Fig 3 - uploaded by Heikki Salmirinne
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Airborne magnetic map of the Otanmäki area based on GTK's airborne surveys in 1979. The location of the Metsämalmi UAS test area on the NE edge of the Otanmäki gabbroic intrusion is indicated by a blue polygon (Basemaps © National Land Survey of Finland).
Source publication
In September 2018, a field campaign was performed to test the
newly designed UAS systems at the Otanmäki Fe–Ti–V deposit in central Finland. In this
report, the acquisition and processing of UAS-based magnetic, multi- and hyperspectral
datasets in Otanmäki are described.
Contexts in source publication
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... survey included magnetic, electromagnetic and radiometric measurements. The sub-section of the airborne magnetic map around Otanmäki is presented in Figure 3. ...
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... is mainly due to its higher sample rate and its possibilities to better filter out high-frequency noise. To investigate the differences between the two flights, Figures 33-35 show the misfit in a) ELMcomputed data at the altitude of 35 m, b) corrected data and c) computed data at the original data locations between the two flights. As expected, the misfit is smallest for the ELM- ...
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... this section, we discuss the quality of the result- (Fig. 22) and from the regional airborne data (Fig. ...
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... magnetic signals associated with shallow anomalies. In the future, a better way to remove such noise while keeping more of the high-frequency signal content could be to apply the ELM from Radai Oy (see sections 3.1.1.4 and 5). Another option could be to add a Fig. 48. TMI map for the copter flight with a height level of 15 m a.g.l. In contrast to Fig. 3.39, a Gaussian filter with std. dev. = 50 m was applied in addition to the common processing to mitigate the remaining artefacts. The first vertical derivative of the TMI from the same ...
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... the focus of the study was the investigation of soil and rock surfaces, the in-scene vegetation was removed. For this purpose, the Normalized Difference Vegetation Index (NDVI; Tucker 1979) was calculated for both the multi-and hyperspectral mosaics (see Fig. 53) and a binary mask was created by using an NDVI threshold of >0.3. This binary mask was applied to clip pixels with a high vegetation content from the eastern part of the HSI mosaic. Note that the vegetation indices can also be a proxy for specific mineral abundances or soil factors (e.g. Grebby et al. 2014). Furthermore, studies have ...
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... investigate how well magnetic and spectral characteristics coincide in detecting iron oxides, susceptibilities from a single susceptibility surface profile (profile 473; see Fig. 6) were compared with the band ratio values from the multispectral Sequoia survey, which indicate iron oxide mineral absorption (band 3/band 4). Figure 73 presents a map in which both the band ratio and the susceptibility measurements are plotted. Vegetation and lichen cover a significant part of the surface, which impedes the capability to detect minerals on the surface. ...
