Rich,
> No, I'm not using wrap around in the longitudinal direction. I'll add a
> column on the right side the same as the left side. Then would I need to
> change the XC1 or XCM values, so it's -180 to 180+1 grid box?
The value of XC1 should be -180 and the value of XCM +180, reflecting the
fact that the left and right edges of your grid map into the same meridian
on the globe (-180 = 180W = 180E = +180). Making them -180 and +180 allows
CONPACK to do linear interpolation between the two and get meaningful numbers.
By the way, all that I have said is based on the assumption that the data
in your original array (without the repeated values at the ends of the rows)
were stored such that a first subscript of I corresponded to a longitude of
-180.+REAL(I-1)*(360./REAL(M)); in particular, data for I=1 was at longitude
-180 and data for I=M was at longitude -180.+REAL(M-1)*(360./REAL(M)). If
the first data point on each row was at some longitude other than -180, you
would have to adjust XC1 and XCM appropriately. For example, if the first
data point on each row is at 75E (and you duplicate that point at the end of
the row), then you should set XC1 to 75 and XCM to 435 (75+360). The bottom
line is that XC1 should be set to the longitude corresponding to a first
subscript of 1 and XCM to the longitude corresponding to a final subscript
of M and you should adjust these values (by adding and subtracting multiples
of 360) so that XCM is greater than XC1 and less than or equal to XCM+360.
> How would I add a latitude row? I can see adding a longitude column to
> rotate the plot, but not a latitude row. What would I add, a row at the
> top, or bottom?
The problem shouldn't arise in the other direction. Even if you're using
a global array of data, the data along each meridian will typically run
from -90 (the South Pole) to +90 (the North Pole) and those two poles are
opposite each other on the globe. In this regard, latitude and longitude
are fundamentally different from each other.
Dave Kennison
This archive was generated by hypermail 2b29 : Wed Jun 28 2000 - 09:40:34 MDT