• GPR can produce amplitude-slice maps of large grids of data very quickly, and these can be used to plan excavations, or define areas for more detailed surveys.
• If the velocity of radar energy in the ground is calculated, a series of slices can produce a three-dimensional picture of a site in true depth.

Figure 18

• Analysis of individual reflection profiles within grids give a more detailed two-dimensional picture.  Excavations can then be placed directly on features visible in profile.

• Video images that show changes in amplitude with depth are particularly helpful in finding some features, which may not be immediately visible in profiles or amplitude slice-maps of larger sections of the ground.

Figure 23

• Once maps are made of a site, and areas of importance are delineated, it is important to re-collect high definition data in smaller grids. 

Figure 40

• High definition data can not only produce images of buried architecture with more accuracy, but the individual profiles reveal subtle stratigraphy that can also be important.

Figure 25

• Data should always be processed to remove background noise and high angle tails of reflections hyperbolas to produce more accurate reflection profiles of buried features.

Figure 29

• When processed reflection profiles are used to produce amplitude time-slices, the resulting three-dimensional maps are a much more accurate representation of the subsurface.

Figure31

• Our work at Petra shows how GPR mapping can quickly and accurately make maps of large areas of a site.   In addition, subsequent excavations are always necessary to confirm GPR results.  
• The correlation of GPR reflections to excavated subsurface features is necessary in order to project information into un-excavated portions of a site.

• In the future we envision using GPR mapping for:
  • Initial site reconnaissance
  • A guide for placement of excavations in the most promising, or important areas
  • The production of high resolution images of features that may never be excavated
  • Creating three-dimensional rendered images and maps of large buried sites, with a minimal amount of excavation
• As with any scientific endeavor, our GPR work at Petra has allowed us to ask even more questions than were considered in the initial research plan:
  • For the future we are planning additional excavations to test many other features that have been mapped by GPR.
  • A number of other potentially important structures have been found in the "Lower Market," whose age and function can only be postulated without further excavations.
  • Buried soil horizons from what appear to be ancient gardens have been found and mapped spatially.  Smaller features associated with those gardens must now be excavated to better understand the function of this site over time.
  • Additional GPR surveys will be conducted using higher resolution antennas, to produce even more detailed images of the subsurface.