# 7.7. Defining Simple Feature Converters¶

A converter defines the mapping between input data and a SimpleFeatureType. Several of the command-line tools require the definition of a converter, for example to ingest data. See GeoMesa Convert for full details on creating converters.

GeoMesa commands support several different ways to define one (in order of priority):

1. the well-known name of a converter available on the classpath
2. the name of a file containing a TypeSafe configuration
3. a TypeSafe configuration as a string

## 7.7.1. Included Converters¶

GeoMesa distributions ship with converter definitions for several common data types including Twitter, GeoNames, T-drive, and more. See Prepackaged Converter Definitions for full details.

These converters are available via classpath loading, as described next. Available converters can be examined using the env command.

GeoMesa uses the TypeSafe Config library for loading converters from the classpath. Following convention, GeoMesa will load the default configuration, which is defined by the files reference.conf and/or application.conf. In the binary distributions, those files are included in the conf directory, with a variety of pre-defined types. See Prepackaged Converter Definitions for more information on the provided types.

Users can modify these files to define their own converters. By default, converters should be defined as objects under the path geomesa.converters. They are identified by their key.

See GeoMesa Convert for details on creating converters.

Once a converter has been defined on the classpath, it can be referenced by its well-known name, i.e. the object key under geomesa.converters. Available converters can be examined using the env command.

## 7.7.3. Configuration String¶

Instead of defining a converter configuration on the classpath, the same configuration string can be passed directly as an argument. Be careful to ensure the definition is still nested under geomesa.converters.

## 7.7.4. File Name¶

Instead of defining them directly on the command line, a converter can be defined in a file containing a configuration string. The file can then be referenced by name.