# "datatondc" coordinate conversion for lambert conformal

From: Patrick Reuter <preuter64_at_nyahnyahspammersnyahnyah>
Date: Wed, 25 Mar 2009 22:26:17 +0100

Dear NCL users,

Does coordinate conversion not work with lambert conformal projection
? I am using the
datatondc function to transform a boxlat/boxlon array.

....

plot = gsn_csm_map(xwks,res)

draw(plot)
frame(xwks)
x_out = new(dimsizes(boxlat),float)
y_out = new(dimsizes(boxlat),float)
datatondc(plot,boxlat, boxlon,x_out,y_out)
print("data: (" + boxlon + "," + boxlat + ") NDC: (" + x_out + ","
+ y_out +")")

.....

When I use robinson projection of my plot, I get the following desired output:

(0) data: (-1,45) NDC: (0.801934,0.392597)
(1) data: (-4,45) NDC: (0.801738,0.374937)
(2) data: (-4,43) NDC: (0.791349,0.374937)
(3) data: (-1,43) NDC: (0.791537,0.392597)
(4) data: (-1,45) NDC: (0.801934,0.392597)

However, with Lambert Conformal projection, it turns into :

(0) data: (-1,45) NDC: (1e+12,1e+12)
(1) data: (-4,45) NDC: (1e+12,1e+12)
(2) data: (-4,43) NDC: (1e+12,1e+12)
(3) data: (-1,43) NDC: (1e+12,1e+12)
(4) data: (-1,45) NDC: (1e+12,1e+12)

As you can see, the values are not converted.