In recent years, significant progress has been made in the creation of equipment that captures the so-called personal spatial data records. The size and its price compared to other equipment, make it ...ideal for works related to historical-artistic heritage. In this research, a comparison is made between two scanners used in geodetic measurements for the purpose of Building Information Modeling (BIM) in historic buildings. A stationary BLK360 personal scanner has been chosen, which is considered to be a scanner that is easy to use and very operational in transport. Despite its precision, this equipment has been used in numerous Scan-to-BIM studies. To know the reliability conditions of the equipment, the Riegl VZ400i scanner, a state-of-the-art stationary scanner, is taken as a reference. The objective is to know the precision of both teams to develop planimetric surveys of a historic building in BIM. The methodology used is based on comparing both point clouds, knowing the density and organization and the attributes that can help as parameters in the BIM methodology. Also, and as an auxiliary base, two topographic equipment, a total station and a state-of-the-art laser measurer were used, and the precision of both was analyzed. The results show that the differences between the PLS and TLS are not excessively large, reaching differences of 10 mm in small lengths and 16 mm in longer lengths and, therefore, admissible for a Scan to BIM procedure.
•Comparison is made between two scanners used in geodetic measurements for the purpose of Building Information Modeling (BIM) in historic buildings.•Equipment evaluation that captures the so-called personal spatial data records.•Assessment of the building and information model.
Seasonal snow cover in the dry forests of the American West provides essential water resources to both human and natural systems. The structure of trees and their arrangement across the landscape are ...important drivers of snow cover distribution across these forests, varying widely in both space and time. We used unmanned aerial vehicle (UAV) multispectral imagery and Structure-from-Motion (SfM) models to quantify rapidly melting snow cover dynamics and examine the effects of forest structure shading on persistent snow cover in a recently thinned ponderosa pine forest. Using repeat UAV multispectral imagery (n = 11 dates) across the 76 ha forest, we first developed a rapid and effective method for identifying persistent snow cover with 90.2% overall accuracy. The SfM model correctly identified 98% (n = 1280) of the trees, when compared with terrestrial laser scanner validation data. Using the SfM-derived forest structure variables, we then found that canopy shading associated with the vertical and horizontal metrics was a significant driver of persistent snow cover patches (R2 = 0.70). The results indicate that UAV image-derived forest structure metrics can be used to accurately predict snow patch size and persistence. Our results provide insight into the importance of forest structure, specifically canopy shading, in the amount and distribution of persistent seasonal snow cover in a typical dry forest environment. An operational understanding of forest structure effects on snow cover will help drive forest management that can target snow cover dynamics in addition to forest health.
COMPARISON OF LEICA BLK360 AND LEICA BLK2GO ON CHOSEN TEST OBJECTS Dlesk, A.; Vach, K.; Šedina, J. ...
International archives of the photogrammetry, remote sensing and spatial information sciences.,
02/2022, Letnik:
XLVI-5/W1-2022
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The contribution deals with the comparison of two laser scanners manufactured by Leica company. In BIM modelling, there is a need for fast and accurate gathering of spatial data, e.g. point clouds. ...Those data can be gathered by photogrammetry or laser scanning. Last years on the market, there occurred some light and easy-to-use alternatives to classic laser scanners. There were chosen two scanners that belong to the easy-to-use category. The first scanner is stationary Leica BLK360 and the second scanner is Leica BLK2GO which is a handheld scanner based on SLAM technology. Both laser scanners were tested on three different test objects. The first object is an administrative building, the second object is a historical administrative building and the third object is the vaults of the church. In all cases, only the indoor side of the objects was measured. The point clouds were compared to each other and the comparison was discussed. The parameters derived from the point clouds were also compared to the parameters read in the original documentation of the object. The comparison of the parameters may show, how those point clouds are usable for the final BIM modelling.
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