Yhteistyökumppaneiden julkaisut: Recent submissions

Now showing items 1-20 of 13065
  • Matikainen, Leena; Pandzic, Milos; Li, Fashuai; Karila, Kirsi; Hyyppä, Juha; Litkey, Paula; Kukko, Antero; Lehtomäki, Matti; Karjalainen, Mika; Puttonen, Eetu (SPIE, 2019)
    Journal of Applied Remote Sensing
    The rapid development of remote sensing technologies pro-vides interesting possibilities for the further development of nationwide mapping procedures that are currently based mainly on passive aerial images. In particular, we assume that there is a large undiscovered potential in multitemporal airborne laser scanning (ALS) for topographic mapping. In this study, automated change detection from multitemporal multispectral ALS data was tested for the first time. The results showed that direct comparisons between height and intensity data from different dates reveal even small chang-es related to the development of a suburban area. A major challenge in future work is to link the changes with objects that are interesting in map production. In order to effectively utilize multisource remotely sensed data in mapping in the future, we also investigated the potential of satellite images and ground-based data to complement multispectral ALS. A method for continuous change monitoring from a time series of Sentinel-2 satellite images was developed and tested. Finally, a high-density point cloud was acquired with terres-trial mobile laser scanning and automatically classified into four classes. The results were compared with the ALS data, and the possible roles of the different data sources in a fu-ture map updating process were discussed.
  • Perheentupa, Viljami; Mäkinen, Ville; Oksanen, Juha (Copernicus Publications, 2019)
    The Abstracts of the International Cartographic Association
    Glacial isostatic adjustment (GIA) is an ongoing phenomenon that characterizes the landscape of the High Coast (63°04'N, 18°22'E, Sweden) / Kvarken archipelago (63°16'N, 21°10'E, Finland) UNESCO World Heritage site. GIA occurs as the Earth’s crust that was depressed by the continental ice sheet during the last glacial period is slowly rebounding towards isostatic equilibrium. The maximum rate of land uplift in the area is more than eight millimetres per year, which – along with the very different topographical reliefs of the opposite coasts – makes the region an excellent study area for land uplift as a phenomenon. As there is a marine area between the coasts, shore displacement is an essential part of the phenomenon in the study area. The cartographic representation of GIA and shore displacement has classically relied on static maps representing isobases of the uplift rates and of ancient shorelines. However, to dynamically visualize and communicate the continuity and the nature of the phenomena, an animated map is required. To create a visually balanced, seamless animation, we need to create high-resolution image frames that represent digital elevation models (DEMs) together with extracted shorelines of different moments of time. To create these frames, we developed a mathematical model to transform the DEM in a given time for the past ~9300 years. We used the most recent LiDAR-derived DEMs of Finland and Sweden, and a bathymetric model of the Gulf of Bothnia as our initial data, along with a land uplift rate surface derived from geophysical measurements. We compared the current uplift rates with the shoreline observations of the ancient Baltic Sea stages, Litorina Sea and Ancylus Lake, and created a linear model between the elevations of the shorelines and the present-day uplift rates, as there was a near-linear correlation in both cases. Based on the current uplift rates and the elevations and the dating of the ancient shorelines, we derived an exponential model to describe the non-linear correlation between the elapsed time and the occurred land uplift. Near the present time, we adapted the formula proposed by Ekman (2001) to make the model more robust closer to the present day. We assumed that although the uplift rate varies in time, the spatial relation of uplift rates remains the same. Furthermore, as the land uplift is an exponentially decelerating phenomenon occurring with a significantly lower annual rate than shortly after the de-glaciation (Eronen et al. 2001, Nordman et al. 2015), and with most of the total uplift already having occurred (Ekman 1991), we assumed a constant rate of uplift from the present day to the near geological future. We did not consider potential sea level changes caused by human-driven climate change in the predictions, as the geological time scale vastly exceeds the time range of the climate models. Neither did we take into account the historical transgression phases, as they did not appear dominating in the area. The elevation and bathymetry data were harmonized and resampled into 4K (3840 x 2160) pixel dimensions to utilize the best commercially available screen resolutions and to avoid unnecessary sub-pixel level computations. This resulted in a spatial pixel size of about 200 metres. The initial spatial resolution of the DEMs of Finland and Sweden was 2 metres and 1 metre, respectively, while the bathymetric data had a spatial pixel size of 400 metres. This, along with the fact that the bathymetric data was partly modelled and inaccurate near the coastlines, meant that it had to be oversampled to generate plausible coastal bathymetry and to allow any future estimations of shore displacement. All the datasets were resampled to EPSG:3857 Pseudo-Mercator projection to facilitate any future use in web map applications. As the visualized area is only about 430 kilometres in the north-south direction, the use of this projection did not introduce cartographic issues. The rendered frames required by the animation were produced with a programmatic conversion of raster files to RGBimages. The visualization of shore displacement was implemented by a discontinuity in elevation dependent colour scale at sea level. The bathymetry was visualized with a continuous colour scale in shades of blue until the elevation of zero metres. Elevations above zero were visualized with a colour scale starting from green to create an impression of a discrete shoreline (Figure 1). Figure 1. Examples of individual frames for the land uplift animation. Litorina stage 7300 BP (a), 3000 BP (b), current stage (c), and 1000 years after present (d). The imprecision of the predicted shoreline placement compared to the past reconstructions can be observed in the last frame. The whole process from computing the DEMs to rendering the frames was implemented in Python, without the need for traditional GUI operated GIS or image processing software. The raster data was read and processed with GDAL and NumPy libraries, and the visualization was carried out using Matplotlib and Python Imaging Library. Each DEM was given the same elevation based colour scale and an individually created hillshading that was blended with the image by multiplication. The whole process was carried out as an open source solution. The interval between the calculated frames was set to five years as, particularly at the Swedish coast, the shore displacement can appear abrupt with a longer time interval. The frame duration was set to 0.05 seconds, which means a 100-second duration for an animation of 10 000 years. The resulting DEM reconstructions show good agreement with comparable data, such as the Litorina reconstructions by the Geological Survey of Finland (GTK). Also, the mathematical model appears to be in line with previous reconstructions conducted in the area (e.g. Nordman et al. 2015). So far, any continuous series of paleogeographic DEM reconstructions comparable to ours has not been published for this area. The animation provides an understandable way of perceiving the continuous but decelerating nature of the land uplift phenomenon and also highlights the differences in the post-glacial history of Finnish and Swedish coasts. To further improve the visualization, we must consider the removal of post-glacially developed features in the present day DEM, e.g. the various rivers that can both cause bias in the shore displacement and uplift estimations and appear visually distractive. In the very early frames of the animation, the retracting ice sheet must also be present. Also, a balanced addition of other cartographic elements, such as present-day hydrography and place names, can further improve the overall presentation.
  • Liski, Matti; Nokso-Koivisto, Oskari; Lackbergh, Jenna (Kela, 2019)
    Kuntoutusta kehittämässä
    Kela hankkii vuosittain vaativan lääkinnällisen ja harkinnanvaraisen kuntoutuksen kursseja sekä moniammatillista yksilökuntoutusta 60 miljoonalla eurolla 27 000 asiakkaalle. Palveluntuottajia on 150. Onnistuessaan hankinta johtaa tasapainoisesti hankkijan asettamien tavoitteiden toteutumiseen. Hankintatavan valinta sekä hankintamekanismin yksityiskohdat vaikuttavat hankinnan onnistumiseen. Raportissa tarkastellaan vaativan lääkinnällisen ja harkinnanvaraisen kuntoutuksen kuntoutuskurssien sekä moniammatillisen yksilökuntoutuksen hankintaa taloudellisesta näkökulmasta. Ensisijaisesti raportissa on keskitytty Kelan kohtaaman hankintaongelman periaatteelliseen tarkasteluun. Raportti havainnollistaa aiempien hankintojen ominaisuuksia aineistosta tehtyjen kuvaajien avulla. Kansaneläkelaitos pyrkii siirtymään hankinnassa rekisteröitymismenettelyyn, jossa laadullisen seulan läpäisseet palveluntuottajat voisivat rekisteröityä palveluntuottajiksi ilman nykyisen kaltaista hankintamenettelyä. Yksi raportin tavoitteista on rekisteröitymismenettelyn uhkien ja mahdollisuuksien selvittäminen. Selvityksessä on tunnistettu nykymenettelystä kolme periaatteellista ongelmaa. Ensimmäinen ongelma liittyy hankintatavan joissakin tapauksissa aiheuttamaan kannusteeseen tarjota kustannukset selvästi ylittävää hintaa. Toinen ongelma on samanaikaiset ja toisiinsa liittymättömät hankinnat, jotka altistavat palveluntuottajat kohtaamaan turhaa epävarmuutta. Epävarmuus nostaa palveluntuottajien kustannuksia ja siten myös hankinnan kustannuksia. Kolmas ongelma liittyy kilpailun määrään. Palveluntuottajilla on vähän kannusteita tarjota kustannuksia lähellä olevaa hintaa, kun kaikki tarjoajat joudutaan hyväksymään riittävän kapasiteetin hankkimiseksi. Raportissa todetaan, että yksinkertaisimmillaan tavoitteisiin pääsemiseksi hankintatapaa olisi kehitettävä nykyisen hankintatavan pohjalta. Raportissa esitetään, että hankintatapaan tehtäisiin sellaisia muutoksia, jotka saisivat palveluntuottajat kilpailemaan tasapainoisesti laadulla ja hinnalla sekä helpottaisivat alalle tuloa. Tärkeää olisi myös vähentää palveluntuottajien kokemaa turhaa epävarmuutta.
  • Venäläinen, Ari; Ruosteenoja, Kimmo; Lehtonen, Ilari (2019)
    Raportteja – Rapporter – Reports 2019:3
    This report deals with projected climatic changes in four areas of operation of the UPM-Kymmene company: Finland, southern Germany, Uruguay and eastern China. The implications of the projected changes for forestry, including forest growth and productivity and possible climate change induced disturbances, are discussed as well. Climate projections have been derived from the output of 28 global climate models. Analyses focus on the RCP4.5 greenhouse gas scenario that represents an alternative of moderately large emissions. Mainly, projections calculated for the period 2040–2069 (relative to 1971–2000) have been examined. All the models analyzed simulate higher temperatures for the future. However, the degree of warming varies quite a lot among the models. For many other climate variables, like precipitation and incident solar radiation, even the sign of the future change can be uncertain. Even so, in the regions examined mean precipitation is more likely to increase than decrease, except for southern Germany in summer and early autumn, Uruguay in Southern Hemisphere winter and spring and China in late autumn. Rising temperatures enhance evaporation and increase drought risks despite modest increases in precipitation. In some seasons, both the intense rainfall events and dry periods are projected to become more severe. In recent decades, forest resources have been increasing in Europe. Especially in Northern Europe, forests have benefitted from the warmer climate and increased CO2 concentration in the atmosphere. During the coming decades, this positive development may at least partly be cancelled due to potentially increasing disturbances for the forest growth. For example, drought, fire and insect pests may cause damage. The role of forests as a carbon sink is an important aspect in the context of climate change mitigation activities, and vivid discussion on the most beneficial and sustainable use of forest resources is foreseen to continue. If global climate policy proves to be successful, it is possible that future changes in climate will be weaker than those based on the RCP4.5 scenario discussed in this report. However, this requires rapid restrictions of the greenhouse gas emissions globally.
  • Susiluoto, Jouni (2019)
    Finnish Meteorological Institute Contributions 154
    Climate change is one of the most important, pressing, and furthest reaching global challenges that humanity faces in the 21st century. Already affecting daily lives of many directly and everyone indirectly, changes in climate are projected to have many catastrophic consequences. For this reason, researching climate and climate change is needed. Studying complex geoscientific phenomena such as climate change consists of a patchwork of challenging mathematical, statistical, and computational problems. To solve these problems, local and global process models and statistical models are combined with both small in situ observation data sets with only few observations, and equally well with enormous global remote sensing data products containing hundreds of millions of data points. This integration of models and data can be done in a Bayesian inverse modeling setting if the algorithms and computational methods used are chosen and implemented carefully. The methods used in the four publications on which this thesis is based range from high-dimensional Bayesian spatial statistical models and Markov chain Monte Carlo methods to time series modeling and point estimation via optimization. The particular geoscientific problems considered are: finding the spatio-temporal distribution of atmospheric carbon dioxide based on sparse remote sensing data, quantifying uncertainties in modeling methane emissions from boreal wetlands, analyzing and quantifying the effect of climate change on growing season in the boreal region, and using statistical methods to calibrate a terrestrial ecosystem model. In addition to analyzing these problems, the research and the results help to understand model performance and how modeling uncertainties in very large computational problems can be approached, also providing algorithm implementations on top of which future efforts may be built.