An API is an interface that allows software programs to interact with each other, while an SDK is a set of tools that can be used to develop software applications targeting a specific platform. The simplest version of an SDK might be an API that contains some of the files needed to interact with a particular programming language. So an API can be seen as a simple SDK without debugging support, etc.
The SDK allows you to have various features in your application that help provide a good user experience. For example, providing exact location in the application, quick and easy integration, accuracy of data and deployment, and path enhancement, and elimination when no longer needed.
