Geologic Map of the Elysium Paleolake Basin, Mars
May 5, 2018

The original geologic map was created in 1995 from Viking Orbiter imagery. To make this map more useful with modern data it has been georeferenced to align with the more modern 2014 THEMIS Daytime IR imagery. Links used to transform the data are included with this documentation. A polyline feature class was created to digitize contacts at 1:800k, and attributed with contact type. A polygon feature class was created from this polyline feature class, attributed with geologic unit labels, and symbolized based on RGB values identified from the map sheet TIFF in Adobe Photoshop.

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Data are saved in a feature dataset in I2397_Elysium_Paleolake_Basin_5M.gdb

I2397_Elysium_Paleolake_Basin_5M.gdb_GeoContacts (polyline feature class)
I2397_Elysium_Paleolake_Basin_5M.gdb_GeoUnits (polygon feature class)

GCS_Mars_2000_Sphere
Projection    	Mercater

Zunits        NO                                                                
Units         METERS                                                            
Xshift        0.0000000000                                                      
Yshift        0.0000000000                                                      
Parameters 3396190.0000000000  3396190.0000000000                               
-170.00000 /* longitude of central meridian                                   
0.000 /* latitude of true scale                                          
0.00000 /* false easting (meters)                                       
0.00000 /* false northing (meters)

Separate shapefiles of the two feature classes are located in the ...Data/Shapefiles/ directory.

The coordinate system used for this digitization is based on the coordinate system stated on the map sheet and is stored in ...Documentation/CoordinateSystems/ directory.

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Basemaps have not been included in this download package, but the most current base using THEMIS data is available through ArcGIS Online or can be downloaded at the following link:
https://astrogeology.usgs.gov/search/map/Mars/Odyssey/THEMIS-IR-Mosaic-ASU/Mars_MO_THEMIS-IR-Day_mosaic_global_100m_v12

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Below are the RGB values sampled from the scanned map sheet used to symbolize geologic units and saved as a layer (*.lyr) file in the ...Data/LayerFiles/ directory. 

GeoUnit		      RGB
Aebk      106  191  218
Aebb      221  247  243
Aebe      210  219  241
Ach       98   132  184
Hch       131  179  227
Hchp      188  235  255
Hcht      132  174  173
Amu       185  225  216
Amm       206  226  151
Aml       131  158  124
Aps       240  205  132
Aa1       255  236  225
Hr        211  163  196
Ael2      247  142  139
Hel1      255  180  176 
Ha4       255  204  200
Ha3       255  148  80
Ha2       248  135  122
Ha1       226  115  89
Hpl3      253  233  121
Npld      219  135  100
Npl1      250  173  97
Nplh      216  189  147
HNu       202  119  160
Ac        253  255  110
AHc       203  195  138
Nc        196  136  118
           
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For more information, contact:
Michelle Barton
mbarton@usgs.gov
USGS Astrogeology Science Center
Flagstaff, AZ
(928)556-7177