PRISM README file -- Map Graphics Archive
Last updated 2025-10-01


=== INFORMATION ===

The PRISM map graphics archive is an actively-updated repository of cartographic map graphics representing PRISM datasets. Every time a PRISM grid is produced or re-created, a new map graphic representing the new/updated grid is created. This is a complete one-to-one match -- every PRISM grid now has a matching map graphic. Additionally, new map graphic types are now available (see full list of types below).

Map graphics are currently produced in two versions:
 * 76 DPI ("076dpi" in filename): 836x646 - no county boundaries
 * 600 DPI ("600dpi" in filename): 6600x5100 - includes county boundaries

Map graphics archive location:  https://data.prism.oregonstate.edu/map_graphics
PRISM Datasets document (pdf):  http://prism.oregonstate.edu/documents/PRISM_datasets.pdf


=== DIRECTORY STRUCTURE ===

The map graphics archive directory structure matches the directory structure where PRISM datasets are stored.
Use this guide to navigate into the archive:

us                       [region -- once available, "hi," "ak," and "pr" will appear here as well]
|- an                    ["an" stands for "all networks" -- see our documentation for more details]
   |- png                [map graphic image format]
      |- 800m            [spatial resolution of the PRISM grid(s) used for generating map graphics]
        |- {variable}    [PRISM variable (ppt = precipitation, etc.) -- see documentation for complete list]
           |- {type}     [map graphic type]
              |- {year}  [each year contains all map graphics of the selected type, for the selected year] 


=== LIST OF MAP GRAPHIC TYPES ===

TYPE             EXPLANATION
---------------  ----------------------------------------------------------------------
annual           Annual map graphic - time series [1895-forward]
annual_anom      Annual map graphic - deviation from normal [1895-forward] 
annual_normals   Annual map graphic - normals [1991-2020 normals period]
daily            Daily map graphic - time series [1981-forward]
daily_anom       Daily map graphic - deviation from normal [not yet created]
daily_normals    Daily map graphic - normals [1991-2020 normals period]]
monthly          Monthly map graphic - time series [1895-forward]
monthly_anom     Monthly map graphic - deviation from normal [1895-forward]
monthly_normals  Monthly map graphic - normals [1991-2020 normals period]
mtd              Month-to-date map graphic - time series [1895-forward]
mtd_anom         Month-to-date map graphic - deviation from normal [1895-forward; ppt, tmean only]
quarterly_anom   Quarterly (3 month) map graphic - deviation from normal [1895-forward]