All text that comes through Caravel automatically has its sentiment classified. In the user interface, sentiment is displayed as part of a Classifier's labels. It can be one of five values: Very Negative, Negative, Neutral, Positive, or Very Positive..
In feed reports and insight data passed to automations, you have access to both the Sentiment value and the Sentiment Score which is a value between -100 to 100. -100 being the most negative and 100 the most positive.
Aspect-based sentiment analysis is when the attributes or components that are being mentioned are analyzed for sentiment as opposed to the overall sentiment of a document or message. In Caravel, aspect-based sentiment is done in combination with your classifiers.
By default, when you create a classifier, the sentiment of that classification is also automatically determined. You can control wether or not you want to classify sentiment with your classifier in the Setup step while creating custom classifiers.