| Spacing | Units | X-Pts | Y-Pts | Total Elevations | MB | |
| 1 | m | 86400 | 111000 | 9,590,400,000 | 18,292 (18 GB) | |
| 10 | m | 8640 | 11100 | 95,904,000 | 182.92 | |
| 20 | m | 4320 | 5550 | 23,976,000 | 45.73 | |
| 30 | m | 2880 | 3700 | 10,656,000 | 20.32 | |
| 50 | m | 1728 | 2220 | 3836160 | 7.32 | |
| 100 | m | 864 | 1110 | 959040 | 1.83 | |
| 250 | m | 346 | 444 | 153624 | 0.29 | |
| 1/27 | " | ~1m | 97,201 | 97,201 | 9,448,034,401 | 18,020 |
| 1/9 | " | ~3m | 32,401 | 32,401 | 1,049,824,801 | 2002 |
| 1/3 | " | ~10 m | 10,801 | 10,801 | 116,661,601 | 222.5 |
| 1 | " | ~30 m | 3601 | 3601 | 12,967,201 | 24.73 |
| 3 | " | ~90m | 1201 | 1201 | 1,442,401 | 2.75 |
| 30 | " | ~1 km | 121 | 121 | 14,641 | 0.03 |
| 5 | ' | ~10 km | 13 | 13 | 169 | 0.00 |
The number of points to cover a one degree square at the latitude of Annapolis, MD (39ºN). This assumes 2 byte integers for the elevations; most newer DEMs, especially those at higher resolution, use 4 byte reals, which would double the size of the DEM. These values also do not include any headers or metadata, which are typically a tiny fraction of the file size.
The values for spacing in geographic coordinates would not vary with latitude, while DEMs with spacing in meters will get smaller with latitude.
Actual file sizes depend on the size of the region covered by the DEM and the resolution.
Approximate metric equivalents
Last Updated on 12/4/2015