Filter by collection

Current filters:

Current filters:

Refine By:

Search Results

Results 21-30 of 1521 (Search time: 0.002 seconds).
Item hits:
  • BB

  • Accuracy Analysis of Photogrammetric UAV Image Blocks: Influence of Onboard RTK-GNSS and Cross Flight Patterns

    • Authors: Gerke, M.;  Advisor: -;  Participants: - (2016)

  • Unmanned aerial vehicles (UAV) are increasingly used for topographic mapping. Despite the flexibility gained when using those devices, one has to invest more effort for ground control measurements compared to conventional photogrammetric airborne data acquisition, because positioning devices on UAVs are generally less accurate. Additionally, the limited quality of employed end-user cameras asks for self-calibration, which might cause some problems as well. A good distribution of ground control points (GCPs) is not only needed to solve for the absolute orientation of the image block in the desired coordinate frame, but also to mitigate block deformation effects which are resulting mainly from remaining systematic errors in the camera calibration. In this paper recent developments in ...
  • BB

  • Adjusting spectral indices for spectral response function differences of very high spatial resolution sensors simulated from field spectra

    • Authors: Cundil, Sharon L.;  Advisor: -;  Participants: - (2015)

  • The use of data from multiple sensors is often required to ensure data coverage and continuity, but differences in the spectral characteristics of sensors result in spectral index values being different. This study investigates spectral response function effects on 48 spectral indices for cultivated grasslands using simulated data of 10 very high spatial resolution sensors, convolved from field reflectance spectra of a grass covered dike (with varying vegetation condition). Index values for 48 indices were calculated for original narrow-band spectra and convolved data sets, and then compared. The indices Difference Vegetation Index (DVI), Global Environmental Monitoring Index (GEMI), Enhanced Vegetation Index (EVI), Modified Soil-Adjusted Vegetation Index (MSAVI2) and Soil-Adjusted ...
  • BB

  • Adapting Scotland’s forests to climate change using an action expiration chart

    • Authors: Petr, M.;  Advisor: -;  Participants: - (2015)

  • The inherent uncertainty of climate change impacts is one of the main challenges for adaptation in environmental management. The lack of knowledge about climate impacts on ecosystem services at high spatial and temporal resolution limits when and what adaptation measures should be taken. We addressed these limits by assessing four ecosystem services—forest production, tree growth, sequestered carbon, and tourism potential—under drought or climate change. To support adaptation, we adapted the existing concept of ‘dynamic adaptive policy pathways’ for forest management by developing an action expiration chart, which helps to define expiry dates for forestry actions using ecosystem services delivery thresholds. We assessed services for Sitka spruce, Scots pine, and pedunculate oak on t...
  • BB

  • Actual influence cost estimation of water resources in coal mining and utilization in China

    • Authors: El-Shikha, D.; Eranki, P.L.;  Advisor: -;  Participants: - (2017)

  • This study, the first of its kind for guayule, compares the metrics of energy consumption, lifecycle environmental impacts and irrigation water productivity. Drip irrigation showed a more efficient use of the applied water by generating higher rubber (46%) and bagasse (dry matter) yields (49%) compared to flood irrigation. On the other hand, drip irrigation showed 13% higher energy consumption than flood because of the additional burdens of water pumping. Experimental field operations were the central contributor to energy consumption in both irrigation methods. By separating a crucial stage of guayule production, namely irrigation, connections emerge between various key parameters in the two irrigation methods; accordingly, the outcomes from the evaluation of these two irrigation s...
  • BB

  • Actual influence cost estimation of water resources in coal mining and utilization in China

    • Authors: Li, S.; Alun, G.;  Advisor: -;  Participants: - (2017)

  • This paper summarizes and analyzes the influences of coal mining and utilization on water resources. Quantitative indicators are used to quantify relevant influences and transform the influences from material amount to monetary amount to gain the summation of the influences in the entire process. Results show that mining of coal per ton generally causes depletion of 1.32 m3 water resources, pollution to 0.88 m3 water resources, and destruction of 0.17 m2 water ecological environment on the average, thereby making a comprehensive cost of approximately 50.61 yuan. Taking thermal power industry as an example, per-ton-coal utilization means depletion of water resources of 26.35 m3 and the comprehensive cost of 86.61 yuan. To utilize coal resources scientifically and to respond to the ob...
  • BB

  • Adaptation strategies for agricultural water management under climate change in Europe

    • Authors: Luis Garrote, L.; Iglesias, A.;  Advisor: -;  Participants: - (2017)

  • Here we characterise the main risks across European regions and evaluate adaptation strategies by reviewing over 168 highly relevant publications that appeared in the last 15 years. Based on this extensive database we characterise the effort and benefit of a number of agronomic and policy measures, aiming to develop concrete adaptation plans and responding to concrete regional challenges. The adaptation choices consider current technological perspectives and do not project future technological change; we are certain that technological change will shape some choices for adaptation in the coming decades. The greatest scope for action is in improving adaptive capacity and responding to changes in water demands, however the implementation requires revamping current water policy, adequat...