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HGA Components

Four or five separate Back-end Services (shared code repository?):

(Multiple Harmony services are possible with different chaining)

  • Single-Variable Extractor - Multi-Variable Front-End - output to GeoTIFF, or VRT (for chaining)
    • Variable Subsetting (GDAL Translate)
  • HGF - Harmony GDAL Formatter (GDAL Translate)
    • Various single variable formats as outputs
    • Grid and/or Trajectory/Vector/Shape
    • Single-Var in, single var out
      (But note Multi-Variable Front-End enables e.g., HDF5 & NetCDF to GeoTIFF/COG)
    • COG default for TIFF/GeoTIFF
  • Browse-Image Extractor (BIE? - TRT-213, GdalDEM?)
    • Image Generator - color maps
    • gdaldem - color_relief processing
    • Other gdaldem features?
  • HGA - Harmony GDAL Adapter (GDAL-Translate, GdalWarp)
    • Spatial Subsetting, Reprojection
    • GeoTIFF/COG output
    • GeoTIFF/VRT inputs - use single-var extractor to get GeoTIFF/VRT as inputs to HGA
  • HG-Agg - Harmony GeoTIFF Aggregator / NetCDF formatter
    • TRT-51 ?
    • Assuming a prior NetCDF -> GeoTIFF process
    • Multi-GeoTIFF -> NetCDF aggregation
    • Optional NetCDF source can be used for full attribute & metadata copy
    • Has logic for proper CF attribution following reprojection
    • Surprising number of existing code-base examples, including HGA itself
      (Trajectory Subsetter for SMAP - GeoTIFF-to-Netcdf)

Roadmap -

  • build a generalized HGF kernel first, 
  • add the color map and browse-image functionality,
  • purge from HGA and transitioning the end-use community to BIE/HGF.  
  • Split out HG-Agg
  • Then possibly replacing, if necessary, the core HGA implementation, if it is not redeemable.


(early draft):

  • Browse Image Extractor - PNG, PO.DAAC - TRT-213
  • Simple Formatter - Single-Var output - TRT-213?
    • .nc4 or GeoTiff input ?
    • Single Var outputs
    • GeoTIFF / COG - Is this a different use-case than a browse image?
    • ASCII
    • PNG (other image - Browse Image Extractor)
    • KML (KMZ)
    • Any other GDAL option?
  • Harmony Transformation Sampler
    • Swath, Grid inputs - .nc4
    • .nc4 output
      • Re-aggregated from per-variable outputs
        • un-processed Variables copied as-is (with attributes)
        • Geo-tagging variables redefined (included, excluded, added) as required for processed variables.
        • Each var is either: copy, delete, process (read from GeoTIFF), process+
          (process+ is for revised attributes, for revised geo-tagging)
        • Groups, Group-Level & Top-Level attributes copied to output
      • Could/Should be a separate service
    • GeoTIFF in and out is a sub-variant?
      • No re-aggregation
      • Simple GeoTIFF?  Or with color bands and alpha (RGBA)
    • Variable, Spatial (BBox) and Temporal Subsetting
    • With Reprojection - basic Harmony to GDAL parameter mapping
  • Other support - ORNL?
    • LP-DAAC, PO.DAAC, ASF?
    • No requirements have surfaced
  • NSIDC Support:
    • SMAP L1/L2 - Reformat without gridding, .h5 => ascii (CSV), shp, other?
    • SMAP L1/L2 - Reformat after gridding, .h5 => .gtif
    • SMAP L1/L2 - Reprojection (chaining): GeoTIFF/.h5 => Gtif / COG
    • SMAP L1/L2 / L3/L4 - ASCII formats?  GeoTIFF/.h5 => <ASCII>
    • ICESat-2 - ATLAS - L3/L4 (Gridded, mix of projections, grids) -
      • To GeoTIFF / COG - HGA chaining?
    • HDF-EOS-4 legacy data - multiple slightly divergent data products
      • To GeoTIFF / COG - HGA chaining
      • Perhaps .he4 to .nc4 first, and then follow-on processing.
      • Possibly Harmony Transformation Sampler with .he4 inputs


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