DemUtility

DemUtility (dem)

A command-line tool for managing Digital Elevation Model (DEM) databases produced or consumed by Pmad.Cartography.

Installation

Build from source (requires .NET 10):

dotnet build DemUtility

Or publish a self-contained binary:

dotnet publish DemUtility -c Release -r win-x64 --self-contained

Commands

repack – Re-compress a DEM database

Creates a copy of a DEM database with a chosen compression format. Useful for converting downloaded archives (e.g. Zip) to faster formats such as ZSTD.

dem repack --source <dir> --target <dir> [options]

Option	Short	Description	Default
--source	-s	Source directory	(required)
--target	-t	Target directory	(required)
--compression	-c	GZip, ZSTD, Brotli, or None	ZSTD
--max-cpu	-m	Maximum CPU cores to use	all cores
--keep	-k	Skip files that already exist in target	false

Example

dem repack -s ./raw-srtm -t ./srtm-zstd -c ZSTD

---

index – Build a database index

Scans a local DEM directory and writes an index.json file listing all available cells. The index is required by DemFileSystemStorage for efficient tile lookup.

dem index --path <dir>

Option	Short	Description
--path	-p	Database directory

Example

dem index -p ./srtm-zstd

---

update-index – Add missing checksums to an existing index

Calculates and appends SHA-256 checksums for any cells that are listed in an existing index.json but do not yet have a checksum entry.

dem update-index --path <dir>

Option	Short	Description
--path	-p	Database directory

---

check – Verify a database

Reads a local or HTTP-hosted DEM database, reports its content and optionally verifies file integrity via SHA-256 checksums.

dem check (--path <dir> | --url <url>) [options]

Option	Short	Description
--path	-p	Local database directory
--url	-u	HTTP base URL of the database
--verify	-v	Verify SHA-256 checksums
--sample	-n	Number of cells to randomly sample (all cells when omitted)

Examples

# Check a local database and verify all checksums
dem check -p ./srtm-zstd --verify

# Check a remote database and sample 100 random cells
dem check -u https://cdn.dem.pmad.net/SRTM1/ --verify --sample 100

Supported compression formats

Format	Extension	Notes
ZSTD	.zst	Recommended – best speed/size trade-off
GZip	.gz	Widest tool support
Brotli	.br	Best compression ratio
None	(none)	Uncompressed

Dependencies

• Pmad.Cartography
• System.CommandLine
• Pmad.ProgressTracking