GIS for Planetary Geologic Mapping

1. GIS for Planetary Geologic Mapping Tools and methods to get started using GIS geologic mapping Prepared for a NASA PGM 1 day workshop USGS Astrogeology GIS for Planetary Geologic Mappers

2. Introduction • Goals • Orient planetary mappers to the GIS functions and utility • Define format for future workshops • Ultimately, assist in map submission, review, and production • Format • Workshop introduction • Arc environment (“Just get me started…”) • Global datasets • Map projections (over lunch) • Introduction to digitizing tools and techniques • Polygon construction • Follow-up (time permitting) GIS for Planetary Geologic Mappers

3. Some important notes • USGS Astrogeology primarily uses only one “brand” of GIS (ESRI’s ArcMap, levels) • Other brands exist, both free and commercial • “Free” • Quantum GIS (qgis.org/) • UDIG (udig.refractions.net/confluence/display/UDIG/Home) • Open EV (openev.sourceforge.net/) • JUMP (jump-project.org/) • GRASS (grass.itc.it/) • Commercial • TNTmips (www.microimages.com/) • ER Mapper (www.ermapper.com) • PCI GeoMatica (www.pcigeomatics.com) • Global Mapper (www.globalmapper.com) • Integraph (www.intergraph.com) GIS for Planetary Geologic Mappers

4. Some important notes (cont’d) • Though this presentation is geared toward geologic mappers, the information is relevant to all GIS users • Screen-shots are likely to differ from individual views • GIS skills are developed through software interaction … be patient and try new things!  Tip icon will point out helpful hints throughout the presentation GIS for Planetary Geologic Mappers

5. GIS Support • ESRI online portal to technical information • http://support.esri.com • ESRI ArcScripts • http://arcscripts.esri.com/ • ESRI Educational Services • Instructor-led training • Virtual Campus courses • Web workshops • Books GIS for Planetary Geologic Mappers

6. GIS Support Nodes • Planet-specific information (e.g., data, discussion, tutorials) • http://webgis.wr.usgs.gov/ • USGS discussion board (login required) • http://isis.astrogeology.usgs.gov/ … navigate to “Support”  “Planetary GIS Discussions” “Plugging keywords into a internet search engine is a great way to search for GIS-related assistance!” GIS for Planetary Geologic Mappers

7. Transition GIS for Planetary Geologic Mappers

8. Arc Environment“Just get me started…” • Introduce ArcMap & ArcCatalog interfaces • Create a FILE Geodatabase (GDB) • Add attributes (domains) • Build a feature dataset and add three features (contacts, structures, units) • Import map bases (raster data) • Edit the features by adding lines and points (vector data) GIS for Planetary Geologic Mappers

9. GIS - “The horror…the horror….” • Organization!! • Multi-layer display • Digitize and edit on-the-fly • “Easily” generate layouts/figures (Adobe Illustrator compatible) • Raster and vector analysis • Crater counts • Spectral statistics for mapped units • Endless possibilities • Editing • Set rules for validating data • Easily edit/modify existing linework GIS for Planetary Geologic Mappers

10. ArcCatalog – your friend • Separate entity from ArcMap • Interface is similar to WindowsExplorer • Create new file • Add/Delete folders or files (if unlocked) • Good operating environment for ArcToolbox • Almost always running in background • ArcMap is opened and closed routinely GIS for Planetary Geologic Mappers

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13. “Geodatabase” ? • ESRI FILE Geodatabase • Contains diverse spatial information • Vector, raster, tables • Topology, toolboxes, domains • Easily transferable to colleagues • Easily organized and managed • Stable GIS for Planetary Geologic Mappers

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16. Geodatabase – General Info Tab GIS for Planetary Geologic Mappers

17. Geodatabase – Domains Info Tab “There is a difference between an attribute domain (described above) and a spatial domain (described later). Use the Arc Help search to see if you can distinguish this important difference” GIS for Planetary Geologic Mappers

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22. Generate Feature Dataset • Geodatabase set • Domains set • Contacts • Structure • Temporary unit names • Next…Create a group of affiliated spatial information…a dataset of features (Polygons, lines, points) GIS for Planetary Geologic Mappers

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27. Specify Geometry Specify “Text” (vs. number, etc.) Add “TYPE” Specify DOMAIN GIS for Planetary Geologic Mappers

28. Three feature classes using three specified attribute domains GIS for Planetary Geologic Mappers

29. Open existing ArcMap project • Good to have multiple projects (~backups) • Easily transferable to colleagues with GDB • Organizational preferences abound • Start ArcMap  Select: • New empty map • A template • An existing map GIS for Planetary Geologic Mappers

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31. Transition • Pre-loaded GIS • Add and move data • View properties • Attributes • Domains • Raster/vector • Menus GIS for Planetary Geologic Mappers

32. Transition • Projections GIS for Planetary Geologic Mappers

33. Map projections • Define the spatial relationship between locations on earth and their relative locations on a flat map • Are mathematical expressions • Cause the distortion of one or more map properties (scale, distance, direction, shape) GIS for Planetary Geologic Mappers

34. Classification of map projections • Conformal – local shapes are preserved • Equal-Area – areas are preserved • Equidistant – distance from a single location to all other locations are preserved • Azimuthal – directions from a single location to all other locations are preserved GIS for Planetary Geologic Mappers

35. Classification of map projections • Another classification system • By the geometric surface that the sphere is projected on • Planar • Cylindrical • Conic GIS for Planetary Geologic Mappers

36. Planar surface Earth intersects the plane on a small circle. All points on circle have no scale distortion. GIS for Planetary Geologic Mappers

37. Classifications of Map Projections Cylindrical surface Earth intersects the cylinder on two small circles. All points along both circles have no scale distortion. GIS for Planetary Geologic Mappers

38. Classifications of Map Projections Conic surface Earth intersects the cone at two circles. all points along both circles have no scale distortion. GIS for Planetary Geologic Mappers

39. Planetary Projections • The following slides cover: • Standard planetary projections • Geographic vs. Geocentric Issues • Positive East vs. Positive West • Setting planetary bodies in ArcMap • Defining a projection using the planetary body • Projecting vector datasets • Projecting raster datasets GIS for Planetary Geologic Mappers

40. Standard projections • Standard projections in planetary • Simple Cylindrical (Equidistance Cylindrical, Equirectangular) • rectangular global (decimal degrees or meters), simple “database” projection. • Sinusoidal • Used for global and many tiled data releases, equal area projection. • Mercator • Conformal, only use for equatorial areas, used in the Mars 1:5M series. • Transverse Mercator • Good for local areas “large” scale maps. A Small scale map shows more land area, but with smaller representations and, therefore, lesser detail. GIS for Planetary Geologic Mappers

41. Standard projections – cont’d • Standard projections in planetary • Polar Stereographic • Good for polar, error increases away from central latitude (usually 90 or -90). Scale should be based on polar radius, can use polar radius. • Lambert Conformal • Good for mid latitudes. Error increases away from both standard parallels. • Orthographic • Globe view, not good for mapping as the limb falls away, makes for pretty figures but you need 3 globes to portray an entire planet. ISIS uses a spherical equation • Mollweide • Coming of age projection, global GIS for Planetary Geologic Mappers

42. Standard projections – cont’d • Other projections in planetary • Lambert Azmuithal • Good for mid latitude and polar, equal area, VICAR/HRSC team uses it for polar areas. • Robinson • Good for figures (similar to Mollweide) GIS for Planetary Geologic Mappers

43. Geographic – Geocentric Issues • Planetographic vs Planetocentric - issues • Mars is the only problem • Most commercial commonly don’t use ocentric - ArcMap does • Work around … use sphere definition for Mars. • For commercial applications, don’t use elliptical definitions and ocentric latitudes. Using elliptical and ographic is okay. The one caveat is Polar Stereographic. GIS for Planetary Geologic Mappers

44. East-West Longitude • Positive East vs. Positive West • Not much to say because commercial GIS/RS systems use positive East. You should always save your files using positive East. • To use West, you either fake out the system (by using your own code) or you switch software. It is just a shift, so no errors are incurred. • Luckily, if you are working in meters there is no East/West system, only Cartesian. GIS for Planetary Geologic Mappers

45. Setting Projections in Arc • Use toolbox or ArcCatalog to set datasets projection • Toolbox: • ArcCatalog (data properties) • For many files, under toolbox samples there is a batch define projection GIS for Planetary Geologic Mappers

46. Setting Projections in Arc • Setting planetary bodies in ArcMap • Example for decimal degree (lat/lon) ArcMap dataframe or for most vector datasets on the data DVD. • (“Coordinate Systems\Geographic Coordinate Systems\Solar System\Mars 2000.prj”) • Select this body definition from the Geographic, Solar System folder shown on the right. GIS for Planetary Geologic Mappers

47. Setting Projections in Arc • Example for the ArcMap dataframe or for MOLA and most raster datasets on the data DVD. • To define a new projection click on New, “Projected” GIS for Planetary Geologic Mappers

48. Setting Projections in Arc • Mars Polar projection • Note the “D_Mars_2000_Sphere_Polar” definition. GIS for Planetary Geologic Mappers

49. Setting Projections in Arc • Projecting datasets using toolbox Projecting vector Projecting raster datasets GIS for Planetary Geologic Mappers

50. Transition • Editing GIS for Planetary Geologic Mappers