DEMTOOLS

A collection of Python tools for working with DEM (Digital Elevation Model) raster files.

GDAL Installation: GDAL is required for this package. For conda environments, use conda install gdal to install GDAL. For non-conda environments, download the appropriate wheel file from https://github.com/cgohlke/geospatial-wheels/releases to install GDAL.

Installation

pip install -e .

Features

• asproj: Assign a projection to GeoTIFF files without modifying pixel data (metadata only)
• chgnodata: Convert (replace) the nodata value of GeoTIFF files, updating pixel data accordingly
• defnodata: Assign a nodata value to GeoTIFF files without modifying pixel data (metadata only)
• chkdem (alias: deminfo): Check DEM raster file properties (resolution, projection, extent, nodata) — read-only
• mvdem: Relocate GeoTIFF files by setting a new upper-left coordinate, without modifying pixel data
• csv2tif: Convert a plain-numeric CSV raster grid to a GeoTIFF file
• tif2csv: Convert a GeoTIFF raster band to a plain-numeric CSV grid (the reverse of csv2tif)
• demmask: Extract the valid-data boundary of GeoTIFF files and save as shapefiles
• demext: Extract the bounding-box extent of GeoTIFF files and save as rectangle shapefiles

Usage

Command-line

# List all available commands
demtools -h

# Show details for a specific command
demtools-info csv2tif

# Assign a projection to all TIF files in the current directory
asproj -a --epsg 3826
asproj -i dem.tif -e 3826

# Convert nodata values for all TIF files in the current directory
chgnodata -a

# Convert nodata of a single file to -9999
chgnodata -i dem.tif -v -9999

# Set nodata metadata for all TIF files (no pixel data change)
defnodata -a -v -9999

# Check DEM raster properties (read-only)
chkdem -a
chkdem -i dem.tif
deminfo -i dem.tif

# Relocate a GeoTIFF by setting a new upper-left coordinate
mvdem -i dem.tif -x 500000 -y 2500000

# Convert a CSV grid to GeoTIFF (origin as lower-left or upper-left corner)
csv2tif -i grid.csv -o dem.tif --xll 250000 --yll 2500000 --cellsize 5 -e 32648
csv2tif -i grid.csv -o dem.tif --xul 250000 --yul 2500100 --cellsize 5 -e 32648

# Convert a GeoTIFF raster band back to a CSV grid
tif2csv -i dem.tif -o grid.csv

# Extract the valid-data boundary of all TIF files and save as shapefiles
demmask -a
demmask -i dem.tif -o SHP_MSK

# Extract the bounding-box extent of all TIF files and save as shapefiles
demext -a
demext -i dem.tif -o SHP_EXT

Python API

from demtools import asproj, chgnodata, defnodata, chkdem, mvdem, csv2tif, tif2csv, demmask, demext

# Assign a projection without touching pixel data
asproj.assign_projection("dem.tif", epsg=3826)

# Convert nodata value in a raster file
chgnodata.convert_nodata_value("dem.tif", output_nodata=-9999)

# Assign nodata metadata without touching pixel values
defnodata.define_nodata_value("dem.tif", nodata_value=-9999)

# Check DEM raster properties (read-only)
chkdem.check_dem_info("dem.tif")

# Relocate a raster by setting a new upper-left coordinate
mvdem.relocate_dem("dem.tif", x=500000, y=2500000)

# Convert CSV grid to GeoTIFF
csv2tif.csv_to_tif(
    input_csv="grid.csv",
    output_tif="dem.tif",
    xll=250000,
    yll=2500000,
    cellsize=5,
    nodata=-999,
    epsg=32648,
)

# Convert a GeoTIFF raster band back to a CSV grid
tif2csv.tif_to_csv(
    input_tif="dem.tif",
    output_csv="grid.csv",
)

# Extract the valid-data boundary and save as a shapefile
demmask.save_mask_boundary("dem.tif", output_dir="SHP_MSK")

# Extract the bounding-box extent and save as a shapefile
demext.save_dem_extent("dem.tif", output_dir="SHP_EXT")

Notes

• asproj, chgnodata, defnodata, and mvdem automatically create a RAS_BAK/ directory with backup copies before modifying files.
• chkdem (and its deminfo alias), tif2csv, demmask, and demext are read-only and never modify the input file.
• demmask writes shapefiles to an output directory (default SHP_MSK/), one shapefile per input TIF, each holding a single polygon covering all of that file's valid-data pixels.
• demext writes shapefiles to an output directory (default SHP_EXT/), one shapefile per input TIF, each holding a single rectangle polygon covering that file's full raster extent.
• csv2tif expects a plain numeric CSV (no headers), with rows ordered from north to south; tif2csv writes CSVs in the same row order.
• GDAL must be installed separately via conda or a pre-built wheel; it is not listed in requirements.txt as it cannot be reliably installed via pip on all platforms.