Hi Derek,
I just noticed that you'd written your question yesterday to the
contact_ferret mail list. Questions like these, "how to do xyz in
Ferret",
should go to the Users List instead - that way the questions and
answers are part of the documentation for everyone to see and to refer
to later by searching the archives. So, please join up by following the
directions here-
http://ferret.pmel.noaa.gov/Ferret/email-users-group
One easy way to mark a grid, whether on a map projection or any plot,
is to put a small symbol at the grid-cell centers. Here's how to do it
for a map projection
yes? use etopo60
yes? set reg/x=`360-145`:`360-50`/y=40:85
!-> set reg/x=215:310/y=40:85
yes? go mp_stereographic_north
yes? set grid rose
yes? go mp_aspect
yes? fill/noax rose,x_page,y_page
yes? go mp_land_detail 1 overlay 1 1 blue
yes? plot/vs/over/sym=dot/nolab x_page, y_page ! mark
grid cell centers
The variables x_page and y_page are defined using the x and y
locations of the grid, so this marks the grid locations on the
projected plot.
Or to draw lines representing the cell boxes, you could use the
script mp_graticule.jnl which uses contour commands to contour along
some set spacing of longitudes and latitudes. If your original grid is
regularly-spaced you can set the delta-values in the arguments to the
script to match the grid resolution. To see how that script is called,
yes? go/help mp_graticule
Ansley
Derek Tsui wrote:
Thanks! It works perfectly. My next question would be, is there
a way draw the grid cells in this projection? I've found an example to
draw boxes using ppl aline but don't think it'll work in my case.
Derek
On Thu, Apr 16, 2009 at 4:45 PM, Ansley
Manke <Ansley.B.Manke@xxxxxxxx>
wrote:
Hi Derek,
Thanks for the
report. This has to do with the way you happened to set the region. If
you set the region so that the values lie within x=0:360 then the lines
will be drawn. The script mp_land_detail is smart enough to draw lines
outside x=0:360 for the continental boundaries but it doesn't do that
for the other choices; states/provinces, rivers, and so on.
We'll fix this in the script, but you can easily get the right plot
with this script (your commands but another dataset)
yes? use etopo20
yes? set reg/x=`360-145`:`360-50`/y=40:85
!-> set reg/x=215:310/y=40:85
yes? go mp_stereographic_north
yes? set grid rose
yes? go mp_aspect
yes? fill/noax rose,x_page,y_page
yes? go mp_land_detail 1 overlay 1 1 blue
Derek Tsui wrote:
Hi,
I'm trying to graph in stereograph projection by following
the
examples. When I set the region X=0:360 and Y=00:90 ,
countries/states/rivers are drawn. But when I set the region to focus
on Canada , only the continent outline is being drawn. Please see
attached.
Source Code:
set data orog
set region/x=-145:-50/y=40:85
go mp_stereographic_north
set grid orog
go mp_aspect
contour/fill orog, x_page, y_page
go mp_land_detail 1 overlay 1 1 blue
Thanks,
Derek
Derek Tsui wrote:
Thanks! It works perfectly. My next question would be, is there
a way draw the grid cells in this projection? I've found an example to
draw boxes using ppl aline but don't think it'll work in my case.
Derek
On Thu, Apr 16, 2009 at 4:45 PM, Ansley
Manke <Ansley.B.Manke@xxxxxxxx>
wrote:
Hi Derek,
Thanks for the report. This has to do with the way you happened to set
the region. If you set the region so that the values lie within
x=0:360 then the lines will be drawn. The script mp_land_detail is
smart enough to draw lines outside x=0:360 for the continental
boundaries but it doesn't do that for the other choices;
states/provinces, rivers, and so on.
We'll fix this in the script, but you can easily get the right plot
with this script (your commands but another dataset)
yes? use etopo20
yes? set reg/x=`360-145`:`360-50`/y=40:85
!-> set reg/x=215:310/y=40:85
yes? go mp_stereographic_north
yes? set grid rose
yes? go mp_aspect
yes? fill/noax rose,x_page,y_page
yes? go mp_land_detail 1 overlay 1 1 blue
Derek Tsui wrote:
Hi,
I'm trying to graph in stereograph projection by following
the examples. When I set the region X=0:360 and Y=00:90 ,
countries/states/rivers are drawn. But when I set the region to focus
on Canada , only the continent outline is being drawn. Please see
attached.
Source Code:
set data orog
set region/x=-145:-50/y=40:85
go mp_stereographic_north
set grid orog
go mp_aspect
contour/fill orog, x_page, y_page
go mp_land_detail 1 overlay 1 1 blue
Thanks,
Derek
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