Merge pull request #53 from carbonplan/katamartin/equally-spaced-vali…

…dation

Add validation check that proxied datasets have equally spaced spatial coordinates

components/utils/data.js

@@ -8,7 +8,7 @@ import {
   // LZ4,
   // Zstd,
 } from 'numcodecs'
-
+import { deviation } from 'd3-array'
 import { PROJECTIONS, ASPECTS } from '../constants'
 
 const COMPRESSORS = {
@@ -270,6 +270,21 @@ export const getVariableLevelInfo = async (
   const axes = ['X', 'Y'].reduce((accum, key, i) => {
     const index = dimensions.indexOf(cfAxes[name][key])
     const array = coordinates[i]
+    if (!pyramid) {
+      const stepValues = array.data.reduce((a, d, i) => {
+        if (i === 0) return a
+        const delta = d - array.data[i - 1]
+        a.add(delta)
+        return a
+      }, new Set())
+      const stepDeviation = deviation(stepValues)
+      if (stepDeviation && stepDeviation > 1e-3) {
+        throw new Error(
+          `Cannot handle coordinate: ${cfAxes[name][key]}. Spatial coordinates must be equally spaced.`
+        )
+      }
+    }
+
     const step = Math.abs(Number(array.data[0]) - Number(array.data[1]))
     const reversed = array.data[0] > array.data[array.data.length - 1]
 

package.json

@@ -35,6 +35,7 @@
     "@mdx-js/react": "^2.1.5",
     "@next/mdx": "^12.3.1",
     "@theme-ui/color": "^0.15.3",
+    "d3-array": "^3.1.0",
     "d3-format": "^3.1.0",
     "d3-geo": "^3.1.0",
     "d3-scale": "^3.1.0",