update documentation

[ericnost]

Some of the documentation needs updating in light of changes we've had to make:

• Revise EJAPI instructions to reflect new API and EJAM report
• Update field descriptions. I think these are linked to from the Threshold widget (or mobile?) but the fields available from that may have changed, not matching what's here.

See also #15

[ejanalysis]

Some of the field descriptions that EJSCREEN provided and that are linked above had inconsistent phrasing, typos, and even other types of errors in them -- in the process of replicating EJSCREEN calculations for development of EJAM, we had to clean up a lot of indicator descriptions and sometimes even fix variable names, etc. I would suggest any ongoing EJSCREEN work might want to shift to drawing on the cleaned up info that continues to be maintained in the EJAM repository.

The latest cleaned metadata about all the EJSCREEN indicators is stored by the EJAM package in an R data object called map_headernames, which was created from a spreadsheet map_headernames_2.32.6.xlsx (dev version about to be released early Sept 2025)

EJAM uses that metadata about indicators to label data in plots, summary reports, etc.

In R, if you want to see the variable names and their definitions, etc., you could get the map_headernames.rda file and do something like this:

# download the file and load the object
browseURL("https://github.com/ejanalysis/EJAM/raw/refs/heads/EJAM-v2.32.6/data/map_headernames.rda")
load("~/Downloads/map_headernames.rda") # or wherever you saved it
# look at it
t(map_headernames[1,])
# useful columns are "longname" and others:
x = map_headernames[, c("varcategory", "vartype", 'varlist', 'ejscreensort', 'apiname','acsname', 'csvname', 'rname', 'shortlabel', 'longname', 'api_description')]
x = x[order(x$varcategory, x$varlist), ]

x[, c("varlist", "apiname",  "longname")]

The EJAM-API relies on the EJAM package that I've been working on, which replicated EJSCREEN calculations using the same datasets and formulas but faster, open source code.