[GRASS-user] help with testing the location wizard for the upcoming release
Nikos Alexandris
nik at nikosalexandris.net
Fri Jun 14 10:18:51 PDT 2013
Hamish wrote:
> Hi, this is a general call for help.
Hi,
> if anyone/everyone is able to help test, we have made some fixes
> to the wxGUI new location wizard since 6.4.3rc3, which really
> need to be tested well before the final release. We think all is
> ok now, but a messed up location projection definition and ruin
> everything downstream in the location, so it's an important
> thing to be totally sure of.
> since there are so many projections and datums and ways to
> select them, it's pretty hard to test for "working/not working"
> as we usally could do. Please try throwing your local odd-ball
> CRS at it and see what happens. (check all the way through to
> 'g.proj -p' and 'g.proj -j' in the final location session. make
> sure it does what you'd expect it to do.
> specifically how datum transforms are handled, and CRSs without
> a specificed datum or specified datum terms; usuing all methods
> of defining the projection system. see trac issues #1849 and
> #1967 for further details.
[..]
Below, maybe not exactly something that helps the testing process... but,
anyway here it goes: I guess it is not possible to follow the good old text-
based way in building a custom coordinate system.
For example, like
#####################################################################
grass64 -text
[snip]
LOCATION: hgrs87_test______________ (enter list for a list of locations)
MAPSET: PERMANENT________________ (or mapsets within a location)
DATABASE:
/geo/grassdb/testing_________________________________________________
AFTER COMPLETING ALL ANSWERS, HIT <ESC><ENTER> TO CONTINUE
(OR <Ctrl-C> TO CANCEL)
#####################################################################
Would you like to create location <hgrs87_test> ? (y/n) [y]
#####################################################################
To create a new LOCATION, you will need the following information:
1. The coordinate system for the database
x,y (for imagery and other unreferenced data)
Latitude-Longitude
UTM
Other Projection
2. The zone for the UTM database
and all the necessary parameters for projections other than
Latitude-Longitude, x,y, and UTM
3. The coordinates of the area to become the default region
and the grid resolution of this region
4. A short, one-line description or title for the location
Do you have all this information? (y/n) [y]
#####################################################################
Please specify the coordinate system for location <hgrs87_test>
A x,y
B Latitude-Longitude
C UTM
D Other Projection
RETURN to cancel
> D
#####################################################################
Other Projection coordinate system? (y/n) [y]
#####################################################################
Please enter a one line description for location <hgrs87_test>
> Hellenic Geodetic Reference System 1987
=====================================================
Hellenic Geodetic Reference System 1987
=====================================================
ok? (y/n) [y]
Please specify projection name
Enter 'list' for the list of available projections
Hit RETURN to cancel request
>tmerc
Do you wish to specify a geodetic datum for this location?(y/n) [y]
Please specify datum name
Enter 'list' for the list of available datums
or 'custom' if you wish to enter custom parameters
Hit RETURN to cancel request
>custom
Please specify ellipsoid name
Enter 'list' for the list of available ellipsoids
Hit RETURN to cancel request
>grs80
Please specify datum transformation parameters in PROJ.4 syntax. Examples:
towgs84=dx,dy,dz (3-parameter transformation)
towgs84=dx,dy,dz,rx,ry,rz,m (7-parameter transformation)
nadgrids=alaska (Tables-based grid-shifting transformation)
Hit RETURN to cancel request
>towgs84=-199.87,74.79,246.62,0,0,0,0
Parameters to be used are:
"towgs84=-199.87,74.79,246.62,0,0,0,0"
Is this correct?(y/n) [y]
#####################################################################
Enter Scale Factor at the Central Meridian [1.0000000000]: 0.9996
Enter Central Parallel (23N) :0
Enter Central Meridian (96W) :24
Enter False Easting [0.0000000000]: 500000
Enter False Northing [0.0000000000]:
Enter plural form of units [meters]:
#####################################################################
...which will define a Location
--%<---
g.proj -p
-PROJ_INFO-------------------------------------------------
name : Transverse Mercator
towgs84 : -199.87,74.79,246.62,0,0,0,0
proj : tmerc
ellps : grs80
a : 6378137.0000000000
es : 0.0066943800
f : 298.2572221010
k_0 : 0.9996000000
lat_0 : 0.0000000000
lon_0 : 24.0000000000
x_0 : 500000.0000000000
y_0 : 0.0000000000
-PROJ_UNITS------------------------------------------------
unit : meter
units : meters
meters : 1.0
--->%--
All is ok using the correct epsg code (e.g. 2100). However, what about
replicating the above process with the new Wizard?
Thanks, Nikos
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