feat: Improve styling of SVG map

Author: ptbrowne

website/src/pages/api/v0.ts

@@ -23,10 +23,48 @@ const cors = initMiddleware(
   })
 );
 
+const truthy = <T>(x: T): x is Exclude<T, undefined | null> => {
+  return Boolean(x);
+};
 
 const makeMapshaperStyleCommands = (
+  shapeStyles: Record<
+    string,
+    null | {
+      fill?: string;
+      stroke?: string;
+    }
+  >
+) => {
+  return Object.entries(shapeStyles)
+    .map(([shapeName, style]) => {
+      if (style === null) {
+        return style;
+      }
+      return `-style target='${shapeName}' ${Object.entries(style)
+        .map(([propName, propValue]) => {
+          return `${propName}='${propValue}'`;
+        })
+        .join(" ")}`;
+    })
+    .filter(truthy);
+};
 
+const getShapeZIndex = (shape: string) => {
+  if (shape.includes("country")) {
+    return 3;
+  } else if (shape.includes("cantons")) {
+    return 2;
+  } else if (shape.includes("lakes")) {
+    return 1;
+  }
+  return 0;
+};
 
+const shapeIndexComparator = (a: string, b: string) => {
+  const za = getShapeZIndex(a);
+  const zb = getShapeZIndex(b);
+  return za === zb ? 0 : za < zb ? -1 : 1;
 };
 
 export default async function handler(
@@ -45,17 +83,47 @@ export default async function handler(
     }
 
     const cwd = process.cwd();
+    const shpFilenames = [...options.shapes]
+      .map((shapeName) => {
+        return path.join(cwd, "public", "swiss-maps", year, `${shapeName}.shp`);
+      })
+      .sort(shapeIndexComparator);
+
+    const hasCantons = shapes.has("cantons");
+    const hasMunicipalities = shapes.has("municipalities");
+    const hasLakes = shapes.has("lakes");
+
+    const shapeStyles = {
+      country: {
+        fill: hasCantons || hasMunicipalities ? "transparent" : "#eee",
+        stroke: "#111",
+      },
+      lakes: hasLakes
+        ? {
+            fill: "#a1d0f7",
+          }
+        : null,
+      cantons: hasCantons
+        ? {
+            fill: hasMunicipalities ? "transparent" : "#eee",
+            stroke: "#666",
+          }
+        : null,
+      municipalities: hasMunicipalities
+        ? {
+            fill: "#eee",
+            stroke: hasCantons ? "#bbb" : "#666",
+          }
+        : null,
+    };
+
+    const styleCommands = makeMapshaperStyleCommands(shapeStyles);
+
     const output = await generate({
       ...options,
-      shpFilenames: [...options.shapes].map((shapeName) => {
-        return path.join(cwd, "public", "swiss-maps", year, `${shapeName}.shp`);
-      }),
+      shpFilenames: shpFilenames,
       mapshaperCommands: [
-        // svg coloring, otherwise is all bblack
-        shapes.has("cantons")
-          ? `-style fill='#e6e6e6' stroke='#999' target='cantons'`
-          : "",
-        shapes.has("lakes") ? `-style fill='#a1d0f7' target='lakes'` : "",
+        ...styleCommands,
         `-o output.${format} format=${format} target=*`,
       ],
     });