spMetadata: Methods to generate spatial metadata

In plotKML: Visualization of Spatial and Spatio-Temporal Objects in Google Earth

Methods to generate spatial metadata

Description

The spMetadata function will try to generate missing metadata (bounding box, location info, session info, metadata creator info and similar) for any Spatial* object (from the sp package) or Raster* object (from the raster package). The resulting object of class SpatialMetadata-class can be used e.g. to generate a Layer description documents (<description> tag).
The read.metadata function reads the formatted metadata (.xml), prepared following e.g. the Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata or INSPIRE standard, and converts them to a data frame.

Usage

 
## S4 method for signature 'RasterLayer'
spMetadata(obj, bounds, color, ... )
## S4 method for signature 'Spatial'
spMetadata(obj, xml.file, out.xml.file, 
    md.type = c("FGDC", "INSPIRE")[1],
    generate.missing = TRUE, GoogleGeocode = FALSE,
    signif.digit = 3, colour_scale, color = NULL, bounds,
    legend_names, icons, validate.schema = FALSE, ...)

Arguments

obj	some "Spatial" or "Raster" class object with "data" slot
xml.file	character; optional input XML metadata file
out.xml.file	character; optional output XML metadata file
md.type	character; metadata standard FGDC or INSPIRE
generate.missing	logical; specifies whether to automatically generate missing fields
GoogleGeocode	logical; specifies whether the function should try to use GoogleGeocoding functionality to determine the location name
signif.digit	integer; the default number of significant digits (in the case of rounding)
colour_scale	the color scheme used to visualize this data
color	character; list of colors (rgb()) that can be passed instead of using the pallete
bounds	numeric vector; upper and lower bounds used for visualization
legend_names	character; legend names in the order of bounds
icons	character; file name or URL used for icons (if applicable)
validate.schema	logical; specifies whether to validate the schema using the xmlSchemaValidate
...	additional arguments to be passed e.g. via the metadata.env()

Details

spMetadata tries to locate a metadata file in the working directory (it looks for a metadata file with the same name as the object name). If no .xml file exists, it will load the template xml file available in the system folder (e.g. system.file("FGDC.xml", package="plotKML") or system.file("INSPIRE_ISO19139.xml", package="plotKML")). The FGDC.xml/INSPIRE_ISO19139.xml files contain typical metadata entries with description and examples. For practical purposes, one metadata object in plotKML can be associated with only one variable i.e. one column in the "data" slot (the first column by default). To prepare a metadata xml file following the FGDC standard, consider using e.g. the Tkme software: Another editor for formal metadata, by Peter N. Schweitzer (U.S. Geological Survey). Before commiting the metadata file, try also running a validation test (https://mrdata.usgs.gov/validation/). Before committing the metadata file following the INSPIRE standard, try running the INSPIRE Geoportal Metadata Validator.
spMetadata tries to automatically generate the most usefull information, so that a user can easily find out about the input data and procedures followed to generate the visualization (KML). Typical metadata entries include e.g. (FGDC):

• metadata[["idinfo"]][["native"]] — Session info e.g.: Produced using R version 2.12.2 (2011-02-25) running on Windows 7 x64.

• metadata[["spdoinfo"]][["indspref"]] — Indirect spatial reference estimated using the Google Maps API Web Services.

• metadata[["idinfo"]][["spdom"]][["bounding"]] — Bounding box in the WGS84 geographical coordinates estimated by reprojecting the original bounding box.

and for INSPIRE metadata:

• metadata[["fileIdentifier"]][["CharacterString"]] — Metadata file identifier (not mandatory for INSPIRE-compl.) created by UUIDgenerate from package UUID (version 4 UUID).

• metadata[["dateStamp"]][["Date"]] — Metadata date stamp created using Sys.Date().

• metadata[["identificationInfo"]][["MD_DataIdentification"]] [["extent"]][["EX_Extent"]][["geographicElement"]][["EX_GeographicBoundingBox"]] — Bounding box in the WGS84 geographical coordinates estimated by reprojecting the original bounding box.

By default, plotKML uses the Creative Commons license, but this can be adjusted by setting the Use_Constraints argument.

Author(s)

Tomislav Hengl and Michael Blaschek

References

• The Federal Geographic Data Committee, (2006) FGDC Don't Duck Metadata — A short reference guide for writing quality metadata. Vers. 1, http://www.fgdc.gov/metadata/documents/MetadataQuickGuide.pdf

• Content Standard for Digital Geospatial Metadata (http://www.fgdc.gov/metadata/csdgm/)

• Tkme metadata editor (http://geology.usgs.gov/tools/metadata/tools/doc/tkme.html)

• INSPIRE, INS MD, Commission Regulation (EC) No 1205/2008 of 3 December 2008 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards metadata (Text with EEA relevance). See also Corrigendum to INSPIRE Metadata Regulation.

• INSPIRE, INS MDTG, (2013) INSPIRE Metadata Implementing Rules: Technical Guidelines based on EN ISO 19115 and EN ISO 19119, v1.3

See Also

kml_metadata, SpatialMetadata-class, sp::Spatial, kml_open

Examples

## Not run: 
library(sp)
library(uuid)
library(rjson)
## read metadata from the system file:
x <- read.metadata(system.file("FGDC.xml", package="plotKML"))
str(x)
## generate missing metadata
data(eberg)
coordinates(eberg) <- ~X+Y
proj4string(eberg) <- CRS("+init=epsg:31467")
## no metadata file specified:
eberg.md <- spMetadata(eberg["SNDMHT_A"])
## this generates some metadata automatically e.g.:
xmlRoot(eberg.md@xml)[["eainfo"]][["detailed"]][["attr"]]
## combine with localy prepared metadata file:
eberg.md <- spMetadata(eberg["SNDMHT_A"], 
    xml.file=system.file("eberg.xml", package="plotKML"))
## Additional metadat entries can be added by using e.g.:
eberg.md <- spMetadata(eberg["SNDMHT_A"], 
  md.type="INSPIRE", 
  CI_Citation_title = 'Ebergotzen data set',
  CI_Online_resource_URL = 'http://geomorphometry.org/content/ebergotzen')
## the same using the FGDC template:
eberg.md <- spMetadata(eberg["SNDMHT_A"], 
  Citation_title = 'Ebergotzen data set',
  Citation_URL = 'http://geomorphometry.org/content/ebergotzen')
## Complete list of names:
mdnames <- read.csv(system.file("mdnames.csv", package="plotKML"))
mdnames$field.names
## these can be assigned to the "metadata" environment by using:
metadata.env(CI_Citation_title = 'Ebergotzen data set')
get("CI_Citation_title", metadata)

## write data and metadata to a file:
library(rgdal)
writeOGR(eberg["SNDMHT_A"], "eberg_SAND.shp", ".", "ESRI Shapefile")
saveXML(eberg.md@xml, "eberg_SAND.xml")
## export to SLD format:
metadata2SLD(eberg.md, "eberg.sld")
## plot the layer with the metadata:
kml(eberg, file.name = "eberg_md.kml", colour = SNDMHT_A, metadata = eberg.md, kmz = TRUE)

## End(Not run)

plotKML documentation built on June 7, 2022, 5:07 p.m.