地圖項目和 FeatureCollection 圖表

ui.Chart.feature 模組包含一組函式，可用來從 Feature 和 FeatureCollection 物件算繪圖表。函式選擇會決定圖表中資料的排列方式，也就是定義 x 軸和 y 軸值，以及定義資料列的方式。請參考下列函式說明和範例，找出最適合您用途的函式和圖表類型。

圖表函式

請參考下列圖表，瞭解各函式如何在圖表中安排地圖項目及其屬性，也就是哪些元素定義 x 值、y 值和系列。

ui.Chart.feature.byFeature

特徵會根據所選屬性的值，沿著 X 軸繪製。系列是由屬性名稱清單定義，其值會沿著 y 軸繪製。

ui.Chart.feature.byProperty

特徵屬性會依名稱沿著 X 軸繪製；指定屬性的值則會沿著 Y 軸繪製。系列是指以所選屬性值標示的地圖項目。

ui.Chart.feature.groups

特徵會根據所選屬性的值，沿著 X 軸繪製。系列是由特定屬性的不重複值定義。而 Y 軸位置則是由指定屬性的值定義。

ui.Chart.feature.histogram

所選屬性值的頻率直方圖。

• X 軸：所選屬性值的直方圖值區
• Y 軸：每個直方圖值區符合條件的功能頻率

資料範例

以下範例會使用 FeatureCollection，該 FeatureCollection 由三個生態區域地圖項目組成，其中屬性描述氣候標準。

查看示例資料的建立方式

程式碼編輯器 (JavaScript)

// Define three representative ecoregions in the USA.
var desert = ee.Feature(
    ee.Geometry.Rectangle(-109.21, 31.42, -108.3, 32.03),
    {label: 'Desert', value: 0});

var forest = ee.Feature(
    ee.Geometry.Rectangle(-122.73, 43.45, -122.28, 43.91),
    {label: 'Forest', value: 1});

var grassland = ee.Feature(
    ee.Geometry.Rectangle(-101.81, 41.7, -100.53, 42.51),
    {label: 'Grassland', value: 2});

// Combine features into a feature collection.
var ecoregions = ee.FeatureCollection([desert, forest, grassland]);

// Load PRISM climate normals image collection; convert images to bands.
var normClim = ee.ImageCollection('OREGONSTATE/PRISM/Norm81m').toBands();

// Summarize climate normals for each ecoregion feature as a set or properties.
ecoregions = normClim.reduceRegions(
    {collection: ecoregions, reducer: ee.Reducer.mean(), scale: 5e4});

// Add a property for whether January temperature is warm or not.
ecoregions = ecoregions.map(function(ecoregion) {
  return ecoregion.set('warm', ee.Number(ecoregion.get('01_tmean')).gt(0));
});

ui.Chart.feature.byFeature

柱狀圖

地圖上會沿著 X 軸繪製地圖項目，並以所選屬性的值標示。系列由相鄰的資料欄表示，這些資料欄是由屬性名稱清單定義，其值會沿著 y 軸繪製。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions.select('[0-9][0-9]_tmean|label'),
          xProperty: 'label',
        })
        .setSeriesNames([
          'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
          'Nov', 'Dec'
        ])
        .setChartType('ColumnChart')
        .setOptions({
          title: 'Average Monthly Temperature by Ecoregion',
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxis: {
            title: 'Temperature (°C)',
            titleTextStyle: {italic: false, bold: true}
          },
          colors: [
            '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
            'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
          ]
        });
print(chart);

長條圖

地圖上沿著 y 軸繪製的功能，會以所選屬性的值標示。序列由相鄰的長條表示，這些長條是由屬性名稱清單定義，其值會沿著 x 軸繪製。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions.select('[0-9][0-9]_tmean|label'),
          xProperty: 'label',
        })
        .setSeriesNames([
          'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
          'Nov', 'Dec'
        ])
        .setChartType('BarChart')
        .setOptions({
          title: 'Average Monthly Temperature by Ecoregion',
          hAxis: {
            title: 'Temperature (°C)',
            titleTextStyle: {italic: false, bold: true}
          },
          vAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          colors: [
            '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
            'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
          ]
        });
print(chart);

堆疊柱狀圖

絕對值

地圖上會沿著 X 軸繪製地圖項目，並以所選屬性的值標示。序列由堆疊的資料欄表示，這些資料欄是由屬性名稱清單定義，其值會沿著 y 軸繪製為累積序列和。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions.select('[0-9][0-9]_ppt|label'),
          xProperty: 'label'
        })
        .setSeriesNames([
          'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
          'Nov', 'Dec'
        ])
        .setChartType('ColumnChart')
        .setOptions({
          title: 'Average Monthly Precipitation by Ecoregion',
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxis: {
            title: 'Precipitation (mm)',
            titleTextStyle: {italic: false, bold: true}
          },
          colors: [
            '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
            'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
          ],
          isStacked: 'absolute'
        });
print(chart);

相對時間

地圖上會沿著 X 軸繪製地圖項目，並以所選屬性的值標示。系列由堆疊的資料欄表示，這些資料欄是由屬性名稱清單定義，其值會沿著 y 軸繪製，並以總和系列的百分比表示。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions.select('[0-9][0-9]_ppt|label'),
          xProperty: 'label'
        })
        .setSeriesNames([
          'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
          'Nov', 'Dec'
        ])
        .setChartType('ColumnChart')
        .setOptions({
          title: 'Average Monthly Precipitation by Ecoregion',
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxis: {
            title: 'Precipitation (mm)',
            titleTextStyle: {italic: false, bold: true}
          },
          colors: [
            '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
            'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
          ],
          isStacked: 'percent'
        });
print(chart);

散佈圖

地圖上會沿著 X 軸繪製地圖項目，並以所選屬性的值標示。系列會以點表示，這些點是由屬性名稱清單定義，其值會沿著 y 軸繪製。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions,
          xProperty: 'label',
          yProperties: ['01_tmean', '07_tmean']
        })
        .setSeriesNames(['Jan', 'Jul'])
        .setChartType('ScatterChart')
        .setOptions({
          title: 'Average Monthly Temperature by Ecoregion',
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxis: {
            title: 'Temperature (°C)',
            titleTextStyle: {italic: false, bold: true}
          },
          pointSize: 10,
          colors: ['1d6b99', 'cf513e'],
        });
print(chart);

組合圖

地圖上會沿著 X 軸繪製地圖項目，並以所選屬性的值標示。系列會以點和資料欄表示，這些項目是由屬性名稱清單定義，其值會沿著 y 軸繪製。這張圖表是使用兩個軸和系列專屬樣式繪製而成。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .byFeature({
          features: ecoregions,
          xProperty: 'label',
          yProperties: ['06_ppt', '06_tmean']
        })
        .setSeriesNames(['Precipitation', 'Temperature'])
        .setChartType('ColumnChart')
        .setOptions({
          title: 'Average June Temperature and Precipitation by Ecoregion',
          series: {
            0: {targetAxisIndex: 1, type: 'bar', color: '1d6b99'},
            1: {
              targetAxisIndex: 0,
              type: 'line',
              lineWidth: 0,
              pointSize: 10,
              color: 'e37d05'
            }
          },
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxes: {
            0: {
              title: 'Temperature (°C)',
              baseline: 0,
              titleTextStyle: {italic: false, bold: true, color: 'e37d05'}
            },
            1: {
              title: 'Precipitation (mm)',
              titleTextStyle: {italic: false, bold: true, color: '1d6b99'}
            },
          },
          bar: {groupWidth: '40%'},
        });
print(chart);

ui.Chart.feature.byProperty

設定範例

ui.Chart.feature.byProperty 函式會接受字典，讓您藉由為屬性名稱指派數值來控制屬性名稱的標籤和順序。下列笛卡爾座標圖表使用此選項，針對每月平均降雨量設定月份標籤，並依時間順序排序月份名稱。

柱狀圖

特徵屬性會沿著 x 軸繪製，並根據字典輸入內容標示及排序；指定屬性的值則會沿著 y 軸繪製。系列是功能，以資料欄表示，並以所選屬性的值標示。如要轉換為長條圖，請使用 .setChartType('BarChart')。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define a dictionary that associates property names with values and labels.
var precipInfo = {
  '01_ppt': {v: 1, f: 'Jan'},
  '02_ppt': {v: 2, f: 'Feb'},
  '03_ppt': {v: 3, f: 'Mar'},
  '04_ppt': {v: 4, f: 'Apr'},
  '05_ppt': {v: 5, f: 'May'},
  '06_ppt': {v: 6, f: 'Jun'},
  '07_ppt': {v: 7, f: 'Jul'},
  '08_ppt': {v: 8, f: 'Aug'},
  '09_ppt': {v: 9, f: 'Sep'},
  '10_ppt': {v: 10, f: 'Oct'},
  '11_ppt': {v: 11, f: 'Nov'},
  '12_ppt': {v: 12, f: 'Dec'}
};

// Organize property information into objects for defining x properties and
// their tick labels.
var xPropValDict = {};  // Dictionary to codify x-axis property names as values.
var xPropLabels = [];   // Holds dictionaries that label codified x-axis values.
for (var key in precipInfo) {
  xPropValDict[key] = precipInfo[key].v;
  xPropLabels.push(precipInfo[key]);
}

// Define the chart and print it to the console.
var chart = ui.Chart.feature
                .byProperty({
                  features: ecoregions,
                  xProperties: xPropValDict,
                  seriesProperty: 'label'
                })
                .setChartType('ColumnChart')
                .setOptions({
                  title: 'Average Ecoregion Precipitation by Month',
                  hAxis: {
                    title: 'Month',
                    titleTextStyle: {italic: false, bold: true},
                    ticks: xPropLabels
                  },
                  vAxis: {
                    title: 'Precipitation (mm)',
                    titleTextStyle: {italic: false, bold: true}
                  },
                  colors: ['f0af07', '0f8755', '76b349'],
                });
print(chart);

折線圖

特徵屬性會沿著 x 軸繪製，並根據字典輸入內容標示及排序；指定屬性的值則會沿著 y 軸繪製。系列是指以線條表示的特徵，並以所選屬性的值標示。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define a dictionary that associates property names with values and labels.
var precipInfo = {
  '01_ppt': {v: 1, f: 'Jan'},
  '02_ppt': {v: 2, f: 'Feb'},
  '03_ppt': {v: 3, f: 'Mar'},
  '04_ppt': {v: 4, f: 'Apr'},
  '05_ppt': {v: 5, f: 'May'},
  '06_ppt': {v: 6, f: 'Jun'},
  '07_ppt': {v: 7, f: 'Jul'},
  '08_ppt': {v: 8, f: 'Aug'},
  '09_ppt': {v: 9, f: 'Sep'},
  '10_ppt': {v: 10, f: 'Oct'},
  '11_ppt': {v: 11, f: 'Nov'},
  '12_ppt': {v: 12, f: 'Dec'}
};

// Organize property information into objects for defining x properties and
// their tick labels.
var xPropValDict = {};  // Dictionary to codify x-axis property names as values.
var xPropLabels = [];   // Holds dictionaries that label codified x-axis values.
for (var key in precipInfo) {
  xPropValDict[key] = precipInfo[key].v;
  xPropLabels.push(precipInfo[key]);
}

// Define the chart and print it to the console.
var chart = ui.Chart.feature
                .byProperty({
                  features: ecoregions,
                  xProperties: xPropValDict,
                  seriesProperty: 'label'
                })
                .setChartType('ScatterChart')
                .setOptions({
                  title: 'Average Ecoregion Precipitation by Month',
                  hAxis: {
                    title: 'Month',
                    titleTextStyle: {italic: false, bold: true},
                    ticks: xPropLabels
                  },
                  vAxis: {
                    title: 'Precipitation (mm)',
                    titleTextStyle: {italic: false, bold: true}
                  },
                  colors: ['f0af07', '0f8755', '76b349'],
                  lineSize: 5,
                  pointSize: 0
                });
print(chart);

面積圖

特徵屬性會沿著 x 軸繪製，並根據字典輸入內容標示及排序；指定屬性的值則會沿著 y 軸繪製。系列是指以線條和陰影區域表示的地圖項目，並以所選屬性的值標示。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define a dictionary that associates property names with values and labels.
var precipInfo = {
  '01_ppt': {v: 1, f: 'Jan'},
  '02_ppt': {v: 2, f: 'Feb'},
  '03_ppt': {v: 3, f: 'Mar'},
  '04_ppt': {v: 4, f: 'Apr'},
  '05_ppt': {v: 5, f: 'May'},
  '06_ppt': {v: 6, f: 'Jun'},
  '07_ppt': {v: 7, f: 'Jul'},
  '08_ppt': {v: 8, f: 'Aug'},
  '09_ppt': {v: 9, f: 'Sep'},
  '10_ppt': {v: 10, f: 'Oct'},
  '11_ppt': {v: 11, f: 'Nov'},
  '12_ppt': {v: 12, f: 'Dec'}
};

// Organize property information into objects for defining x properties and
// their tick labels.
var xPropValDict = {};  // Dictionary to codify x-axis property names as values.
var xPropLabels = [];   // Holds dictionaries that label codified x-axis values.
for (var key in precipInfo) {
  xPropValDict[key] = precipInfo[key].v;
  xPropLabels.push(precipInfo[key]);
}

// Define the chart and print it to the console.
var chart = ui.Chart.feature
                .byProperty({
                  features: ecoregions,
                  xProperties: xPropValDict,
                  seriesProperty: 'label'
                })
                .setChartType('AreaChart')
                .setOptions({
                  title: 'Average Ecoregion Precipitation by Month',
                  hAxis: {
                    title: 'Month',
                    titleTextStyle: {italic: false, bold: true},
                    ticks: xPropLabels
                  },
                  vAxis: {
                    title: 'Precipitation (mm)',
                    titleTextStyle: {italic: false, bold: true}
                  },
                  colors: ['f0af07', '0f8755', '76b349'],
                  lineSize: 5,
                  pointSize: 0,
                  curveType: 'function'
                });
print(chart);

圓餅圖

圓餅圖是一種特徵，每個切片都是屬性標籤，其值會以百分比表示，該百分比是組成圓餅的所有屬性值總和的百分比。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Subset the forest ecoregion feature and select the monthly precipitation
// properties, rename them as abbreviated months.
var thisForest = ecoregions.filter(ee.Filter.eq('label', 'Forest'))
                     .select(Object.keys(precipInfo), [
                       'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
                       'Sep', 'Oct', 'Nov', 'Dec'
                     ]);

// Define the chart and print it to the console.
var chart = ui.Chart.feature
                .byProperty({
                  features: thisForest,
                  xProperties: [
                    'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
                    'Sep', 'Oct', 'Nov', 'Dec'
                  ]
                })
                .setChartType('PieChart')
                .setOptions({
                  title: 'Average Monthly Precipitation for Forest Ecoregion',
                  colors: [
                    '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
                    'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
                  ]
                });
print(chart);

圓環圖

設定 pieHole 圖表選項，即可將圓餅圖轉換為圓環圖；在大多數圖表中，0.4 到 0.6 之間的數字會顯示最佳效果。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Subset the forest ecoregion feature and select the monthly precipitation
// properties, rename them as abbreviated months.
var thisForest = ecoregions.filter(ee.Filter.eq('label', 'Forest'))
                     .select(Object.keys(precipInfo), [
                       'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
                       'Sep', 'Oct', 'Nov', 'Dec'
                     ]);

// Define the chart and print it to the console.
var chart = ui.Chart.feature
                .byProperty({
                  features: thisForest,
                  xProperties: [
                    'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
                    'Sep', 'Oct', 'Nov', 'Dec'
                  ]
                })
                .setChartType('PieChart')
                .setOptions({
                  title: 'Average Monthly Precipitation for Forest Ecoregion',
                  colors: [
                    '604791', '1d6b99', '39a8a7', '0f8755', '76b349', 'f0af07',
                    'e37d05', 'cf513e', '96356f', '724173', '9c4f97', '696969'
                  ],
                  pieHole: 0.4,
                });
print(chart);

ui.Chart.feature.groups

柱狀圖

地圖項目會沿著 X 軸繪製，並以所選屬性的值標示。系列會以資料欄表示，這些資料欄是由特定屬性的一組不重複值定義。以特定屬性的值定義 Y 軸位置。您可以將圖表類型設為 'ScatterChart' (.setChartType('ScatterChart'))，將此散布圖變更為散布圖。如果時間是 x 軸變數，您可能會想使用折線圖：.setChartType('LineChart')。

程式碼編輯器 (JavaScript)

// Import the example feature collection.
var ecoregions = ee.FeatureCollection('projects/google/charts_feature_example');

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .groups({
          features: ecoregions,
          xProperty: 'label',
          yProperty: '01_tmean',
          seriesProperty: 'warm'
        })
        .setSeriesNames(['Warm', 'Cold'])
        .setChartType('ColumnChart')
        .setOptions({
          title: 'Average January Temperature by Ecoregion',
          hAxis:
              {title: 'Ecoregion', titleTextStyle: {italic: false, bold: true}},
          vAxis: {
            title: 'Jan temp (°C)',
            titleTextStyle: {italic: false, bold: true}
          },
          bar: {groupWidth: '80%'},
          colors: ['cf513e', '1d6b99'],
          isStacked: true
        });
print(chart);

ui.Chart.feature.histogram

x 軸是根據所選屬性值範圍的值區間定義；y 軸則是指定區間內的元素數量。

程式碼編輯器 (JavaScript)

// Load PRISM climate normals image collection; convert images to bands.
var normClim = ee.ImageCollection('OREGONSTATE/PRISM/Norm81m').toBands();

// Make a point sample of climate variables for a region in western USA.
var region = ee.Geometry.Rectangle(-123.41, 40.43, -116.38, 45.14);
var climSamp = normClim.sample(region, 5000);

// Define the chart and print it to the console.
var chart =
    ui.Chart.feature
        .histogram({features: climSamp, property: '07_ppt', maxBuckets: 30})
        .setOptions({
          title: 'July Precipitation Distribution for NW USA',
          hAxis: {
            title: 'Precipitation (mm)',
            titleTextStyle: {italic: false, bold: true}
          },
          vAxis: {
            title: 'Pixel count',
            titleTextStyle: {italic: false, bold: true}
          },
          colors: ['1d6b99'],
          legend: {position: 'none'}
        });
print(chart);