polygon_from_extent

An <code><a rd-options="" href="/link/extent?package=FedData&version=2.0.8" data-mini-rdoc="FedData::extent">extent</a></code> object, or an object from which an extent object can be retrieved.

A PROJ.4 formatted string defining the required projection. If NULL, 
the function will attempt to get the projection from x using <code><a rd-options="" href="/link/projection?package=FedData&version=2.0.8" data-mini-rdoc="FedData::projection">projection</a></code>

proj4string

Functions to automate downloading geospatial data available from
several federated data sources (mainly sources maintained by the US Federal
government). Currently, the package allows for retrieval of five datasets:
The National Elevation Dataset digital elevation models (1 and 1/3 arc-second;
USGS); The National Hydrography Dataset (USGS); The Soil Survey Geographic
(SSURGO) database from the National Cooperative Soil Survey (NCSS), which is
led by the Natural Resources Conservation Service (NRCS) under the USDA; the
Global Historical Climatology Network (GHCN), coordinated by National Climatic
Data Center at NOAA; and the International Tree Ring Data Bank. Additional
data sources are in the works, including global DEM resources (ETOPO1, ETOPO5,
ETOPO30, SRTM), global soils (HWSD), MODIS satellite data products, the National
Atlas (US), Natural Earth, PRISM, and WorldClim.

polygon_from_extent: Turn an extent object into a polygon

Description

Usage

Arguments

Value