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Great Circle h3 cell distances #4

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Great Circle h3 cell distances #4

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e4a8bc5
Great Circle h3 cell distances
cossatot Oct 21, 2025
c7cb795
cleanup
cossatot Oct 21, 2025
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54 changes: 44 additions & 10 deletions src/seismicity/smoothing.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,26 @@ else
end



function gc_distance(lon1, lat1, lon2, lat2)

R = 6371.0

lon1 = deg2rad(lon1)
lat1 = deg2rad(lat1)
lon2 = deg2rad(lon2)
lat2 = deg2rad(lat2)

distance = asin(sqrt(sin((lat1 - lat2) / 2.0)^2.0
+
cos(lat1) * cos(lat2)
* sin((lon1 - lon2) / 2.0)^2.0))

distance * 2.0 * R
end



function smoothing(fname_count::String, fname_config::String, fname_out::String="")

model = TOML.parsefile(fname_config)
Expand Down Expand Up @@ -132,10 +152,15 @@ function smoothing(fname_count::String, smoothing_σs::Array, maxdistkm::Real;
lats = Dict{UInt64,Float32}()
println("Number nodes : ", length(df.h3idx))


dist_lookup = Dict{Tuple{UInt64,UInt64},Float32}()

for tmp in enumerate(zip(df.lon, df.lat, df.count))

cell_lon = tmp[2][1]
cell_lat = tmp[2][2]
# Cell index to whick the current point (i.e. cell center) belongs to
base = geoToH3(GeoCoord(deg2rad(tmp[2][2]), deg2rad(tmp[2][1])), h3res);
base = geoToH3(GeoCoord(deg2rad(cell_lat), deg2rad(cell_lon)), h3res);

# Get the indexes of cells within 'maxdistk' from the cell with index
# equal to 'base'. 'maxdistk' is the distance in terms of the cell
Expand All @@ -152,21 +177,30 @@ function smoothing(fname_count::String, smoothing_σs::Array, maxdistkm::Real;

dsts = zeros(Float32, length(idxs))
for idx in enumerate(idxs)
#println("base: ", base)
#println(typeof(base))
#println("idx[2] ", idx[2])
#println(typeof(idx[2]))
if base == idx[2]
d = Float32(0.0)
else
d = h3Distance(base, idx[2])
if d isa H3ErrorCode
@info "failed: $(base), $(idx[2]). Using default $default_distance"
d = default_distance
v = get(dist_lookup, (base, idx[2]), nothing)
if v !== nothing
d = v
else
# get lon and lat of surrounding bins. Add to lookup dicts if not added yet.
idx_lon = get(lons, idx[2], nothing) # longitude of idx point in lons
idx_lat = get(lats, idx[2], nothing)
if idx_lon == nothing
geo1 = h3ToGeo(idx[2])
idx_lon = rad2deg(geo1.lon)
idx_lat = rad2deg(geo1.lat)
lons[idx[2]] = idx_lon
lats[idx[2]] = idx_lat
end
d = Float32(gc_distance(cell_lon, cell_lat, idx_lon, idx_lat))
dist_lookup[(base, idx[2])] = d
dist_lookup[(idx[2], base)] = d
end

end
dsts[idx[1]] = Float32(d * edge_length)
dsts[idx[1]] = d
if dsts[idx[1]] < 1.0
dsts[idx[1]] = 1.0
end
Expand Down