# EPSG:9617

### Attributes

Data source: EPSG

Information source: EPSG guidance note #7-2, http://www.epsg.org, after Institut de Geomatica; Barcelona.

Revision date: 2011-07-10

### Formula

```Note: These formulas have been transcribed from EPSG Guidance Note #7-2. Users are encouraged to use that document rather than the text which follows as reference because limitations in the transcription will be avoided.

The polynomial expressions are:

dLat seconds = A0 + (A1*lat) + (A2*lon) + (A3*H)
dLon seconds = B00 + B0 + (B1*lat) + (B2*lon) + (B3*H)

where latitude lat and longitude lon are in decimal degrees referred to the Madrid 1870 (Madrid) geographic coordinate reference system and H is gravity-related height in metres.  B00 is the longitude (in seconds) of the Madrid meridian measured from the Greenwich meridian; it is the value to be applied to a longitude relative to the Madrid meridian to transform it to a longitude relative to the Greenwich meridan.

The results of these expressions are applied through the formulae:
Lat(ED50) = Lat(M1870(M))  + dLat
and Lon(ED50) = Lon(M1870(M))  + dLon.```

### Example

```Input point coordinate system: Madrid 1870 (Madrid) (geographic 3D)
Latitude    =  42 deg 38 min 52.77 sec N
= 42.647992 degrees
Longitude  =    3 deg 39 min 34.57 sec E of Madrid
= +3.659603 degrees from the Madrid meridian.
Height        =  0 m

For the north zone transformation:
A0 = 11.328779
A1 = -0.1674
A2 = -0.03852
A3 = 0.0000379
B00 = -13276.58
B0 = 2.5079425
B1 = 0.08352
B2 = -0.00864
B3 = -0.0000038

dLat = +4.05 seconds

Then ED50 latitude = 42 deg 38 min 52.77 sec N + 4.05sec = 42 deg 38 min 56.82 sec N

dLon = -13270.54 seconds  = -3 deg 41 min 10.54 sec

Then ED50 longitude = 3 deg 39 min 34.57 sec E - 3 deg 41 min 10.54 sec = 0 deg 01 min 35.97 sec W of Greenwich.```