Delineating bedrock outcrops and shallow superficial deposits in Southern Finland with LiDAR DEMs
Viitanen, Erkko (2024-11-07)
Delineating bedrock outcrops and shallow superficial deposits in Southern Finland with LiDAR DEMs
(07.11.2024)
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
avoin
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2024111291035
https://urn.fi/URN:NBN:fi-fe2024111291035
Tiivistelmä
This study utilizes visual identification of topographical textures of bedrock outcrops and shallow
superficial deposit areas (BOSS) that can be interpreted from remotely sensed Light Detection and
Ranging (LiDAR) based Digital Elevation Models (DEM) from four different study areas in S Finland.
Accuracy of new delineations for BOSS areas were tested on the field and with elevation profiles in
ArcGIS Pro. These four study sites represent different Quaternary deposits and varying amounts of
BOSS areas. Main research goals for this thesis were the measurement of accuracy and the amount of
new BOSS areas digitized in 1: 4000, describe the textural characteristics associated with shallow
superficial deposits and bedrock outcrops visible on DEM, determine the geological processes affected
to the distribution and origin of shallow superficial deposits in recently glaciated landscapes. Results
suggest that there is great potential for the refinement and update of BOSS areas via LiDAR DEM usage
and applications. Bedrock outcrop areas were increased by 30% while shallow superficial deposit areas
decreased by 1.3% from the original BOSS data produced by MML>K in a scale of 1: 10 000. New
delineations were on average 3.5 m more accurate than the existing ones, interpreted from 2 terrain
profiles from Muurla. Overall ruggedness of BOSS textures is apparent on DEM maps, and Terrain
Ruggedness Index (TRI) supports this. Outcrops were visually easier to delineate on shaded relief maps
compared to shallow superficial deposits. This is because of the protrusions, slopes, edges and fracture
surfaces they exhibit. In Southern Finland glacial and glaciofluvial processes have impacted greatly on
the origin and distribution of BOSS areas. Bedrock structures, rock type and bedding plane orientations
also play important role. This study emphasises also the importance of field work and field inspections
during a re-survey of BOSS areas.
superficial deposit areas (BOSS) that can be interpreted from remotely sensed Light Detection and
Ranging (LiDAR) based Digital Elevation Models (DEM) from four different study areas in S Finland.
Accuracy of new delineations for BOSS areas were tested on the field and with elevation profiles in
ArcGIS Pro. These four study sites represent different Quaternary deposits and varying amounts of
BOSS areas. Main research goals for this thesis were the measurement of accuracy and the amount of
new BOSS areas digitized in 1: 4000, describe the textural characteristics associated with shallow
superficial deposits and bedrock outcrops visible on DEM, determine the geological processes affected
to the distribution and origin of shallow superficial deposits in recently glaciated landscapes. Results
suggest that there is great potential for the refinement and update of BOSS areas via LiDAR DEM usage
and applications. Bedrock outcrop areas were increased by 30% while shallow superficial deposit areas
decreased by 1.3% from the original BOSS data produced by MML>K in a scale of 1: 10 000. New
delineations were on average 3.5 m more accurate than the existing ones, interpreted from 2 terrain
profiles from Muurla. Overall ruggedness of BOSS textures is apparent on DEM maps, and Terrain
Ruggedness Index (TRI) supports this. Outcrops were visually easier to delineate on shaded relief maps
compared to shallow superficial deposits. This is because of the protrusions, slopes, edges and fracture
surfaces they exhibit. In Southern Finland glacial and glaciofluvial processes have impacted greatly on
the origin and distribution of BOSS areas. Bedrock structures, rock type and bedding plane orientations
also play important role. This study emphasises also the importance of field work and field inspections
during a re-survey of BOSS areas.