kmz2struct

A function to load KML/KMZ files as MATLAB structures.

About

This function converts KML and KMZ files into a MATLAB structure. If converting a KMZ file, this function extracts the KMZ to a directory called '.kml2struct' in the home directory. This directory is deleted when the function exits.

The output of this function is similar to the MATLAB shaperead. It also adds fields for:

• Folder - The KML folder where the shape exists.
• Color - The color of the shape as a three element row vector in RGB format.

This function only handles KML/KMZ files with Point, LineString, and Polygon geometries. If this function is used to read a KML/KMZ with other elements, they are omitted from the result.

Installation

The easiest way to install this function is to download it from the link below then add the kmz2struct.m file to your matlab path.

Usage

To load a KML/KMZ file with this function, use the function like this:

S = kmz2struct(filename)

• filename - The full or relative path to KML/KMZ file you wish to load.
• S - The data loaded from the KML/KMZ file in MATLAB structure format.

If a MATLAB table is preferred, use the MATLAB struct2table function:

S = kmz2struct(filename)
T = struct2table(S)

• T - The data loaded from the KML/KMZ file as MATLAB table object.

Development Strategy

The kmz2struct function performs the following steps:

• Unzip KMZ Files - If filename is a KMZ file, the kmz2struct function unzips it to the .kmz2struct folder in the user's home directory.
• Loop Through KML Files Within The Unzipped folder - Loop through the unzipped folder and find the KML files. If a KML file is provided no looping is required.
• Load Each KML File As A DOM - Use the MATLAB xmlread function to load the KML file as a Document Object Model (DOM). This method is slightly slower than attempting to load the file with a regular expression, but this method makes it easier to track the folder for each geometry.
• Load All the Styles From The KML - Load all the styles from the KML. KML styles contain the colors that need to be linked to geometries later.
• Recursively Search The KML Folders For Geometries - Search the KML file for geometries recursively. Track the folder in which each geometry is found.
• Load Each Geometry - Load each geometry found from the DOM into a structure. Link the geometry to a style to find the color.
• Use A Regular Expression To Read In Coordinates - Use a regular expression to read in coordinates. This is a much faster way load to coordinates in. Add coordinates to the structure.
• Combine The Structure From Each Geometry - Combine all the structures to output a structure array.

Future Improvements

• Load more types of KML/KMZ data.
• Use regular expressions to improve the performance of part or all of the kmz2struct function.
• Matpak integration?

Feel free to open a pull request!