sMap

Basemap Generation

The apollo interactive traverse map takes advantage of several different data sets to include base maps at several different resolutions.  The lowest resolution base maps (60 m/pixel) used for missions 11, 12, 14, 16, and 17 are subsets of the Lunar Orbiter (LO) image mosaic which can be downloaded from the US Geological Survey (USGS) Map-a-Planet website (http://www.mapaplanet.org/explorer/moon.html).  The lowest resolution (15 m/pixel) base map used for mission 15 is a mosaic of ortho images from the Apollo panoramic camera processed by the USGS.  Higher resolution images used include a panoramic image from Apollo 17 at ~4.4 m/pixel resolution, and recently acquired uncalibrated Lunar Reconnaissance Orbiter (LROC) Narrow Angle Camera (NAC) images at 1-2 m/pixel acquired over sites 11, 12, 14, 15, 16, and 17.  LROC images can be downloaded from Arizona State University.

All of the local maps were registered to the "low-resolution" maps (i.e. LO and a15 panoramic mosaics) by rubber sheeting method. All the data are in simple cylindrical projection centered at zero longitude, because the LO image mosaics downloaded from USGS use this reference system. The accuracy of the basemaps may be improved once a better version of the image data is available.

Traverse Generation

Traverses for Apollo 12 and 14 were determined by tracing tracks made by the astronauts and the Modular Equipment Transporter visible in LROC NAC images.  Where tracks were not visible the traverse was completed by comparison with published traverse sketches.  Apollo 11 does not include a traverse. The traverse path of the Apollo 15, 16, and 17 Lunar Roving Vehicle was generated from navigation bearing and range measurements made by Apollo astronauts at rover stops on the lunar surface. All traverse measurements are relative to the Lunar Module (LM).  Traverse data were taken from the NASA Technical Note [1].   The following gives an example on how the Apollo 16 traverse was calculated.

Assuming the position of the LM is (X0, Y0), the coordinates of each position (Xi, Yi) in the local Apollo 16 landing site coordinate system are calculated from the following equations.

Xi = X0 - Range * sin (α)

Yi = Y0 - Range * cos (α)

Where

(X0, Y0) is the LM position, (0.0, 0.0) meters

Range is the navigation range in meters, measured with respect to the LM

α is the navigation bearing in radians, measured with respect to the LM

The traverse is generated in shape format from all calculated rover positions . For the Apollo 16 mission, when we compared the calculated traverse with the plots in NASA Technical Note [1] and the map from DMATC [2], two records were dropped from the table because of the inaccuracy of the data (see PDS_Apollo16_AN_Oct23_08.ppt).

Since the calculated traverses were all in the local coordinate system, the final traverses were transformed to the same global coordinate system as the LO image mosaic referenced, and draped on the top of the basemap layers.

Features and Sample Locations

Features and sample locations where determined by overlaying sketch maps generated by the USGS and found in the Preliminary Science reports over the basemaps.  The locations are approximate.

References

1 Smith, E.C. and W.C. Mastin, Lunar Roving Vehicle Navigation System Performance Review, NASA Technical Note NASA TN D-7469, November 1973, pp. 28-55. PDF document courtesy NASA Technical Reports Server (http://ntrs.nasa.gov/).

2 Map of Apollo 11, 12, and 14 Traverses, The Defense Mapping Agency for the National Aeronautics and Space Administration, Greenbelt, Maryland, USA. Url: http://www.lpi.usra.edu/resources/mapcatalog/LPST/ap_11_12_14/.

3 Map of Apollo 15 Traverses, The Defense Mapping Agency Topographic Center (DMATC), Washington D.C., USA, April 1975. Url: http://www.lpi.usra.edu/resources/mapcatalog/LPST/41b4s4/.

4 Map of Apollo 16 Traverses, The Defense Mapping Agency Topographic Center (DMATC), Washington D.C., USA, March 1975. Url: http://www.lpi.usra.edu/resources/mapcatalog/LPST/78d2s2/.

5 Map of Apollo 17 Traverses, The Defense Mapping Agency Topographic Center (DMATC), Washington D.C., USA, March 1975. Url: http://www.lpi.usra.edu/resources/mapcatalog/LPST/43d1s2.