# Orthometric elevation and ellipsoidal height

Hello friends.

I have worked a survey as follows:

1. Base in unknown point, base in static mode, average single, base height = 1.733 m.

2. I have made a ppk, I have taken several points and details, and in my raw csv I have seen both heights for each point.

3. In office, I processed the data, and I got the result (I attached the result file) in height as 32.5712 m.

My questions are:

1. The height in result file (32.5712 m) is an elipsoidal elevation, right?

2. How I can obtain the orthometric elevation of my base point ? It is right to apply the aritmethic difference between both elevations in the raw csv file?

3. When I need to use the base point to make rtk, I have to place my base in RTK mode, Kinematic, and manual coordinates, and the elevation must be elipsoidal or othometric?

Emlid Studio app version. - 1.4

Raw data you use for post-processing.

In shared files, the ignXXX file is the CORS data.

Thank you for your responses and help me clear up the matter of heights.

Responding without having looked at the Google Drive data and without knowing the process you went through ‘in office’ to come up with a height of 32.5712m it is difficult for me to say with any confidence if it is ortho or ellipsoidal. If you used ellipsoidal heights in all of your office processing, then it is most likely ellipsoidal height as well.

formula for orthometric height is …
orthometric height = ellipsoidal height - geoid height

When setting up the base in RTK mode (kinematic and manual coordinates), I am prompted to input the ellipsoidal height.

Emlid Studio solo trabaja con alturas elipsoidales. Luego en Emlid Flow puedes importar los puntos y obtener las alturas ortométricas según el modelo geoidal que elijas.
Aún no puedo ver los archivos, habría que revisar la altura del CORS para saber si está todo bien.
Saludos!

2 Likes

Hi Jaime,

Yep, since Emlid Studio provides ellipsoidal heights only. Agree with Javier on this.

This height is related to the same datum as your base. So if you used WGS84 coordinates of the base in processing, this height is in WGS84 as well.

What orthometric height do you need? EGM2008?

I also second Javier on this. You can use Emlid Flow for the conversion. The workflow is described in this post.

If you enter the position in the Base settings manually, then the height should be ellipsoidal. But it’s also possible to set the base using local coordinates and orthometric height. Check these posts to learn more about both ways: