCE NATIONAL FOREST INVENTORY (MS-NFI) RASTER MAPS OF 2006 =================================================================== 1. Terms of Use --------------- The Natural Resources Institute Finland (Luke) owns the copyright, data protection, and other immaterial rights to this product. The Topographic Database from the National Land Survey has been utilized when making the product. This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. When using the material, the owner of the rights to the material must be given as "©Natural Resources Institute Finland, 2011" and the name of the material must be given as "The Multi-source National Forest Inventory Raster Maps of 2006". The description of the method is in the references at the end of this file. A scientific citation practice shall be used in research use. 2. The Files ------------ The raster maps include three themes (described later). For delivery, each theme is divided into subsets according to the Finnish TM35 division of maps from the National Land Survey (URL http://www.nls.fi/). For simplicity, the sheets K2 and L2 (Ahvenanmaa) are combined as well as the sheets V3 and W3 (Lapland). The raster files are in GEOTIFF format. The map coordinate system is ETRS-TM35FIN. The pixel size in the map coordinate system is 20 m by 20 m. These themes have been reprojected from the original themes in the Finnish YKJ coordinate system with 25 m by 25 m pixel size. The results are in 8-bit numbers. The unit of each theme is given later. The values 254 and 255 has been reserved for the following purposes: 254 pixel where result should have been computed but it was not possible because of, e.g., clouds 255 pixel that is outside forest land, poorly productive land, or unproductive land, or is not in Finland 3. Contact and more information ------------------------------- More information about the Finnish multi-source national forest inventory is given at https://www.luke.fi/en/natural-resources/forest/forest-resources-and-forest-planning/forest-resource-maps-and-municipal-statistics/ The queries about the products are asked to be sent to the email address mvmi@luke.fi. 4. The Material --------------- 4.1 General information The Finnish Forest Research Institute (Metla) developed a method called multi-source national forest inventory (MS-NFI). The first operative results were calculated in 1990. The first country level estimates correspond to years 1990-1994. Small area forest resource estimates, in here municipality level estimates, and estimates of variables in map form are calculated using field data from the Finnish national forest inventory, satellite images and other digital georeferenced data, such as topographic database of the National Land Survey of Finland. Nine sets of estimates have been produced for the most part of the country until now and eight sets for Lapland. Three themes (mean height, canopy cover, and canopy cover for deciduous trees) were produced outside the normal MS-NFI work for production of the CORINE2006 data set. These themes were also the first INSPIRE themes from MS-NFI. The products cover the combined land categories forest land, poorly productive forest land and unproductive land. The other land categories, as well as water bodies, have been delineated out using the elements of topographic database of the Land Survey of Finland. This classification is independent of the estimated themes. 4.2 Construction of the theme maps Field data from about 45 000 NFI sample plots from years 2004-2007 (NFI10) (2003, NFI9 in northernmost Finland) were used. The satellite images used included 57 IRS images and 41 Spot images fomr years 2005-2007. Regeneration cuttings on the field plots were assessed using satellite images and, in some cases, with aerial photographs. The plots were removed where the cuts status in field data clearly did not match the image. The map form estimates were made using the improved k-Nearest Neighbour method (ik-NN method). The value of five for k was used most frequently. The weights of the features in the ik-NN method are sought using an optimization method based on genetic algorithm. Coarse scale estimates of forest variables were used as the supplementary data. The volumes by tree species groups were selected as the variables. The purpose is to direct the selection of the neighbours, on the average, to forests similar to the target pixel (see the references below). The estimation was made separately for mineral soils, mires and open bogs and fens. The stratification of both the satellite image and the field plots were made using the topographic map data of Land Survey Finland. 4.3 The themes The mean height of the trees on a forest stand is the height of the basal area median tree for the development classes young thinning stand or more mature stands. It is about the same as the basal area weighted average height. For seedling stands, the mean height is the average height of the dominant and co-dominant seedlings. The mean height is assessed in the field in the classes of 1 dm. In the result theme, the mean height has been divided by two, meaning that the unit is 2 dm. The canopy cover of trees is the vertical projection area on the horizontal plane of the canopies of the individual trees on a field plot (without double counting the overlapping canopies). In NFI10, it was assessed in the field as a shares (0-99%) on a fixed radius plot. In North Lapland in NFI9, the canopy cover was assessed in three categories if the plot was either on forest land, poorly productive forest land or unproductive land. A regression model was constructed to estimate the cover in the classes of one percent. The canopy cover proportion of broad-leaved trees is derived from the total cover using the basal area. However, in the seedling stands, the canopy cover of broad-leaved trees is assessed using the shares of the stem numbers. 4.4 References More information about the methods and the accuracies are given in the publications, e.g.: Törmä, M., Haakana, M., Hatunen, S., Härmä, P., Kallio, M., Katila, M., Kiiski, T., Mäkisara, K., Peräsaari, J., Piepponen, H., Repo, R., Teiniranta, R. ja Tomppo, E., 2008. Finnish Corine 2006-project: Determining Changes in Land Cover in Finland between 2000 and 2006. Remote Sensing for Environment Monitoring, GIS Applications and Geology VIII, Proceedings of SPIE vol. 7110. Tomppo, E., Haakana, M., Katila, M. & Peräsaari, J. 2008. Multi-source national forest inventory - Methods and applications. Managing Forest Ecosystems 18. Springer. 374 p. ISBN 978-1-4020-8712-7 Tomppo, E. & Halme, M. 2004. Using coarse scale forest variables as ancillary information and weighting of variables in k-NN estimation: a genetic algorithm approach. Remote Sensing of Environment 92: 1-20. 5. The list of the themes and the file names File name Theme keskipituus_ Stand mean height (2 dm) latvuspeitto_ Canopy cover (%) lehtip_latvuspeitto_ Canopy cover of broad-leaved trees (%)