The North American Carbon Program Google Earth Collection
Peter C. Griffith, NACP Coordinator; Lisa E. Wilcox; Amy L. Morrell, NACP Web Group
Organization: Science Systems & Applications, Inc. and the Carbon Cycle and Ecosystems Office, NASA Goddard Space Flight Center
Summary
The central objective of the North American Carbon Program (NACP), a core element of
the US Climate Change Science Program, is to quantify the sources and sinks of carbon
dioxide, carbon monoxide, and methane in North America and adjacent ocean regions.
The NACP consists of a wide range of investigators at universities and federal research
centers. Although many of these investigators have worked together in the past, many
have had few prior interactions and may not know of similar work within knowledge
domains, much less across the diversity of environments and scientific approaches in the
Program.
Coordinating interactions and sharing data are major challenges in conducting NACP.
The Google Earth Collection on the NACP website (www.nacarbon.org) provides a
geographical view of the research products contributed by each core and affiliated NACP
project. Other relevant data sources (e.g. AERONET) can also be browsed in spatial
context with NACP contributions. Each contribution links to project-oriented metadata, or
project profiles, that provide a greater understanding of the scientific and social context
of each dataset and are an important means of communicating within the NACP and to
the larger carbon cycle science community. Project profiles store information such as a
project's title, leaders, participants, an abstract, keywords, funding agencies, associated
intensive field campaigns, expected data products, data needs, publications, and URLs to
associated data centers, datasets, and metadata. Data products are research
contributions that include biometric inventories, flux tower estimates, remote sensing land
cover products, tools, services, and model inputs / outputs.
Project leaders have been asked to identify these contributions to the site level whenever
possible, either through simple latitude/longitude pair, or by uploading a KML, KMZ, or
shape file. After post-processing, research contributions are added to the NACP Google
Earth Collection to facilitate discovery and use in synthesis activities of the Program.
Process for Generating Profile KML files for Google
Earth:
Collecting Coordinates: When NACP Project Leads update their
project profiles using an online tool, they may provide site level
coordinates for their data contributions by entering
latitude/longitude values or by uploading their own KML, KMZ, or
shape file. Coordinates are parsed from the KML or KMZ file
(specifically from the
tag) using the XML::Simple Perl CPAN module.
We check that the coordinates are valid for North America using a
series of Perl regular expressions, and then if valid, they are stored
with each data contribution in a MySQL database.
Project Lead submits
project profile content and
identifies data contributions
to the site level (coordinates).
start
Store coordinates with data
contributions in MySQL database.
If KML/KMZ file uploaded,
parse coordinates using
XML::Simple Perl CPAN module.
No
Valid
Coordinates?
Yes
KML files with placemarks
and KML files with
Network Links for
each Data Contribution.
MySQL
Database
and
Web Server
NACP Coordinator
works with
Project Lead
View NACP Data
Contribution
Collection KML in
Google Earth
Perl scripts generate
KML / XML files when
profile data is updated
P
e
r
XML files with marker
l
tags for each Projects
Data Contributions.
Use Perl and Google Maps API to
parse each XML file and display
markers for each projects data
contributions on a Google Map.
Project profiles and data can also be discovered via
Google Map from the NACP website
Generating KML File: When a data contribution is updated, a Perl
script automatically queries the MySQL database and regenerates
the KML file of tags for that data contribution. We
customize the content and layout of the Google Earth Info-Window
by defining a item in conjunction with
name/value pairs.
The Google Map provides a spatial data discovery of
research contributions integrated directly within the NACP
website. We use Perl CPAN modules (CGI, DBI, and
Text::Template) to generate up-to-date XML files of data
contributions for each NACP Project. We then use
Javascript code with the Google Map API GDownloadUrl
method and the GXml.parse method to read & parse each
XML file. Looping through the XML, we use the
createMarker Google Maps API function to create each
marker, with location, name and info-window content to
display on the Google Map. Users can click on each
marker and follow links to view that NACP Projects
detailed profile.
Using Network Links to Share the KML: We generate a
separate KML file containing a network link to each of the individual
data contribution placemark KML files. The KML file with network
links is hosted online. The KML includes the attribution
data tags defined in the W3C Atom Syndication Format
namespace so that it can be indexed correctly by Google and
other web crawlers. The NACP Google Earth collection KML is
comprised of the comprehensive list of all of the NACP network link
KML files, so that once a user loads the collection KML into their
local Google Earth, any new changes to the profile will be reflected
in that users Google Earth.
Whats next in the Google Map Application?
Challenges to address:
Better integration into website - plan to display the project
profile in a frame below the map when a user selects a
marker.
How to represent regions and continental modeling
efforts on the Google Map?
Can Google Map expand markers when more than one
marker is in the same location?
Add side menu searches to toggle markers appearing on
the map based on selected search criteria.
Whats Next for the Google Earth Collection?
use different placemark icons to represent specific data collection
types/categories (what categories would be useful for NACP
collection)
display regional / continental scale data contributions / modelling
products (not just site-level placemarks)
use Google Earth API to more closely integrate Earth in to NACP
website and add custom searches and user friendly interface.
Acknowledgement: The generous support
given to us by NASAs Terrestrial Ecology Program.
Contact: Peter Griffith, NACP Coordinator, [email protected]
