Resolution Assessment and Spatial Characterization of Airborne LIDAR Data: Assateague Island National Seashore.

Assateague;Resolution;LIDAR

Shroyer, William James ; Dr. Hugh A. Devine, Committee Chair,Shroyer, William James ; Dr. Hugh A. Devine ; Committee Chair

University:North Carolina State University

关键词: Assateague;    Resolution;    LIDAR;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/1174/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

The purpose of this research was to determine the effect of spatial data resolution change on the representation of barrier island topographic surfaces.A study area of approximately three kilometers of the northern section of the Maryland portion of Assateague Island National Seashore (ASIS) was chosen.Utilizing the Level 4 LIDAR data, provided by the United States Geological Survey in GeoTiff format, the data was converted into raster elevation Grids at four resolutions (0.5 m, 1 m, 2 m, and 10 m).Using the 1999 and 2001 LIDAR surveys the grids were processed as Digital Elevation Models (DEM's) at the varying resolutions and compared.An interpretation of volumetric change was established to determine the effect of resolution on representing change in topography.Subtraction of the elevation grids for 1999 and 2001 was used to estimate the volumetric change.Slope and hillshade surfaces were also used as a means to determine the variations in spatial distribution that occur when changing resolution.Although the amount of change in volume varied between resolutions the spatial distribution of change in each surface was consistent between resolutions.Using an analysis of variance (ANOVA) of mean elevation change, revealed no significant difference with resolution.There was also very little slope change observed when comparing each resolution.Subtracting the slope surfaces and reclassifying the values into slope increase, slope decrease and no change provided insight into the spatial distribution of slope change.Throughout the varying resolutions the position in which these slope classifications were represented was consistent.The visual comparison of hillshade surfaces and topographic profiles represented the generalization that takes place when resampling to coarser resolutions.As the cell size increased with each resolution, the profile of the topography represented less relief.This was also illustrated in the hillshade surfaces of each resolution as the topographic features became more apparent from the 0.5 m to the 10 m sizes.Constantly interrupted by coastal processes, the barrier island system exists in a continued flux of change.This constant change presents coastal scientists with a difficult challenge in measuring and monitoring the barrier island topography.Dependant upon application, the use of precision LIDAR surveys allows for an assessment of the continuing process of barrier island evolution.