I have 120 daily data sets that contain a value only when a threshold temperature is exceeded. If the threshold has been reached that pixel was assigned a value indicating the day it occurred (the Julian day), all the rest of the cells for that day were assigned a value of zero. I’d like to combine these raster data sets to create a final map indicating the Julian day when the threshold was first reached or exceeded.
I could use the raster calculator (in QGIS it would look something like this):
(“julian1” = 1) * “julian1” + (“julian2” = 2) * “julian2” + (“julian3” = 3)* “julian3”
up to 120 but I have 30 years of data parsed into 120 day blocks and it would take a really long time. I’ll bet there is a way better solution in either QGIS or ArcMap or a python script.