Digital Preservation and Formats from the US Library of Congress

The Digital Formats and Preservation web site from the US Library of Congress provides information about digital content formats and related items.  As the name implies, the site was created to support strategic planning to ensure the long term preservation and management of digital content.  This is particularly important in our day and age when data formats and types are rapidly changing.  The site was established in 2004 but seems to be updated regularly based on the date stamp on the pages and also judging from the content.  

The GIS section of this site provides information about geospatial resources, formats, quality, and functionality.  International Standards Organizations documents supporting the creation and maintenance of GIS metadata are referenced; in fact, everything is provided with key references.  As we advocate in our book:  Check your sources.  Here, the source was the University of California at Santa Barbara libraries as part of the National Geospatial Digital Archive Project.

Digital Preservation GIS site.

I am pleasantly surprised by this site. It is not overly wordy, but provides a great deal of key information about GIS in a short amount of space.  I should have expected as much from some top-notch librarians who undoubtedly were behind this effort.  It doesn’t waste time with images–we are talking no-nonsense text here.  Information includes data types, and definitions of accuracy, precision, map scale, datum, projections, and coordinates.  Spatial analysis,   Of interest as well are the format descriptions for geospatial data, helping the user navigate the acronym maze such as NetCDF, SDTS, TIFF, and more.  The site thus reads somewhat like a mini-GIS fact book.

The major drawback to the site is that some of it, particularly the papers and presentations that are referenced, are 5 or more years old.  I recommend that the next project for those maintaining the site is the improvement server-GIS and web-GIS terms and data formats.  Still, it is a good supplement to our The GIS Guide to Public Domain Data book.

WorldPop – Population distribution data

Last year we blogged about the AsiaPop and AfriPop projects that had been established to produce detailed and freely available population distribution maps for Asia and Africa. Last month the WorldPop project was launched, combining the AfriPop, AsisPop and AmeriPop population mapping projects into ‘a single open access archive of spatial demographic data for Central & South America, Africa and Asia for development and health application‘.

 The following free datasets can be downloaded (as a zipped GeoTiff file) from the WorldPop site:

– Population distribution datasets for African and Asian countries
– Age/sex structured population distribution datasets for Africa 2000-2015
– New 2000-2010 Asia population distribution datasets incorporating satellite-derived urban growth maps
– Births/pregnancies distribution datasets for eleven countries
– Multidimensional and consumption-based poverty rate datasets for five countries

WorldPop poverty data

Metadata is provided with each data download and for those interested in finding out about how the data were  produced, the methodological details are available on the WorldPop website. In the coming months additional datasets will be made available including:

– Population distribution datasets for Central & South America
– Age/sex structured datasets for Central & South America and Asia
– Births/pregnancies datasets for 75 countries
– Multiple updates on existing population rate datasets through new input data and methods

 

Listing of Free GIS Data Sources from Robin Wilson

As we discuss in the book The GIS Guide to Public Domain Data, listings of spatial data sources have existed since the dawn of the web.  Those of you who have been around GIS as long as I have might remember such lists as the Oddens Bookmarks, which already contained over 5,500 categorized references by 1998, and the Alexandria Digital Library Project from UCSB.  The objective of these lists has always been, if not to eliminate, to at least reduce the need for each of us in the field to maintain our own lists.  While Internet search engines have vastly improved over the past 20 years, listings still have their place and are still useful, because search engines do not always pick up the relevant data and tools that the geospatial community is seeking.

With the crowdsourcing tools available to us nowadays, though, is it not possible for someone or an organization to create a crowdsourced listing of geospatial data?  To maximize the utility of such a resource would require someone vetting the list to make certain that only relevant items are approved.  Perhaps a reader can comment on this post to let the community know if such a project exists or is in the works.

In the spirit of being helpful to the geospatial community, Robin Wilson, PhD student at the University of Southampton, created the resource “Free GIS Data” on http://freegisdata.rtwilson.com/.  Robin’s index is one of the more useful I have seen and is frequently updated.  It contains over 300 sources with headings of physical geography, cultural geography, as well as data about specific places.  One of the most helpful things about the resource is Robin’s brief but very useful 1-2 sentences about each resource, which serves as a useful bit of metadata to guide the user.

GIS Resource Listing by Robin Wilson.

One of the drawbacks of resources like this and other well-intentioned lists from graduate students is longevity.   Will the site be there in the future when Robin graduates?  I hope so.  Still, for now, this is a very useful resource.  Thank you Robin!

Google’s public data program

A recent, rather low-key, announcement from Google reported the launch of their new public data program. As part of the Google Maps Engine project, which allows users to create custom maps online, the public data program aims to make public data more discoverable by allowing users to (optionally) publish their data through Google. The published data will be added to the content that may be searched via other Google tools such as  Google Maps, Google Maps Gallery and Google Earth.

Google Maps Engine

The public data publishing service is free, users retain ownership of their data, which may be removed at any time, and user restrictions or end user licensing conditions may be attached to the content. The goal is to help ‘authoritative publishers to overlay their content on top of Google’s base map and make it accessible and useful’. By authoritative publishers Google means public data providers and governments who capture and maintain data that is of public interest and who wish to make that data available as a public good. Some examples of the type of mapping content Google are interested in publishing include:

• Crisis and emergency management data
• Statistics ( elections, demographics, health)
• Government (administrative boundaries, local services, transport)

Given the prevalence of Google’s existing mapping interfaces, the public data program seems set to take advantage of Google’s already strong presence in the online mapping market. It will be interesting to see how much more public data are published.