Module: GitFit::Elevation::DemCache

Defined in:
lib/git_fit/elevation/dem_cache.rb

Constant Summary collapse

DEM_CACHE_DIR = 
ENV.fetch('GIT_FIT_DEM_CACHE_DIR', 'data/cache/dem')
CACHE_FILE = 
File.join(DEM_CACHE_DIR, 'dem.json')
GRID = 
0.0003

Class Method Summary collapse

Class Method Details

.grid_key(lat, lng) ⇒ Object 



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# File 'lib/git_fit/elevation/dem_cache.rb', line 14

def grid_key(lat, lng)
  "#{(lat / GRID).round}/#{(lng / GRID).round}"
end

.load_all ⇒ Object 



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# File 'lib/git_fit/elevation/dem_cache.rb', line 18

def load_all
  return {} unless File.exist?(CACHE_FILE)
  JSON.parse(File.read(CACHE_FILE))
rescue StandardError
  {}
end

.load_batch(slice) ⇒ Object 



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# File 'lib/git_fit/elevation/dem_cache.rb', line 25

def load_batch(slice)
  all = load_all
  results = {}
  slice.each do |lat, lng|
    gk = grid_key(lat, lng)
    results[gk] = all[gk] if all.key?(gk)
  end
  results
end

.missing_keys(slice, cached) ⇒ Object 



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# File 'lib/git_fit/elevation/dem_cache.rb', line 35

def missing_keys(slice, cached)
  slice.reject { |lat, lng| cached.key?(grid_key(lat, lng)) }
end

.save_batch(elevs_by_gk) ⇒ Object 



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# File 'lib/git_fit/elevation/dem_cache.rb', line 39

def save_batch(elevs_by_gk)
  return if elevs_by_gk.empty?
  FileUtils.mkdir_p(DEM_CACHE_DIR)
  existing = load_all
  elevs_by_gk.each { |gk, elev| existing[gk] = elev }
  File.write(CACHE_FILE, JSON.generate(existing))
rescue StandardError => e
  warn "DEM cache write error: #{e.message}"
end