Dataset DOI: 10.5061/dryad.15dv41p7w

Description of the data and file structure

Data and computer code for "Estimating red deer (Cervus elaphus) population density using drones in a steep and rugged terrain"

Files and variables

File: SiteData.rda

Description: The main data file (see below for the complete archived repository including data overviews and computer code).

Variables:

The SiteData.rda file contains data.frame SiteData with the following variables:

• Survey: A single flight conducted using a UAV to collect data over a designated area. A total of 31 survey flights were conducted in this study.
• Study_area: A specific geographic location selected for conducting surveys. For this study, four sampling areas were selected: Haugen, RC%, Sprakehaug, and SC8re BjC8rkum.
• Route: A predetermined flight path followed by the UAV during a survey. In this study, each sampling area contained between three and five routes, and each route was surveyed between one and three times.
• Month: The month during which a survey was conducted (March or April).
• Date: The specific date a survey was conducted (R Date format).
• Flight_Altitude: Programmed flight altitude above ground in meters, based on the digital elevation model.
• Focal_image: Unique identifier for the focal image constituting the Site. All focal images are non-overlapping with other focal images from the same survey.
• Site: Site number within Survey, numbered consecutively from 1 within each Survey.
• File: File name for the Folcal image. Each file name corresponds to a raster image used for extracting information such as mean elevation, distance to the field, etc. from a Digital Elevation Model (DEM) (see variables below).
• Weather: The weather conditions during a survey as noted by Yr.no and confirmed by observations, such as clear, mostly clear, mostly overcast, mostly sunny, overcast, slightly overcast, or sunny.
• Temperature_C: The temperature (in degrees Celsius) at the end of a survey.
• Snow: Whether the survey area was covered with snow during the survey (yes or no). A survey area was considered snow-covered if more than 50% of the aerial images displayed snow-covered surfaces.
• Area: The total area (in square meters) covered by a site within a focal image.
• mean_x: The mean UTM zone 33V x-coordinate (east) of all pixels within a focal image.
• mean_y: The mean UTM zone 33V y-coordinate (north) of all pixels within a focal image.
• elevation_at_mean_pos: The elevation at the average east (x) and north (y) UTM coordinate of the site, derived from a DEM.
• mean_elevation: The average elevation (in meters above sea level) of a site, calculated as the mean of all elevation values within the site, derived from a DEM.
• min_elevation: The lowest elevation (in meters above sea level) within the site, derived from a DEM.
• max_elevation: The highest elevation (in meters above sea level) within the site, derived from a DEM.
• proportion_no_field: The proportion of the site that does not consist of fields. Calculated as the area of non-field land cover (e.g., forest, water, bare ground) divided by the total area of the site, derived from a polygon file.
• field_dist_at_mean_pos: The distance (in meters) from the average east (x) and north (y) UTM coordinate of the site to the nearest field, derived from a DEM and a habitat polygon file.
• mean_field_dist: The average distance (in meters) from all points within a site to the nearest field, calculated as the mean of all distance values within the site, derived from a DEM and a habitat polygon file.
• min_field_dist: The shortest distance (in meters) from any point within a site to the nearest field, derived from a DEM and a habitat polygon file.
• max_field_dist: The longest distance (in meters) from any point within a site to the nearest field, derived from a DEM and a habitat polygon file.
• proportion_forest: The proportion of a site that consists of forested land, calculated as the area of forest cover divided by the total area of the site, derived from a habitat polygon file.
• forest_dist_at_mean_pos: The distance (in meters) from the average east (x) and north (y) UTM coordinate of a site to the nearest forested area, derived from a DEM and a habitat polygon file.
• mean_forest_dist: The average distance (in meters) from all points within a site to the nearest forested area, calculated as the mean of all distance values within the site, derived from a DEM and a habitat polygon file.
• min_forest_dist: The shortest distance (in meters) from any point within a site to the nearest forested area, derived from a DEM and a habitat polygon file.
• max_forest_dist: The longest distance (in meters) from any point within a site to the nearest forested area, derived from a DEM and a habitat polygon file.
• aspect_deg: The average compass direction (in degrees) of the slope within a site, calculated as the mean of all aspect values within the site, derived from a DEM. Aspect is measured as degree north from 0B0 to 360B0, where 0B0 represents north, 90B0 represents east, 180B0 represents south, and 270B0 represents west.
• slope_deg: The average steepness (in degrees) of the terrain within a site, calculated as the mean of all slope values within the site, derived from a DEM. Slope represents the angle between the ground surface and a horizontal plane, with 0B0 indicating flat terrain and higher values indicating steeper slopes.
• n_both: The number of red deer detected by both observer 1 and observer 2 within the site.
• n_only_ab: The number of red deer detected only by observer 1 within the site.
• n_only_jb: The number of red deer detected only by observer 2 within the site.

File: SuppInfo.html (Zenodo - Supplemental information)

Description: Supplemental Information accompanying the paper.

File: dronedeer-main.zip (Zenodo - Software)

Description: Data and computer code for analysis. This is an archived version of the GitHub repository https://github.com/torbjore/dronedeer. See the 'README.md' or 'README.html' in the root directory for content of the sub-directories. For a detailed description of the original data file with its variables, see 'data\SiteDataInfo.html' (also available here). Data overviews are given in the Supporting Information accompanying the paper (Quarto source code included in the repository under 'Supplemental_Info').

File: Deer_drone-master.zip (Zenodo - Software)

Description: Collection of tools used to map drone images to digital elevation models (DEMs) with no prior photogrammetric processing. See the 'README.md' in the zip-archive - also available on GitHub at https://github.com/ArcticSnow/Deer_drone. 

Code/software

R (version 4.5.1), NIMBLE (R package version 1.3.0), Quarto (version 1.6.42), and Python (version 3.7)

Access information

Other publicly accessible locations of the data:

• https://github.com/torbjore/dronedeer