DTED level comparison

DTED levels primarily describe angular post spacing. Approximate ground spacing varies with latitude, and source quality remains independent of the level name.

Level	Nominal post spacing	Approximate spacing at equator	Typical matrix for a 1° cell
DTED0	30 arc-seconds	900 m	121 × 121
DTED1	3 arc-seconds	90 m	1,201 × 1,201
DTED2	1 arc-second	30 m	3,601 × 3,601
DTED3	Higher density	Source-dependent	Source-dependent

Matrix dimensions include shared boundary posts. Implementations and source products should be checked against their manifest and specification rather than inferred from file size alone.

DTED.org delivery layouts

Each active state endpoint publishes:

Layout	Purpose
Native quadrant archives	ATAK Elevation Tools and compatible TAK clients
Simple DTED Streamer index and root cells	Optional ATAK plugin path
Preference file, QR, and TAK configuration package	Streaming configuration
State zipped-DTED package	Offline terrain import
Manifest, coverage, and quality summary	Release evidence and discovery

See Getting started for client setup and Terrain science and data lineage before comparing sources by resolution alone.

Comparing terrain sources for a state

When a state has more than one source, its endpoint includes a source chooser and a comparison of terrain model, native posting, delivered DTED level, vertical reference, fallback policy, quality result, exact enhanced coverage, common uses, and limitations. The stable comparison URL is:

https://dted.org/states/STATE/

For example, dted.org/states/ca/ compares the available California sources. Every comparison map uses the same bounds and shows the source-only enhanced cells in that release's offline DTED package. This avoids mistaking canonical SDS fallback entries for enhanced source coverage.

The canonical state endpoint remains the general default. A published source-specific alternative is independent and never silently fills missing cells from the canonical SRTM baseline. A source marked Evaluation preview has passed automated QA but has not completed TAK client validation and production promotion.

Machine-readable consumers can request GET /api/v1/regions/STATE/terrain-sources. This regional catalog includes eligible public evaluation previews. The TAK product catalog remains production-only.