Convert MID to KML

Understanding MID and KML file formats

MID files, or MapInfo Interchange Format files, are used to store attribute data associated with geographic features in MapInfo software. They are typically paired with MIF (MapInfo Interchange Format) files, which contain the actual spatial data. Together, MIF and MID files allow for the exchange of geospatial data between different GIS applications.

KML (Keyhole Markup Language) is an XML-based file format developed by Google for displaying geographic data in Earth browsers such as Google Earth and Google Maps. KML files can represent points, lines, polygons, and images, making them a popular choice for sharing and visualizing geospatial information.

Why convert MID to KML?

Converting MID (with its paired MIF) to KML allows you to visualize and share your geospatial data in widely used platforms like Google Earth. This enhances accessibility and presentation of your geographic information.

How to convert MID to KML

Since MID files are always used together with MIF files, you must have both files for a successful conversion. The conversion process involves reading the spatial data from the MIF file and the attribute data from the MID file, then exporting the combined data to a KML file.

Best software for MID to KML conversion

QGIS (Quantum GIS) is a powerful, free, and open-source GIS application that supports both MapInfo and KML formats. Here’s how to convert MID/MIF to KML using QGIS:

1. Open QGIS and go to Layer → Add Layer → Add Vector Layer.
2. Select your MIF file (ensure the MID file is in the same directory).
3. Once loaded, right-click the layer and choose Export → Save Features As....
4. In the Format dropdown, select KML.
5. Choose the output file location and click OK to export.

Other notable tools include GDAL/OGR (using the ogr2ogr command-line utility) and FME (Feature Manipulation Engine), which offer advanced conversion capabilities for batch processing and automation.

Key considerations

• Always ensure both the MIF and MID files are present and correctly paired.
• Check the attribute mapping after conversion to ensure all data is preserved.
• KML files may have limitations on attribute complexity compared to MapInfo formats.

Summary

Converting MID/MIF to KML is essential for sharing geospatial data in Google Earth and similar platforms. QGIS is the recommended free tool for this conversion, offering a straightforward workflow and robust support for both formats.