chm_analysis {greenR} | R Documentation |
Robust ALS GEDI CHM Analysis and Visualization
Description
-
Data Source: ALS GEDI v6 global canopy height model, Meta & WRI (2024).
-
Interactive map is downsampled for browser performance; see
max_cells_mapview
.
Usage
chm_analysis(
location = NULL,
bbox = NULL,
aoi_geojson = NULL,
chm_tif = NULL,
output_dir = "chm_output",
apply_mask = TRUE,
crop_result = TRUE,
create_plots = TRUE,
height_threshold = 2,
max_tiles = 100,
mapview_html = "chm_mapview.html",
tmap_png = "chm_tmap.png",
max_cells_mapview = 2e+05,
n_cores = parallel::detectCores() - 1,
chunk_size = 5,
cache_tiles = TRUE,
compression = "LZW",
user_agent_string = "R/chm_analysis_script (your_email_or_project_url)",
request_timeout = 300
)
Arguments
location |
Character. Place name for AOI (e.g. "Basel, Switzerland"). |
bbox |
Numeric. Bounding box (xmin, ymin, xmax, ymax, EPSG:4326). |
aoi_geojson |
Path to GeoJSON file defining AOI (overrides location/bbox). |
chm_tif |
Path to a local CHM raster (.tif). If supplied, skips tile download/mosaic. |
output_dir |
Output directory for all files. |
apply_mask |
Mask raster to AOI (default TRUE). |
crop_result |
Crop raster to AOI (default TRUE). |
create_plots |
Export static tmap and histogram (default TRUE). |
height_threshold |
Height (m) for tree coverage (default 2). |
max_tiles |
Max CHM tiles to use (default 100). |
mapview_html |
Output HTML file for interactive map. |
tmap_png |
Output PNG for publication-quality map. |
max_cells_mapview |
Maximum number of raster cells in the interactive map (default 1e5). |
n_cores |
Parallel cores for download (default: parallel::detectCores() - 1). |
chunk_size |
Tiles per parallel chunk (default 5). |
cache_tiles |
Cache tiles/AOI (default TRUE). |
compression |
Compression for output raster ("LZW", etc.). |
user_agent_string |
HTTP user agent string (for Nominatim, etc). |
request_timeout |
HTTP timeout in seconds (default 300). |
Details
End-to-end or single-raster Canopy Height Model (CHM) analysis using Meta & WRI's 1m ALS GEDI v6 global dataset. Downloads, mosaics, crops, analyzes, and visualizes CHM data for any AOI, or analyzes a user-supplied .tif directly. Outputs both publication-quality (tmap) and interactive (mapview) maps, with progress/status reporting.
CRAN policy note: This function downloads data from the internet if
location
, bbox
, or aoi_geojson
are specified and the required local files
are not present. Internet access is not permitted in CRAN checks or
non-interactive sessions. If you are running in batch, automated, or non-interactive
mode (including CRAN), you must provide all required files locally (e.g., chm_tif
, aoi_geojson
).
Value
List with: raster, stats, static_map, mapview_file, plot_hist_file, tmap_file
Examples
## Not run:
# Example 1: AOI from bounding box (Zurich, Switzerland)
res_bbox <- chm_analysis(
bbox = c(8.51, 47.36, 8.56, 47.40),
output_dir = tempdir(), max_tiles = 2, create_plots = TRUE
)
print(res_bbox$stats)
# Example 2: AOI from location string (Parc La Grange, Geneva)
res_loc <- chm_analysis(
location = "Parc La Grange, Geneva, Switzerland",
output_dir = tempdir(), max_tiles = 2
)
print(res_loc$stats)
# Example 3: Analyze a user-supplied CHM raster
# Assume you have a file "my_canopy.tif" (projected or WGS84)
res_tif <- chm_analysis(
chm_tif = "my_canopy.tif",
output_dir = tempdir(),
create_plots = TRUE,
height_threshold = 3
)
print(res_tif$stats)
## End(Not run)