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Using KML to Display Scientific Data in GoogleEarth. By Jim Graham May, 2008. Contents. How GoogleEarth Works Display Excel Data in GoogleEarth Creating KML Files for GoogleEarth. Section 1: How GoogleEarth Works. How GoogleEarth Works. Web Server. Local Computer. Internet.
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Using KML to Display Scientific Data in GoogleEarth By Jim Graham May, 2008
Contents • How GoogleEarth Works • Display Excel Data in GoogleEarth • Creating KML Files for GoogleEarth
How GoogleEarth Works Web Server Local Computer Internet Satellite Images GoogleEarth Spreadsheet Files KML Files
GoogleEarth • Created by Denver-based company, Keyhole • An application that runs on your computer • GIS Services for various layers • A system that you can add data to • Commercially owned
File Formats • Common file formats: • Word (*.doc) • PowerPoint (*.ppt) • Excel (*.xls)
GIS File Formats • Shapefiles • Coverages • GeoTIFF • Lots of others • Is KML a GIS format?
Keyhole Markup Language (KML) • Small Graphics Markup Language (SGML) • HyperText Markup Language (HTML) • Extensible Markup Language (XML)
Keyhole Markup Language (KML) • Based on XML • Very simple, flexible format • Can be create very complex files • Not an industry standard (could change at any time, only works in GoogleEarth) • KML Documentation: http://code.google.com/apis/kml/documentation/ • Or search on ‘KML’ into Google
GIS Data • Rasters (photos) • Satellite • Aerial • Vector Data • Points • Polylines/Paths • Polygons
Play with KML • Add Placemark • Add Path to and from somewhere • Add Polygon around your school • Save As… KML files
Situation • KML is still very new • Shapefiles are the most common GIS vector format • Converters are coming • Shapefiles are much more limited than KML files (i.e. it’s easy to go from Shapefile to KML, can be harder to go from KML to Shapefile)
Discussion Points • When should data be in a local file vs. on a web server? • What are the possible futures for KML? Web Server Local Computer Internet
Section 2: Displaying Excel Data in GoogleEarth • Problem: Display spreadsheet data in GoogleEarth • Solution: • Use an Excel “Add-In” that converts data in spreadsheets to a KML file • Open the KML file in GoogleEarth
Excel Add-Ins • Actually Excel files that include “Macros” • Hidden in your “Add-In” folder
WriteToKML AddIn • Install WriteToKML Add-In to your system • Make WriteToKML available to Excel • Add a custom tool to Excel • Use the tool to save a KML file • Make more interesting descriptions
Discussion Points • Discussion point: What type of data would you collect to make this work?
Section 3: Creating KML Files • The WriteToKML Add-In is limited • Does not support: • polygons and paths • Graphics • Icons • Lots of other features of KML • http://earth.google.com/kml/index.html
Creating KML Files • Simple text files without any formatting • Write in NotePad (TextEdit on the Mac), not MS-Word or other “word-processor”
Getting Started • Search on “KML” in Google • Click on “KML Documentation Introduction” • Click on “KML Tutorial” • Scroll down to light blue boxes • Copy everything in the box into a new NotePad file • Save as “text.kml”
Drag KML file into GoogleEarth • What is the approximate coordinate? • What is the name? • What is the description?
Writing KML Files • Open GoogleEarth and Notepad • Steps: • Edit in NotePad • Save to a file on the desktop • Double click on the file • Click “Yes” to reload and view the file • Repeat • Change name, description
“Simple” KML File with 1 Point <?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://earth.google.com/kml/2.2"> <Document> <Placemark> <name>Name of the Placemark</name> <description> Description appears in the balloon </description> <Point> <coordinates>102.595626,14.996729</coordinates> </Point> </Placemark> </Document> </kml>
Where to go from here • Multiple points • Add “Document” tags” • Add another point, save, view • Some fun stuff- Photos, paths, etc. • KML “Developer’s Guide” • KML Reference
Discussion Points • How would you use this in your classroom? • What types of data would kids find cool to put into GoogleEarth?
What is it you just did? • Web server/client architecture • Spatial Data File format: KML • Converting from Excel to KML • How to edit KML files