CrawlModels {rNOMADS} | R Documentation |
Get Available Model Runs
Description
This function determine which instances of a given model are available for download.
Usage
CrawlModels(abbrev = NULL, model.url = NULL, depth = NULL, verbose = TRUE)
Arguments
abbrev |
The model abbreviation, see |
model.url |
A URL to use instead of using the abbreviations in |
depth |
How many model instances to return.
This avoids having to download the entire model list (sometimes several hundred) if only the first few instances are required.
Defaults to |
verbose |
Print out each link as it is discovered.
Defaults to |
Details
This function calls WebCrawler
, a recursive algorithm that discovers each link available in the URL provided.
It then searches each link in turn, and follows those links until it reaches a dead end.
At that point, it returns the URL.
For the model pages on the NOMADS web site, each dead end is a model instance that can be examined using ParseModelPage
or have data retrieved from it using GribGrab
.
Value
urls.out |
A list of web page addresses, each of which corresponds to a model instance. |
Note
It is a good idea to set depth
to a small number rather than leave it at the default value.
Some models (such as the Global Forecast System) have a large number of instances, and crawling each one can take a lot of time.
I recommend depth = 2
, since the first URL may not have an active model on it yet if the model is still being uploaded to the server.
In that case,the first URL will contain no data, and the second URL can be used instead.
Author(s)
Daniel C. Bowman danny.c.bowman@gmail.com
See Also
WebCrawler
, ParseModelPage
, NOMADSRealTimeList
, GribGrab
Examples
#Get the latest 5 instances
#for the Global Forecast System 0.5 degree model
## Not run: urls.out <- CrawlModels(abbrev = "gfs_0p50", depth = 5)