What is 1/9 arc second in meters?
What is 1/9 arc second in meters?
Arc vs. Meters
| Arc | Meters (approximate) | Used for |
|---|---|---|
| 3 arc seconds | 90 meters | World-wide SRTM |
| 1 arc second | 30 meters | DEM from topo, USA SRTM |
| 1/3 arc second | 10 meters | DEM from topo |
| 1/9 arc second | 3.4 meters | Newer DEM from LIDAR |
What is a 1/3 arc second DEM?
1/3 arc-second – This is the highest resolution seamless DEM dataset for the U.S. with full coverage of the 48 conterminous states, Hawaii, and U.S. territories. Alaska coverage is partially available now and is being expanded to statewide coverage as part of the Alaska Mapping Initiative.
What resolution is 1 arc second?
Product Specifications
| Horizontal Datum | WGS84 |
| Vertical Datum | EGM96 (Earth Gravitational Model 1996) |
| Vertical Units | Meters |
| Spatial Resolution | 1 arc-second for global coverage (~30 meters) 3 arc-seconds for global coverage (~90 meters) |
| Raster Size | 1 degree tiles |
What is arc second DEM?
The seamless 1/3 arc-second DEM layer provides coverage of the conterminous United States, Hawaii, Puerto Rico, other territorial islands, and in limited areas of Alaska. The seamless 1/3 arc-second DEM is available as pre-staged products tiled in 1 degree blocks in Erdas .
What does 3 arc second mean?
Since an arc second is 1/3600 of a degree, elevation values in a 3 arc-second DEM are spaced 1/1200 degree apart, representing a grid cell about 66 meters “wide” by 93 meters “tall” at 45º latitude.
What resolution is 1/3 arc second?
approximately 10 m
This is a tiled collection of the 3D Elevation Program (3DEP) and is 1/3 arc-second (approximately 10 m) resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States.
What distance is an arc-second?
At the equator, an arc-second of longitude approximately equals an arc-second of latitude, which is 1/60th of a nautical mile (or 101.27 feet or 30.87 meters).