Region and format handling

[fdetsch]

As reported by a user, the following code

pcn <- getCHIRPS(region = c("Africa"),format = c("netcdf"),
                 tres = c("monthly"), sres = c(0.05),begin = as.Date("1982-01-01"),
                 end = as.Date("1982-01-31"), dsn = file.path(getwd(), "A"))

fails with

Error in function (type, msg, asError = TRUE) :
Server denied you to change to the given directory

for the following reasons:

• "Africa" needs to be lower case, otherwise the FTP server cannot be found;
• "netcdf" format is not available for African monthly images, see here.