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Online Geological Mapping

Finding geological mapping is tricky at the best of times.  Finding it online?  For free?  Well, it can be done, for some places at least.

Geological Map of Spain - Extract

Geological Surveys around the world take very different stances on making their data available.  Some have a legal requirement to make their data available freely and as widely as possible, while others have to treat their data as a state secret and not even acknowledge its existence.  Further complications arise because access to the infrastructure of the Internet cannot be taken for granted in some places while other surveys simply do not have a budget and exist in name only, others must turn a profit to keep in business.

What would be really useful in the first place is if someone, somewhere compiled a list of surveys and other geosciences organisations around the world that produce mapping data as well as other geological data.  Luckily someone has already done that and put the list online.

Take a bow the Geological Survey of Japan.  Their Directory of Geoscience Organizations of the World is updated roughly every 12 months and has contact details for just about every state-based surveying organisation in the world.  There are some errors in the list and URLs do change quickly and without notice, but this is probably the best starting point out there for finding what’s available online.

Geological Map of Liberia - Extract

Another useful resource is the United States Geological Survey (USGS).  Not only are they responsible for the geological maps of the USA, they’ve also mapped other countries.   There are two main problems with using the USGS website (www.usgs.gov).  The first is that it’s so large and unwieldy, it can be hard to find what you’re looking for.   To help a little bit, here’s a link to USGS publication store.  As you might imagine they’re quite keen to sell you copies of the maps and texts.  However nearly all of the maps are available freely online and as PDF documents if you know how to navigate their labyrinth of hypertext.  Just to show that it can be done, here’s the 1:250,000 sheet for Buchanan, Liberia published by the USGS in 1977.  I’ll be writing a page on exactly how to navigate the USGS website soon.  Watch this space.

Geological Map of Canada - ExtractNatural Resources Canada have many thematic maps available online through their GeoGratis resource.  You can search their collection using a rather flashy, if clunky GIS interface, or a simple form if you prefer.  All maps are available in PDF and JPEG formats as this map of Schultz Lake, Nunavut shows.  There are also some GIS products available in ESRI Shapefile (SHP) and GML formats.  The Canadians have historically published maps at a variety of scales and themes bundled together in one long series of mapping.  There is no ‘grid’ available showing coverage as there is for such series such as the British Geological Survey’s 1:50,000 series.  To find out what’s available you will have to use the GIS interface.

You’ll notice that both the USA and Canada offer many other downloads besides maps.  There is a range of datasets and other publications available freely as well.

Geological Map of Mexico - ExtractIGME in Spain has recently made details JPEG scans of their entire 1:50,000 series coverage available on their website, as well as coverage at smaller scales.   Over at the SGM in Mexico, there is similar coverage available freely online, although Mexico is has only got approximately 40% coverage at 1:50,000, there is a very good 1:250,000 set available.  All of these available as PDF files from SGM.

You’ll notice that if you’re not able to read Spanish, navigating these websites can become problematic.  I recommend using Google’s Chrome browser to do so.  If you have it set up with English as your default language, it will normally offer to translate any page it detects is in a foreign language using Google’s Translate tool.  The results are not perfect, but make navigating sites in pretty much any foreign language much easier, including Mandarin Chinese, Japanese, Arabic, Hindi and Russian.

At Geoscience Australia, they have made available JPEG scans of their entire 1:250,000 coverage of Australia as well as some coverage at smaller scales and with different themes

Ingemmet in Peru have the entire country mapped at 1:100,000 and a decent chunk at 1:50,000 and available as scanned JPEG online.

Geobank in Brazil have the entire country available as zipped PDFs available at 1:1,000,000 with several State maps at better scales.

Of course the British Geological Survey have made a lot of mapping available through OpenGeoscience, including the 1:50,000 series available using their Geology of Britain viewer.

More and more mapping is appearing on the Internet all the time, so much that it’s difficult to keep up with it all.  This page should develop into a country-by-country set of pages giving guides as to what's available and from where.  Please keep checking back.

If you know of any freely available online mapping that I haven’t yet covered, please let me know by contacting me at paul.johnson@geolsoc.org.uk