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I have a '2015 Temp' shapefile that tells me the temp_min and temp_max for the entire year at one site. I want to make a new file from this where I have the day where temp_min fell above 40 degrees and all the following days until the first day where temp_max is above 75. Essentially, I am trying to find the growing season for a crop. For example, March 3 was the first day it hit above 40 and July 7 was the first day it hit above 75. I want to extract March 3 - July 7.

I know I can use 'Select'. But as far as I understand it, this only gets me days where it's above 40 but not all days that follow the first day when it was above 40.

Is there a way to do this?

I am using ArcGIS 10.4 for Desktop with the Spatial Analyst extension enabled.

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    Can you describe the shapefile a bit more? Each location has a point for each day? – Mattropolis Oct 12 '16 at 22:15
  • @Matthew. There is 1 file per location. Each file has 365 rows (for each day) with associated values of min temp and max temp for each day in columns. – Uma Oct 12 '16 at 22:58
  • I think you'll have to write some python code using cursors to loop through the points in order of date. When the loop encounters a temp_min > 40, then start tagging all the remaining points until temp_max > 75. After the loop all of the points you need will be tagged, and then you can Select to a new file. – Mattropolis Oct 12 '16 at 23:07
  • So, essentially you want to find the first day in a year where you have suitable temps and the last day in a year with the same then select the records in between... use summary statistics to find the date_min and date_max of your selected records (definition query temp_min > 40 and temp_max > 75) then you need select the dates in between... however dates are tricky, they can be date, int, string.. As @Matthew said we need to know more about your shapefile (field types and values) to help with that. Be thankful you're in the northern hemisphere and growing seasons don't straddle the new year. – Michael Stimson Oct 13 '16 at 0:30
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It looks like a perfect task for GIS, similar to this:

  • Convert your records to points
  • Points to line
  • Draw horizontal line – growing season threshold
  • Intersect 2 lines to find start and end of growing season (x coordinate of intersection points converted to days)

Daily temperature

I however doubt very much that raw daily data can be used for the task even in more continental climate than one shown above.

Which of green polygons (there are 37 of them) is your season? You need more robust definition of season start and end.

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