it returns wrong altitude about srtm4 HOT 7 CLOSED

You're giving longitude and latitude in the wrong order: srtm4.srtm4 receives the longitude as first argument, and the latitude as second argument: https://github.com/cmla/srtm4/blob/master/srtm4.py#L204

srtm4.srtm4(8.035, 46.503)
2773.88

from srtm4.

OMG, thanks for the information.

from srtm4.

You're giving longitude and latitude in the wrong order: srtm4.srtm4 receives the longitude as first argument, and the latitude as second argument: https://github.com/cmla/srtm4/blob/master/srtm4.py#L204

srtm4.srtm4(8.035, 46.503)
2773.88

but 2773 is not 2725 there is 50 meters difference ?

from srtm4.

@berndhahnebach, as stated in the docstring of the srtm4.srtm4 function, it returns:

height(s) in meters above the WGS84 ellipsoid (not the EGM96 geoid)

If you want the height above sea level, you're most probably looking for the height with respect to the geoid.
This geographiclib online utility shows you that at your point of interest, the offset between the ellipsoid and the geoid is 50 meters, which explains the discrepancy you observe.

from srtm4.

got it. Thanks for the information.

Do you know a python module to convert the WGS84 (srtm4) into EGM96 (what is written in standard maps)?

from srtm4.

Sure!

You can use the pyproj package that relies on PROJ to do the transformation.

This snippet should do more or less what you want:

import pyproj

# WGS84 with ellipsoid height as vertical axis
ellipsoid = pyproj.CRS.from_epsg(4979)
# WGS84 with Gravity-related height (EGM96)
geoid = pyproj.CRS("EPSG:4326+5773")

trf = pyproj.Transformer.from_crs(ellipsoid, geoid)
geoid_alts = trf.transform(lats, lons, ellipsoid_alts)  # beware of the order of arguments: lats, lons

from srtm4.

great!

from srtm4.