Improvements to altimetry analysis and plotting

[bpurinton]

• Better selection of ICESat tracks for pc_align (and validation). Use DEM timestamp to select:
  • closest in time
  • ~90 day padding
  • all time
  • seasonal
  • Spawn all four, see if they agree and provide similar translations
• Improve profile plotting:
  • before and after plots from pc_align
  • add ATL03 photons
  • use mix of markers for altimetry and lines for DEM (continuous surface)
  • separate ground and top of canopy and plot both
  • How to select profiles for plotting? Interactive? Closest in time? Most points left after filtering?
    • use dh map to find best and worst agreement (worst = 90th percentile or so); do show the minimum (best)
    • group by spot + track + cycle to get unique profiles; look at stats of those; perhaps filter points more with that information
    • plot longest track
• Incorporate GEDI