A digital field guide is a modern electronic medium to help identify plants or wildlife, much like traditional field guides in book form. Based on photographs, text data, and even sound recordings, digital or electronic field guides provide information intended to better aid users without the need to carry heavy or bulky printed texts. Electronic field guides are, in short, electronic books or applications users download onto smart phones or other electronic devices such as tablet computer or a personal digital assistant (PDA).
Applications and digital guides include geographic or topic-specific content, offering users the ability to customize information specific to each users' preference or interest. For example, users might select an animal reference book, a bird reference book, or a nature book based on a specific city, country, or region. Each book or application has its own features and benefits, such as recordings of bird songs for bird reference books or photographs of leaves for plant identification. In terms of geographic specifics, users might choose a digital field guide with a broad regional reference such as Europe or a narrow regional scope such as London or Boston.
A typical digital field guide is not interactive, meaning it serves only as research and reference material with users determining identification based on photographs, text descriptions, and other data. Researchers continue to develop interactive applications that actively aid users with identification through object or sound recognition technologies. Users with appropriate digital field guide applications can take a photograph of a particular leaf or flower and have the application automatically identify the species based on a catalog of example photos and key characteristic markers. The application interprets user-generated photos or sound recordings, looking for key matching points to help in identification.
Various museums, universities, and national research centers across the globe continue to develop electronic field guide applications with more advanced capabilities. In the United States, the Smithsonian Institution in Washington, researchers at Columbia University, and the National Science Foundation each participate in research projects involving the development of a digital field guide with automatic recognition capabilities. Using specimens already available to these institutions, scientists take high resolution photographs to include in comparison catalogs and databases. As of 2009, the Smithsonian Institute recorded over 90,000 plant specimens, while researchers at Columbia recorded over 9,000 leaf examples for tree identification. Other researchers have cataloged dolphin dorsal fins for identification, recorded bird songs and calls for sound recognition, and created other plant and wildlife records for additional digital field guide applications.