In this study, we investigated which types and categories of cultural remains that were most likely to be detected and classified correctly Continue reading
Earlier this year a study investigating the use of multispectral imagery in addition to measurements from airborne laser scanning (ALS) for tree species identification was published in Canadian Journal of Remote Sensing. Multispectral imagery from a medium-format digital frame camera acquired simultaneously with ALS data were utilized and compared with imagery from a large-format digital frame camera acquired on a separate flight mission from a higher altitude. The two acquisitions represent cost efficient methods for data collection of both three-dimensional and spectral information. The classification accuracy was assessed using 1520 segmented spruce, pine, and deciduous trees. Furthermore, ALS intensity was normalized using the range from sensor to the target (range normalization). In addition, a source of variation in intensity known as banding, is described together with a normalization procedure for diminishing this effect. The normalized intensity was better than using the raw intensity, but it did not improve the classification compared with using only ALS structural information, which provided overall classification accuracies of 74%–77%. The combined use of ALS and multispectral imagery from the medium-format imagery acquired simultaneously and the separate acquisition of large-format imagery provided overall accuracies of 87%–89% and 83%–85%, respectively. Simultaneous acquisition of ALS and medium-format digital imagery provides an efficient data acquisition strategy for tree species identification in forest inventory and will likely reduce data acquisition costs by 10%–20%.
Marius Hauglin presented a lecture on a predefined topic and defended his doctoral thesis on December 7, 2012. Continue reading
During the last 10 – 15 years there has been growing interest towards the use of forest biomass for energy purposes. Continue reading
In a recent study published in Remote Sensing of Environment two sampling and estimation strategies for regional forest inventory were investigated in detail and results were presented for various geographical scales. Continue reading
Alpine and arctic tree lines are expected to advance to higher altitudes and further north due to global warming. Changes in temperature, precipitation, and snow coverage will affect numerous ecosystems and their interaction and forest ecosystems are expected to be highly affected by increasing temperatures, particularly in boreal regions. Continue reading
Hans Ole Ørka presented a lecture on a predefined topic and defended his doctoral thesis on Friday 24, Juni 2011. Continue reading