tip on a geo mark without a projection should not collapse the chart

src/plot.js

@@ -14,7 +14,7 @@ import {arrayify, map, yes, maybeIntervalTransform, subarray} from "./options.js
 import {createProjection, getGeometryChannels, hasProjection} from "./projection.js";
 import {createScales, createScaleFunctions, autoScaleRange, exposeScales} from "./scales.js";
 import {innerDimensions, outerDimensions} from "./scales.js";
-import {position, registry as scaleRegistry} from "./scales/index.js";
+import {isPosition, registry as scaleRegistry} from "./scales/index.js";
 import {applyInlineStyles, maybeClassName} from "./style.js";
 import {initializer} from "./transforms/basic.js";
 import {consumeWarnings, warn} from "./warnings.js";
@@ -201,7 +201,7 @@ export function plot(options = {}) {
           // channels as-is rather than creating new scales, and assume that
           // they already have the scale’s transform applied, if any (e.g., when
           // generating ticks for the axis mark).
-          if (scale != null && scaleRegistry.get(scale) !== position) {
+          if (scale != null && !isPosition(scaleRegistry.get(scale))) {
             applyScaleTransform(channel, options);
             newByScale.add(scale);
           }

src/scales/index.js

@@ -23,6 +23,7 @@ export const opacity = Symbol("opacity");
 export const symbol = Symbol("symbol");
 
 // There isn’t really a projection scale; this represents x and y for geometry.
+// This is used to denote channels that should be projected.
 export const projection = Symbol("projection");
 
 // TODO Rather than hard-coding the list of known scale names, collect the names
@@ -40,3 +41,7 @@ export const registry = new Map([
   ["length", length],
   ["projection", projection]
 ]);
+
+export function isPosition(kind) {
+  return kind === position || kind === projection;
+}

src/transforms/centroid.js

@@ -11,7 +11,14 @@ export function centroid({geometry = identity, ...options} = {}) {
     const Y = new Float64Array(n);
     const path = geoPath(projection);
     for (let i = 0; i < n; ++i) [X[i], Y[i]] = path.centroid(G[i]);
-    return {data, facets, channels: {x: {value: X, source: null}, y: {value: Y, source: null}}};
+    return {
+      data,
+      facets,
+      channels: {
+        x: {value: X, scale: projection == null ? "x" : null, source: null},
+        y: {value: Y, scale: projection == null ? "y" : null, source: null}
+      }
+    };
   });
 }