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C-squares concept: Data items are represented by the grid squares in which they are located 1: Data items2: Data items and relevant grid squares 3: Grid.

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Presentation on theme: "C-squares concept: Data items are represented by the grid squares in which they are located 1: Data items2: Data items and relevant grid squares 3: Grid."— Presentation transcript:

1 C-squares concept: Data items are represented by the grid squares in which they are located 1: Data items2: Data items and relevant grid squares 3: Grid squares alone

2 Principal purpose of c-squares is for spatial indexing and spatial queries - secondary application is for mapping - another is for data aggregation, e.g. for analysis, reporting, exchange - can also be efficient: e.g. in OBIS case, map <2,000 squares rather than 50,000 data points for one species (over 95% faster) - or, map 70,000 squares rather than 9 million points (all the data...) OBIS data – “all vertebrates” (3.4 million records)...

3  First c-squares mapper constructed at CMAR, Hobart in early 2002 – used by CMAR applications, OBIS, FishBase and Cephbase  Mapper upgraded (v2) in 2003 – to map multiple sets of squares concurrently, and support “click on map” functionality (e.g. to do a “get the data” query)  Minor upgrades in 2004/5 to suit needs of AquaMaps project, also ported to faster machine at CMAR, Hobart (20x speed increase...)  Mapper installation replicated at IfM- GEOMAR (Germany), and Swedish Museum of Natural History, in 2005/6, for FishBase/AquaMaps and INCOFISH project use

4  Jan-May 2006: Mapper upgraded (v3) to use more detailed graphics (supporting seamless pan and zoom across the entire world), better seabed detail, more realistic land images  New “globe views” introduced (with new graphical user interface to spin the globe around), based on Hari Nair’s “Xplanet” software  Squares can be enhanced for extra visibility (“bold” or “intermediate”), or plotted at fine scale as desired  Land masking is available on globe views and all derived maps  Gridlines have been added to maps based on “globe views” to help user orientation  Maps based on globe views have more “correct” representation of proportion when zoomed in, also supports polar views (ideal for plotting Arctic, Antarctic data)  Quite a bit of background optimization to minimise redraw wait times, etc. once globe views have been created.

5 New “world” base maps...

6 Improved land and seabed resolution for all areas...

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9 Globe views available from all “world” maps – continuously tiltable and rotateable

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23 Ability to view polar regions – with / without ice cover, as preferred

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26 Land mask available for all new maps Land mask off (all current OBIS fish data) Land mask on

27 Three ways to try out the new features:  Via any OBIS species page, or “group” clickable map  Direct call to mapper with a suitable c-square code or codes, e.g. http://www.obis.org.au/cgi-bin/ cs_map.pl?csq=1000 http://www.obis.org.au/cgi-bin/ cs_map.pl?csq=1000  Via mapper entry page on obis.org.au (follow link “tools”) credits: Mapper development: Tony Rees, Miroslaw Ryba, Philip Bohm (CMAR) Xplanet (globe rendering): Hari Nair, JPL (via SourceForge)


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