[Enhancement] Choose layer color by default (point layer)

src/layers/geojson-layer/geojson-layer.js

@@ -243,7 +243,7 @@ export default class GeoJsonLayer extends Layer {
     this.updateMeta({bounds, fixedRadius, featureTypes});
   }
 
-  setInitialLayerConfig(allData) {
+  setInitialLayerConfig({allData}) {
     this.updateLayerMeta(allData);
 
     const {featureTypes} = this.meta;

src/layers/h3-hexagon-layer/h3-hexagon-layer.js

@@ -19,6 +19,7 @@
 // THE SOFTWARE.
 
 import Layer from '../base-layer';
+import {findDefaultColorField} from 'utils/dataset-utils';
 import {GeoJsonLayer} from '@deck.gl/layers';
 import {H3HexagonLayer} from '@deck.gl/geo-layers';
 import EnhancedColumnLayer from 'deckgl-layers/column-layer/enhanced-column-layer';
@@ -97,6 +98,19 @@ export default class HexagonIdLayer extends Layer {
     };
   }
 
+  setInitialLayerConfig(dataset) {
+    const defaultColorField = findDefaultColorField(dataset);
+
+    if (defaultColorField) {
+      this.updateLayerConfig({
+        colorField: defaultColorField
+      });
+      this.updateLayerVisualChannel(dataset, 'color');
+    }
+
+    return this;
+  }
+
   static findDefaultLayerProps({fields = [], allData = []}) {
     const hexFields = getHexFields(fields, allData);
     if (!hexFields.length) {

src/layers/point-layer/point-layer.js

@@ -23,6 +23,7 @@ import {ScatterplotLayer} from '@deck.gl/layers';
 
 import Layer from '../base-layer';
 import {hexToRgb} from 'utils/color-utils';
+import {findDefaultColorField} from 'utils/dataset-utils';
 import PointLayerIcon from './point-layer-icon';
 import {DEFAULT_LAYER_COLOR, CHANNEL_SCALES} from 'constants/default-settings';
 
@@ -126,6 +127,19 @@ export default class PointLayer extends Layer {
     };
   }
 
+  setInitialLayerConfig(dataset) {
+    const defaultColorField = findDefaultColorField(dataset);
+
+    if (defaultColorField) {
+      this.updateLayerConfig({
+        colorField: defaultColorField
+      });
+      this.updateLayerVisualChannel(dataset, 'color');
+    }
+
+    return this;
+  }
+
   static findDefaultLayerProps({fieldPairs = []}) {
     const props = [];
 

src/layers/trip-layer/trip-layer.js

@@ -235,7 +235,7 @@ export default class TripLayer extends Layer {
     this.updateMeta({bounds, featureTypes, getFeature});
   }
 
-  setInitialLayerConfig(allData) {
+  setInitialLayerConfig({allData}) {
     this.updateLayerMeta(allData);
     return this;
   }

src/utils/dataset-utils.js

@@ -20,7 +20,7 @@
 
 import {hexToRgb} from './color-utils';
 import uniq from 'lodash.uniq';
-import {TRIP_POINT_FIELDS, SORT_ORDER} from 'constants/default-settings';
+import {ALL_FIELD_TYPES, TRIP_POINT_FIELDS, SORT_ORDER} from 'constants/default-settings';
 import {generateHashId} from './utils';
 import {validateInputData} from 'processors/data-processor';
 import {getGpuFilterProps} from 'utils/gpu-filter-utils';
@@ -213,3 +213,30 @@ export function sortDatasetByColumn(dataset, column, mode) {
     sortOrder
   };
 }
+
+/**
+ * Choose a field to use as the default color field of a layer.
+ *
+ * Right now this implements a very simple heuristic looking
+ * for a real-type field that is not lat/lon.
+ *
+ * In the future we could consider other things:
+ * Consider integer fields
+ * look for highest dynamic range (using a sample of the data)
+ * Look for particular names to select ("value", "color", etc)
+ * Look for particular names to avoid ("" - the Pandas index column)
+ *
+ * @param dataset
+ */
+export function findDefaultColorField({fields, fieldPairs = []}) {
+  const defaultField = fields.find(
+    f =>
+      f.type === ALL_FIELD_TYPES.real &&
+      // Do not permit lat, lon fields
+      !fieldPairs.find(pair => pair.pair.lat.value === f.name || pair.pair.lng.value === f.name)
+  );
+  if (!defaultField) {
+    return null;
+  }
+  return defaultField;
+}

src/utils/layer-utils.js

@@ -48,7 +48,7 @@ export function findDefaultLayer(dataset, layerClasses) {
   return layerProps.map(props => {
     const layer = new layerClasses[props.type](props);
     return typeof layer.setInitialLayerConfig === 'function' && Array.isArray(dataset.allData)
-      ? layer.setInitialLayerConfig(dataset.allData)
+      ? layer.setInitialLayerConfig(dataset)
       : layer;
   });
 }

test/node/utils/dataset-utils-test.js

@@ -0,0 +1,51 @@
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+import test from 'tape';
+import {findDefaultColorField} from 'utils/dataset-utils';
+import {createNewDataEntry} from 'utils/dataset-utils';
+import {processCsvData} from 'processors/data-processor';
+
+import csvData from 'test/fixtures/test-layer-data';
+
+test('datasetUtils.findDefaultColorField', t => {
+  const dataset = createNewDataEntry({
+    info: {id: 'taro'},
+    data: processCsvData(csvData)
+  })['taro'];
+
+  const defaultField = findDefaultColorField(dataset);
+  // Unfortunately lat_1 is not detected as part of a field pair :(
+  t.equals(defaultField.name, 'lat_1', 'default field name is OK');
+
+  t.end();
+});
+
+test('datasetUtils.findDefaultColorField empty', t => {
+  const dataset = createNewDataEntry({
+    info: {id: 'taro'},
+    data: processCsvData('a\na')
+  })['taro'];
+
+  const defaultField = findDefaultColorField(dataset);
+  t.notOk(defaultField, 'default field is null');
+
+  t.end();
+});

test/node/utils/index.js

@@ -22,6 +22,7 @@ import './data-utils-test';
 import './data-processor-test';
 import './filter-utils-test';
 import './gpu-filter-utils-test';
+import './dataset-utils-test';
 import './layer-utils-test';
 import './data-scale-utils-test';
 import './interaction-utils-test';