EPSG:7878 · St Helena
Astro DOS 71 / UTM zone 30S to KML & KMZ
Astro DOS 71 / UTM zone 30S (EPSG:7878) is a Transverse Mercator (UTM) coordinate system on the Astro DOS 71 datum, with coordinates in metres. Its official area of use is: St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore.
- Converter already set to EPSG:7878
- Latitude and longitude on WGS 84, as Google Earth uses
- Download the point as KML
Loading converter…
Good to know
- This is a southern-hemisphere grid: northings start at 10,000,000 m at the equator.
- Pick the UTM zone by longitude. Points outside the zone's area of use are flagged after conversion.
- Datum: Published 3-parameter shift (typically a few metres).
Convert a whole spreadsheet
- Open the web app or the Windows app, and paste your rows from Excel or open a CSV file.
- Under Coordinate system, search for “7878” and pick Astro DOS 71 / UTM zone 30S.
- Check one point you know on the map, then press Save KML or Save KMZ and open it in Google Earth.
Check points for EPSG:7878
Five points inside the area of use of Astro DOS 71 / UTM zone 30S, with their latitude and longitude on WGS 84 and their easting and northing in this grid (metres). Enter an easting and northing in the converter above: you should get the latitude and longitude shown, to a few centimetres.
| Point | Latitude | Longitude | Easting | Northing |
|---|---|---|---|---|
| Middle of the area of use | 15.96500° S | 5.72000° W | 208,303.51 | 8,233,534.33 |
| Towards the north-west | 15.89600° S | 5.79800° W | 199,845.93 | 8,241,063.80 |
| Towards the north-east | 15.89600° S | 5.64200° W | 216,561.45 | 8,241,281.25 |
| Towards the south-west | 16.03400° S | 5.79800° W | 200,051.28 | 8,225,783.40 |
| Towards the south-east | 16.03400° S | 5.64200° W | 216,755.31 | 8,226,002.53 |
Common mistakes with Astro DOS 71 / UTM zone 30S
- Easting and northing swapped. In Astro DOS 71 / UTM zone 30S the middle of the grid is near easting 208,303.51 and northing 8,233,534.33. If your easting column holds numbers like 8,233,534.33, the columns are the wrong way round and every point lands far away: swap them before converting.
- Feet entered as metres. Astro DOS 71 / UTM zone 30S is in metres. Coordinates copied from a drawing in feet must be converted first, or every point moves outwards from the grid's origin.
- Forgetting the datum. Astro DOS 71 / UTM zone 30S is not on WGS 84: published 3-parameter shift (typically a few metres). Picking a WGS 84 grid with the same projection instead leaves the points off by that amount.
- Points outside the grid's area. Astro DOS 71 / UTM zone 30S is meant for St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore. Points well outside that area convert with growing error; the converter flags them so you can choose the right grid.
- A local site grid. If every point is off by the same distance and direction, the drawing may be on a local site grid. Calibrate on three or more known control points instead.
New to this? Read how to convert easting and northing to latitude and longitude.