On Wed, Jul 15, 2009 at 3:43 AM, benton101<benton.davies@gmail.com> wrote:
2. The command output pane states "Datum <GDA_1994> not recognised by GRASS
and no parameters found". How can I give imported data the correct meta data
for projection? I gather that this will be an EPSG identifier?
+---------------------------------------------------
| This map was produced on the Geocentric Datum of Australia 1994 (GDA94).
| Heights are referenced to the Australia Height Datum (AHD).
| For most practical purposes GDA94 coordinates and satellite derived (GPS)
| coordinates based on the World Geodetic Datum 1984 (WGS84) are the same.
|
| Example 1: Datum information on new map.
+---------------------------------------------------
Should we add WGS84 as short-cut in the datum table?
On Wed, Jul 15, 2009 at 3:43 AM, benton101<benton.davies@gmail.com> wrote:
2. The command output pane states "Datum <GDA_1994> not recognised by GRASS
and no parameters found". How can I give imported data the correct meta data
for projection? I gather that this will be an EPSG identifier?
Were you creating a new location while importing the file? If not, this message is of no significance - the projection of the location is what will be used.
+---------------------------------------------------
| This map was produced on the Geocentric Datum of Australia 1994 (GDA94).
| Heights are referenced to the Australia Height Datum (AHD).
| For most practical purposes GDA94 coordinates and satellite derived (GPS)
| coordinates based on the World Geodetic Datum 1984 (WGS84) are the same.
|
| Example 1: Datum information on new map.
+---------------------------------------------------
Should we add WGS84 as short-cut in the datum table?
No it's a datum in its own right and should have an entry in datum.table with ellipsoid GRS80 and dx=dy=dz = 0. Before adding it we would need to check what the proper EPSG-based long name should be. I suspect it might be "Geocentric_Datum_of_Australia_1994" but will need to make sure.
On Thu, Jul 16, 2009 at 12:42 AM, Paul
Kelly<paul-grass@stjohnspoint.co.uk> wrote:
On Wed, 15 Jul 2009, Markus Neteler wrote:
+---------------------------------------------------
| This map was produced on the Geocentric Datum of Australia 1994 (GDA94).
| Heights are referenced to the Australia Height Datum (AHD).
| For most practical purposes GDA94 coordinates and satellite derived
(GPS)
| coordinates based on the World Geodetic Datum 1984 (WGS84) are the same.
|
| Example 1: Datum information on new map.
+---------------------------------------------------
Should we add WGS84 as short-cut in the datum table?
No it's a datum in its own right and should have an entry in datum.table
with ellipsoid GRS80 and dx=dy=dz = 0. Before adding it we would need to
check what the proper EPSG-based long name should be. I suspect it might be
"Geocentric_Datum_of_Australia_1994" but will need to make sure.
On Thu, Jul 16, 2009 at 12:42 AM, Paul
Kelly<paul-grass@stjohnspoint.co.uk> wrote:
No it's a datum in its own right and should have an entry in datum.table
with ellipsoid GRS80 and dx=dy=dz = 0. Before adding it we would need to
check what the proper EPSG-based long name should be. I suspect it might be
"Geocentric_Datum_of_Australia_1994" but will need to make sure.
No it's a datum in its own right and should have an entry in datum.table
with ellipsoid GRS80 and dx=dy=dz = 0. Before adding it we would need to
>> check what the proper EPSG-based long name should be. I suspect it
might be "Geocentric_Datum_of_Australia_1994" but will need to make sure.
....
> OK: from http://www.epsg-registry.org/
>
> Geocentric Datum of Australia 1994
> Code: EPSG::6283
> Type: GeodeticDatum
> Status: Valid
> Domain of Validity: Australia - all states
That looks about right then - now added to all versions.
just to note that AFAIU gda94 is similar to etrs89 in that it is a plate-
locked datum. (and in the last 36 hours I can also report some tangible
observations that these plates are certainly not static!)
Hamish
ps- (OT) http://grass.itc.it/spearfish/php_grass_earthquakes.php
low priority wishes:
- how to brighten the Blue Marble colormap (RGB raster)? i.landsat.rgb?
- Richter scale is logarithmic, but bubble radius is linear classed
to int order of magnitude- the whoppers get hidden in the noise.