Title: Temperature (degrees fahrenheit) for June
Type of Map: raster Number of Categories: 215
Rows: 2250
Columns: 4500
Total Cells: 10125000
Data Source:
IIASA GRID-Geneva
Comments:
The IIASA mean monthly temperature data set consists of
nearly 6300 records of data (Leemans & Cramer, 1990).
Seasonal patterns can clearly be seen; the adiabatic lapse
rate to correct for the orographic effects was successfully
applied by the authors. This was based on elevation values
from a separate global topographic data set, and has
improved the utility at a regional scale, particularly in
mountainous areas.
The original category values are in terms of centigrade
degrees in tenths, necessitating the use of real numbers
or division by ten. The data files are 2-byte (16-bit)
with truncated temperature values (both positive and
negative but rounded to the nearest integer value). Non-
land area (i.e. oceans) have a value of 215.
Since GRASS is able to handle the negative values,
the following r.mapcalc was used:
if(temp.month>255,temp.month-65536,temp.month)
This created a category file where the category number
equaled the category value, making this map easier to
understand.
***NOTE*** There are no longer negative values in this
file. Zero degrees Fahrenheit is now a value
of 100 in the file.