[postgis-users] Transform SAD69 to WGS84

[Felipe Costa]

Hello,

I'm trying to transform a geometry in SAD69 (srid 4291) to WGS84 (4326). The
problem which occurs is an error

ERRO:  transform: couldn't project point: -45 (geocentric transformation
missing z or ellps)

I've looked for a possible solution of this problem and I saw someone with
the same problem at
http://postgis.refractions.net/pipermail/postgis-users/2006-October/013565.html
And he found a solution at
http://postgis.refractions.net/pipermail/postgis-users/2006-October/013570.html
He discovered the variables of datum conversion for Belgian national grid
which is 31370, but I have no idea what should I do to know this variables
to my SAD69 system since my attribute proj4text in spatial_ref_sys has no
mention to the variable towgs84.
Can someone help me to discover how can I make this conversion?

Thanks in advance,

Felipe Costa
SIGLAB - INPA
Manaus - AM - Brazil
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