Bug #707

grdpaste in GMT4 can not deal with pixel registration grid

Added by Dongdong over 2 years ago. Updated almost 2 years ago.

Status:ClosedStart date:2015-05-19
Priority:NormalDue date:
Assignee:Paul% Done:

100%

Category:-
Target version:Candidate for next bugfix release
Affected version:4.5.x Platform:

Description

I am trying to paste two grid datas from ASTER GDEM:

$ grdinfo ASTGTM2_N30E116_dem.nc 
ASTGTM2_N30E116_dem.nc: Title: 
ASTGTM2_N30E116_dem.nc: Command: 
ASTGTM2_N30E116_dem.nc: Remark: 
ASTGTM2_N30E116_dem.nc: Pixel node registration used
ASTGTM2_N30E116_dem.nc: Grid file format: cs (# 8) GMT netCDF format (short) (deprecated)                  
ASTGTM2_N30E116_dem.nc: x_min: 115.999861111 x_max: 117.000138889 x_inc: 0.000277777777778 name: meters nx: 3601
ASTGTM2_N30E116_dem.nc: y_min: 29.9998611111 y_max: 31.0001388889 y_inc: 0.000277777777778 name: meters ny: 3601
ASTGTM2_N30E116_dem.nc: z_min: -112 z_max: 1731 name: meters
ASTGTM2_N30E116_dem.nc: scale_factor: 1 add_offset: 0
$ grdinfo ASTGTM2_N30E117_dem.nc
ASTGTM2_N30E117_dem.nc: Title: 
ASTGTM2_N30E117_dem.nc: Command: 
ASTGTM2_N30E117_dem.nc: Remark: 
ASTGTM2_N30E117_dem.nc: Pixel node registration used
ASTGTM2_N30E117_dem.nc: Grid file format: cs (# 8) GMT netCDF format (short) (deprecated)                  
ASTGTM2_N30E117_dem.nc: x_min: 116.999861111 x_max: 118.000138889 x_inc: 0.000277777777778 name: meters nx: 3601
ASTGTM2_N30E117_dem.nc: y_min: 29.9998611111 y_max: 31.0001388889 y_inc: 0.000277777777778 name: meters ny: 3601
ASTGTM2_N30E117_dem.nc: z_min: -210 z_max: 1701 name: meters
ASTGTM2_N30E117_dem.nc: scale_factor: 1 add_offset: 0

The data are piexl registration, so the xmax of GridA and xmin of GridB do not have the same value.
grdpaste report that the two data do not share a common edge.

$ grdpaste ASTGTM2_N30E116_dem.nc ASTGTM2_N30E117_dem.nc -Gout.nc
grdpaste:  Grids do not share a common edge!

BTW, grdpaster in GMT5 does not have this problem.

History

#1 Updated by Paul over 2 years ago

  • Status changed from New to Feedback

Think I remember those grids. They are obviously gridline-registered grids foolishly encoded as pixel grids with 0.5 arc second extended boundaries. Very lame. Instead of going -R116/117/30/31 -I1s with gridline-registration they must believe having lots of decimals is the way to go. Sigh... I a sure Joaquim will remember this case.

#2 Updated by Joaquim over 2 years ago

I mostly remember the painful debugging sessions to deal with those crazy limits in grids like this and those geotiffs from CGIAR.
And given that it works in GMT5 I certainly do not want to repeat the experience and from my side this is a "Closed as a: Wont fix" issue.

#3 Updated by Dongdong over 2 years ago

If I am a GMT4-only user, do I have to use grd2xyz to convert the grid data to xyz file, then use xyz2grd to convert it back to grid data with gridline-registration?

#4 Updated by Joaquim over 2 years ago

No. Better to use grdedit -T and if necessary a second run of grdedit -R to set the correct limits.

#5 Updated by Paul almost 2 years ago

  • Status changed from Feedback to Closed
  • Assignee set to Paul
  • % Done changed from 0 to 100

The final solution to this issue is to use GMT5. GMT4 will not be fixed for this issue - it is too time-consuming for us to maintain beyond simple fixes.

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