Overview

AMCharts is a Javascript chart library that provides a variety of different charts and graphs that are pleasing to the eye and easy to use. We seek to make using their products more convenient for developers who are accessing data made available through RDS.

Formatting Tabulations

• In this example we will create a dataProvider object that can be used with amCharts. We will assume that we have a collection named test and a view named view with a variable named var that has the values 1, 2, and 3. In this example we will run a tabulation that will count the frequencies of each of these values that could be used to create a chart.

• Running the tabulation would normally look something like this:

  Tabulation

  http://{host}/rds/api/catalog/test/view/tabulate?dims=var

  
  

  Tabulation Output Expand source

   {
      "records": [
          [
              1,
              182
          ],
          [
              2,
              354
          ],
          [
              3,
              126
          ]
      ],
      "info": {
          "colCount": 2,
          "format": "MTNA",
          "includeMetadata": false,
          "limit": 20,
          "offset": 0,
          "moreRows": false
      }
  }

  
  

• We can add the format parameter to specify we want this to be output in a way that amCharts expects to see it. 

  Tabulation amCharts

  http://{host}/rds/api/catalog/test/view/tabulate?dims=var&format=amcharts

  
  

  Tabulation amCharts Output Expand source

  {
      "dataProvider": [
          {
              "var": 1,
              "count": 182
          },
          {
              "var": 2,
              "count": 354
          },
          {
              "var": 3,
              "count": 126
          }
      ]
  } 

  
  

• In addition to formatting the values in a dataProvider, we can also substitute the numeric values for the categories they represent if the variable has a classification associated with it. In this example we will assume that var has the following classification:

  1	METROPOLITAN AREA
  2	TOWN OR CITY
  3	OPEN COUNTRY

  With this in mind, all we have to do is specify the metadata parameter and the output will have the categories instead of the numeric values.

  Tabulation amCharts With Metadata

  http://{host}/rds/api/catalog/test/view/tabulate?dims=var&format=amcharts&metadata 

  
  

  Tabulation amCharts Output With Categories Expand source

   {
      "dataProvider": [
          {
              "var": "METROPOLITAN AREA",
              "count": 182
          },
          {
              "var": "TOWN OR CITY",
              "count": 354
          },
          {
              "var": "OPEN COUNTRY",
              "count": 126
          }
      ]
  }