Module:Infobox dim: Difference between revisions

Revision as of 04:37, 5 October 2024

Latest revision as of 14:54, 23 April 2025

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local log2 = 0.693147181

local ppm = 1000/0.3 -- pixels per meter, from 0.3 mm / pixel from https://wiki.openstreetmap.org/wiki/Zoom_levels

-- To convert to OSM zoom level, we need to know meters per pixel at zoom level 9

-- Convert from Geohack's scale and dim levels to OSM style zoom levels as used by <maplink>

-- On the equator, it's 305.748 meters/pixel according to https://wiki.openstreetmap.org/wiki/Zoom_levels

-- This quantity depends on the latitude (which we don't have easy access to)

-- Instead, we'll be correct at 38 degrees N, given en-WP bias towards NA and Europe

-- 38N was chosen because:

-- * It's the furthest north where scale=100000 maps to zoom=12

-- * One hemisphere (20000km) maps to zoom=1

local metersPerPixelLevel9 = 305.748*math.cos(math.rad(38))

-- Convert from Geohack's scale to OSM style zoom levels as used by <maplink>

local function geohackScaleToMapZoom(scale)

scale = tonumber(scale)

if not scale or scale <= 0 then return end

return math.log(metersPerPixelLevel9*ppm/scale)/log2 + 9

-- Approximation of https://wiki.openstreetmap.org/wiki/Zoom_levels

end

-- pixel/m from OSM is exact, so use zoom level 9 and 0.3 mm/pixel

return math.log(305.748*ppm/scale)/log2 + 9

-- compute the viewport size (on screen) in meters, assuming ppm pixels per meter on screen

local function computeViewport(args)

local viewport_cm = tonumber(args.viewport_cm)

local viewport_px = tonumber(args.viewport_px)

return viewport_cm and viewport_cm / 100 or viewport_px and viewport_px / ppm

or tonumber(args.default_viewport) or 0.1

end

-- convert from geohack dim (knowing the viewpoint size on screen) to geohack scale

local function geohackDimToScale(dim, units)

local function geohackDimToScale(dim, args)

dim = tonumber(dim)

args = args or {}

if not dim or dim <= 0 then return end

local units = args.units

if units and string.lower(units) == 'km' then

dim = dim*1000

end

return dim / computeViewport(args)

-- geohack assumes a map width of 10cm on the screen

-- which seems nuts, but we have to be compatible

-- thus, dim has to correspond to 10cm, so scale is dim (in meters) * 10

return 10 * dim

end

-- inverse of above function, returning dim in km

local function geohackScaleToDim(scale, args)

scale = tonumber(scale)

args = args or {}

if not scale or scale <= 0 then return end

return scale * computeViewport(args) * 1e-43

end

local oddShape = 2.09 --- length/sqrt(area) of Boston (to choose an example)

-- Convert from Geohack's types to Geohack's scale levels

local function geohackTypeToScale(type, population)

-- Convert from Geohack's types to Geohack dim

local typeScale = {

local function geohackTypeToDim(args)

country = 10000000,

local t = args.type

satellite = 10000000,

if not t then return end

state = 3000000,

local typeDim = mw.loadData('Module:Infobox_dim/data')

adm1st = 1000000,

local dim = typeDim[t]

adm2nd = 300000,

local population = tonumber(args.population)

adm3rd = 100000,

if t == 'city' and population and population > 0 then

city = 100000,

isle = 100000,

mountain = 100000,

river = 100000,

waterbody = 100000,

edu = 10000,

event = 50000,

forest = 50000,

glacier = 50000,

airport = 30000,

landmark = 10000,

railwaystation = 10000,

edu = 10000,

pass = 10000,

camera = 10000

}

local scale

if typeScale[type] then

scale = typeScale[type]

end

population = tonumber(population)

if type == 'city' and population and population > 0 then

-- assume city is a circle with density of 1000/square kilometer

-- compute diameter, in meters. Then multiply by oddShape to account for weird shapes

local diamdim = 35.6868e-3*math.sqrt(population)*oddShape

-- convert to scale

scale = geohackDimToScale(diam)

-- don't zoom in too far

if scaledim < 250005 then

scaledim = 250005

end

end

return scaledim

end

-- Convert from dimension of object to Geohack dim level

local function computeDim(length,width,area)

if length and width then

return 0.5*math.max(length,width)

end

if length then return 0.5*length end

if width then return 0.5*width end

if area then return 0.977oddShape*math.sqrt(area) end

end

-- compute geohack dim from unit arguments (e.g., length_mi)

local function convertDim(args)

for _, arg in pairs({'length_mi','length_km','width_mi','width_km',

'area_mi2','area_km2','area_acre','area_ha'}) do

args[arg] = args[arg] and mw.ustring.gsub(args[arg],",","")

args[arg] = tonumber(args[arg])

if args[arg] and args[arg] <= 0 then args[arg] = nil end

end

local length = args.length_mi and 1.60934*args.length_mi or args.length_km

local width = args.width_mi and 1.60934*args.width_mi or args.width_km

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end

local function computeScale(args)

-- Module entry points

function p._dim(args)

if args.dim then return args.dim end

local dim = convertDim(args)

if not dim then

local scale = args.scale or geohackTypeToScale(args.type, args.population)

dim = geohackScaleToDim(scale)

end

return dim and tostring(math.floor(dim+0.5))..'km'

end

function p._scale(args)

if args.scale then return args.scale end

local dim, units, scale

if args.dim then

dim, units = mw.ustring.match(args.dim,"^([-%d%.]+)%s*(%D*)")

scaleargs.units = geohackDimToScale(dim, units)

args.default_viewport = 0.1 -- default geohack viewpoirt

scale = geohackDimToScale(dim, args)

end

if not scale then

dim = convertDim(args) or geohackTypeToDim(args)

args.units = 'km'

scale = dim and geohackDimToScale(dim, 'km')

args.default_viewport = 0.2 --- when object dimensions or type is specified, assume 20cm viewport

scale = dim and geohackDimToScale(dim, args)

end

if args.type and not scale then return end

scale = math.floor(scale+0.5)

scale = geohackTypeToScale(args.type, args.population)

-- keep scale within sane bounds (OSM zoom levels 1-17)

if scale < 1600 then

scale = 1600

end

returnif scale and> math.floor(scale+0.5)200e6 then

scale = 200e6

end

return scale

end

-- Argument checking

local positiveNumericArgs = {viewport_cm=true,viewport_px=true,length_mi=true,length_km=true,

width_mi=true,width_km=true,area_mi2=true,area_km2=true,

area_acre=true,area_ha=true,scale=true,population=true}

local function cleanArgs(args)

local clean = {}

if type(args) == 'table' then

for k, v in pairs(args) do

if positiveNumericArgs[k] then

v = v and mw.ustring.gsub(v,",","") -- clean out any commas

v = tonumber(v) -- ensure argument is numeric

if v and v <= 0 then -- if non-positive, ignore value

v = nil

end

end

clean[k] = v

end

end

return clean

end

-- Module entry points

function p._dim(args)

args = cleanArgs(args)

if args.dim then return args.dim end

-- compute scale for geohack

local scale = args.scale

local dim

if not scale then

args.default_viewport = 0.2 -- when specifying a object dimension or type, assume output spans 20cm

dim = convertDim(args) or geohackTypeToDim(args)

args.units = 'km'

scale = dim and geohackDimToScale(dim, args)

end

-- reset back to 10cm viewport for correct geohack dim output

args.viewport_cm = 10

dim = scale and geohackScaleToDim(scale, args)

return dim and tostring(math.floor(dim+0.5))..'km'

end

function p._scale(args)

args = cleanArgs(args)

return computeScale(args)

end

function p._zoom(args)

local scale args = p._scalecleanArgs(args)

args.viewport_px = args.viewport_px or 200 --- viewport for Kartographer is 200px high

local scale = computeScale(args)

if scale then

local zoom = geohackScaleToMapZoom(scale)

return zoom and math.floor(zoom+0.5)

end

end