code: @Override
    public void addToMap(Map<String, String> properties, Map<String, List<Float>> rawHistogramData) {
  
      // System.out.println(Arrays.toString(properties.entrySet().toArray()));0
      for (Entry<String, String> entrySet : properties.entrySet()) {
  
        String key = entrySet.getKey();
        String value = entrySet.getValue();
  
        try {
  
          Float floatValue = Float.parseFloat(value);
          if (floatValue > -900.0f) {
            List<Float> rawDataForSingleProperty = rawHistogramData.get(key);
            if (rawDataForSingleProperty == null) {
              rawDataForSingleProperty = new ArrayList<Float>();
            }
            rawDataForSingleProperty.add(floatValue);
            rawHistogramData.put(key, rawDataForSingleProperty);
          }
        } catch (NumberFormatException e) {
          // wasn't a float, skip.
        }
      }
    }
docs: Overriding this to weed out the -999.0 values in the dataset