subtract US-SEC from US-FL

...using polygon-clipping.difference(). next commit will undo this and just build US-FL from the non-SEC Florida counties instead.

for electricitymaps#1713

web/generate-geometries.js

@@ -744,6 +744,18 @@ const sec = topojson.topology({'US-SEC': zones['US-SEC']})
 const secMerged = topojson.mergeArcs(sec, [sec.objects['US-SEC']]);
 zones['US-SEC'] = topojson.feature(sec, secMerged)
 
+// Subtract US-SEC from Florida (US-FL)
+const clipping = require('polygon-clipping');
+zones['US-FL'] = {
+  "type": "Feature",
+  "properties": {},
+  "geometry": {
+    "type": "MultiPolygon",
+    "coordinates": clipping.difference(zones['US-FL'].geometry.coordinates,
+                                       zones['US-SEC'].geometry.coordinates)
+  }
+}
+
 // create zonesMoreDetails by getting zone having moreDetails===true
 let zonesMoreDetails = {};
 zoneDefinitions.forEach(zone => {

web/yarn.lock

@@ -5017,6 +5017,13 @@ pluralize@^7.0.0:
   version "7.0.0"
   resolved "https://registry.yarnpkg.com/pluralize/-/pluralize-7.0.0.tgz#298b89df8b93b0221dbf421ad2b1b1ea23fc6777"
 
+polygon-clipping@^0.14.2:
+  version "0.14.2"
+  resolved "https://registry.yarnpkg.com/polygon-clipping/-/polygon-clipping-0.14.2.tgz#5c1b2f61fcf465172750fcdeaed977b0dd7f83f3"
+  integrity sha512-X0gxP42HkzxxF+MRA3BPoY9A0N9Y2rho9SGJQrLaKGAco6yLTDj/mHRwo45raD8exLvzDXjNKHKZ6bD7MC8hSA==
+  dependencies:
+    splaytree "^3.0.0"
+
 posix-character-classes@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/posix-character-classes/-/posix-character-classes-0.1.1.tgz#01eac0fe3b5af71a2a6c02feabb8c1fef7e00eab"
@@ -6135,6 +6142,11 @@ spdx-license-ids@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/spdx-license-ids/-/spdx-license-ids-3.0.0.tgz#7a7cd28470cc6d3a1cfe6d66886f6bc430d3ac87"
 
+splaytree@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/splaytree/-/splaytree-3.0.0.tgz#959301153652d2d6fac15a38843e8149ece326a1"
+  integrity sha512-/FXCGITlLdmudFnMGSql9FO4P8Xfq3FgxUqiFlJtoQ7/nXqTqKn79xfhGuN+Yt/1kEFmcRUvv9yVjHAOOmqKWA==
+
 split-string@^3.0.1, split-string@^3.0.2:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/split-string/-/split-string-3.1.0.tgz#7cb09dda3a86585705c64b39a6466038682e8fe2"