Question about making a cross-section with grdimage

Q&A
1

Hi there,

Using the following xyz file xyz_example.txt (165 Bytes) and the two following commands:

awk '{print $1, 6370-$2, $3}' xyz_example.txt| gmt surface -R0/5/6280/6370 -I5m/10k -Gt.nc

gmt grdimage t.nc -Baf -B+t -R0/5/6280/6370  -JPa30z -pdf cross_section

I am able to create a cross-section that looks like that:
cross_section.pdf (8.0 KB)

I was wondering whether there is a way to make the grids follow the curvature of the plot’s frame (so there are no gaps in the plot’s edges).

2

Just pick smaller gridding increments until it does not bother you anymore, e.g., -I1m/1

3

Have you try selecting a region (in surface) slightly bigger than the one use for grdimage?

4

Use -R0/6/6270/6380

awk '{print $1, 6370-$2, $3}' xyz_example.txt| gmt surface -R0/6/6270/6380 -I5m/10k -Gt.nc
gmt grdimage t.nc -Baf -B+t -R0/5/6280/6370  -JPa30z -png cross_section

cross_section
cross_section3662×787 48.8 KB

5

Thanks a lot for the help!
In the case I would want to use xyz2grd like below (with larger grinding increments):

awk '{print $1, 6370-$2, $3}' xyz_example.txt| gmt xyz2grd -R0/5/6280/6370 -I50m/20k -Gt.nc
gmt grdimage t.nc -Baf -B+t -R0/5/6280/6370  -JPa30z  -png cross_section

That gives the following:

cross_section
cross_section3662×787 39.7 KB

I was wondering if there is a way to plot the grids/cells looking something like the image below?
cell_example

6

You would need grdview -T for that.

7

Unfortunately grdview -T has a bug if -C is not given so you will need to create a CPT and pass it via -C for this to work until the bug fix is merged ( I just submitted a PR).

8

Thanks again, grdview -T works great!