Hi all.
I'm getting confused about how does SRID works.
First, I create a Gauss-Boaga location in GRASS; I can do that either:
1. manually: proj_info file is
name: Transverse Mercator
datum: rome40
datumparams: towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
proj: tmerc
ellps: international
a: 6378388.0000000000
es: 0.0067226700
f: 297.0000000000
lat_0: 0.0000000000
lon_0: 9
k_0: 0.9996000000
x_0: 1500000.0000000000
y_0: 0.000000000
2. automagically, through EPSG code; choosing 26591 (the same SRID PostGIS
uses) I obtain the following proj_info:
name: Transverse Mercator
proj: tmerc
datum: rome40
towgs84: -104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
a: 6378388
es: 0.006722670022333322
lat_0: 0
lon_0: -3.45233333333333
k: 0.999600
x_0: 1500000
y_0: 0
pm: rome
no_defs: defined
The two are different, and this is obviously not good.
If I download points from GPS with v.in.garmin I get right placement with the
first location, but slightly wrong with the second one.
If I export GRASS vectors to PostGIS, I obtain a SRID 32767 (unknown); the
geometry column is called wkb_geometry, whereas it usually is "the_geom" (no
problem is apparent from this).
Moreover, it does not seem possible to write the table in a schema other than
public.
Then, if I try to load the PostGIS layer in QGIS, in both cases the layer is
not loaded; QGIS says:
"The table has not primary key nor oid column"
Trying the whole sequence with a new location from EPSG code:
UTM: 32632 +proj=utm +zone=32 +ellps=WGS84 +datum=WGS84 +units=m +no_defs
I get the same results (SRID 32767 in PostGIS, QGIS error).
Does anybody have a hint to help us understand (and possibly solve) all this?
All best wishes.