Skip to content

Use Mercator area to filter features #934

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
M393 wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Use Mercator area to filter features #934

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 14 additions & 2 deletions resources/process-openmaptiles.lua
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -742,7 +742,7 @@ function way_function()
Layer("landuse", true)
Attribute("class", l)
if l=="residential" then
if Area()<ZRES8^2 then MinZoom(8)
if MercatorArea()<ZRES8^2 then MinZoom(8)
else SetMinZoomByArea() end
else MinZoom(11) end
write_name = true
Expand Down Expand Up @@ -870,14 +870,26 @@ function SetBrunnelAttributes()
end
end

-- Area of the feature in Web Mercator square metres.
function MercatorArea()
local area = Area()
if area == 0 then return 0 end
local centre = Centroid("centroid")
if centre == nil then return area end
-- Clamp to the Web Mercator cutoff: beyond it nothing is rendered anyway
local lat = math.min(math.abs(centre[1]), 85.05112878)
local coslat = math.cos(math.rad(lat))
return area / (coslat * coslat)
end

-- Set minimum zoom level by area
function SetMinZoomByArea()
SetMinZoomByAreaWithLimit(0)
end

-- Set minimum zoom level by area but not below given minzoom
function SetMinZoomByAreaWithLimit(minzoom)
local area=Area()
local area=MercatorArea()
if minzoom <= 1 and area>ZRES0^2 then MinZoom(1)
elseif minzoom <= 2 and area>ZRES1^2 then MinZoom(2)
elseif minzoom <= 3 and area>ZRES2^2 then MinZoom(3)
Expand Down