Document how to authenticate to Geostreams

modules/data.atmosphere/R/download.Geostreams.R

@@ -1,7 +1,7 @@
 #' Download Geostreams data from Clowder API
 #'
 #' @param outfolder directory in which to save json result. Will be created if necessary
-#' @param sitename character. Should match a geostreams sensor_name
+#' @param sitename character. Must match a Geostreams sensor_name
 #' @param start_date,end_date datetime
 #' @param url base url for Clowder host
 #' @param key,user,pass authentication info for Clowder host.
@@ -13,6 +13,21 @@
 #'   `~/.pecan.clowder.xml`, and finally if no keys or passwords are found there it
 #'   attempts to connect unauthenticated.
 #'
+#' If using `~/.pecan.clowder.xml`, it must be a valid PEcAn-formatted XML settings
+#'  file and must contain a \code{<clowder>} key that specifies hostname, user, and
+#'  password for your Clowder server:
+#'
+#' \code{\preformatted{
+#'   <?xml version="1.0"?>
+#'   <pecan>
+#'     <clowder>
+#'       <hostname>terraref.ncsa.illinois.edu</hostname>
+#'       <user>yourname</user>
+#'       <password>superSecretPassw0rd</password>
+#'     </clowder>
+#'   </pecan>
+#' }}
+#'
 #' @export
 #' @author Harsh Agrawal, Chris Black
 #' @examples \dontrun{