KML-Circles is an online app that creates open or filled polygons around a specified center point. With the default number of 60 vertices, you essentially create circles, but by selecting a small number, you can create other polygons (e.g. 3 for a triangle, 4 for a square), but with no control over their orientation. It operates in two different styles:
In Fixed style, you can specify an indefinite number of central points, and up to 15 different circle radii, each with its own selectable color:
# Vertices - Number of points used to draw polygon; the more points, the smoother the circle
Input - Either radius from the center, or diameter
Units - Metric (Meters, kilometers) and English (Miles, feet, yards)
Radius/Diameter - Sets the value for drawing the circles, in the units specified above. Circles are drawn in order from top to bottom, so it’s usually better to draw the larger circles first. Set the color for each radius by clicking on the “…” button.
Shape - LineStrings draws just the radius of the circle, Polygon draws it filled in.
Line Width - Sets line size in LineStrings mode.
Opacity - Sets opacity percentage (100% - fully opaque)
Altitude - Clamped to ground (default), Relative to ground and Absolute
Elevation - Sets value for Relative to ground and Absolute
Example 1 - Sample of fixed style (shown above)
Example 2 - Sample of variable style (shown below)
Clear - Clears position and radius/diameter data
Load File - You can load your own text data file into the input box; data can be separated by commas (CSV), spaces or tabs, with the Separator defined by the dropdown at upper right.
Create KML>> - Click on this button, and the specified data will be plotted in a Google Maps interface:
If you like the results, click on Download KML File and the KML code will be generated:
In Variable style, you can specify different sets of radii for different points, as in Example 2:
Up to 15 different radii can be used as input, with the “Column” dropdowns at left letting you specify the order in which the input radii are drawn:
GE-Path also creates circular polygons (in addition to grids and other useful shapes), but only one at a time. If you need to make multiple circles on a common radius at at the same time, KML-Circles is a convenient alternative.
Other posts in the Google Earth Data Tools series
- KML Editors
- Diagramming In Google Maps And Google Earth With Smoot
- Plotting Data In Google Earth Using GE-Graph
- Drawing Grids, Paths And Polygons In Google Earth Using GE-Path
- Online Google Earth Utilities For Buffering And Area Calculations
- Easy Display Of Thematic Data In Google Maps And Google Earth
- Using GIF/PNG Transparency In Displaying Raster Graphics In Google Earth
- Adding Vector Graphic Objects To Google Earth
- Animated GIFs In Google Earth
- Creating A Network KML Link To A Google Spreadsheet
- LIDAR Tools
- EarthPlot Software Tools For Google Earth
- Geographic Time Animations
- Convert TIGER Polygons To KML Files
- Putting Time Data Into A KML File
- Using The KML Time Embedder To Stamp Time Data Into A Google Earth File
- Using The KML Time Embedder, Concluded
- KML Time Embedder Improved With Hour-Minute-Second Ability
- Grid Creation And Path/Polygon Measurements: Two New Online KML Tools
- Google Earth PhotoOverlay Tool
- KML Random Placemark Generator
- Update For Online Google Earth Utilities
- KML Time Code Utility
- Screen Overlays In Google Earth
- The KML Screen Overlay Maker Utility
- KML Screen Overlay Maker Utility, Concluded
- KML Circle Generator
- Creating Google Earth Screen Overlays With EarthPaint
- Text Editor With KML Validation
- Online Spreadsheet To KML Converter
- Version 2.0 Of Google’s Online KML Spreadsheet Mapper Tool Released
- Creating Google Earth Ground Overlays From Georeferenced Images
- Google Earth Ground Overlays With GIF Transparency
- Creating "Transparent" Topo Map Overlays For Google Earth
- Using Google Earth Ground Overlays To Display Shapefile Data
- Converting 3D Objects Into Google Earth Format
- Thematic Mapping In Google Earth
- An Online KML Validator
- Modify A KML Polygon File With Excel Data
- US Nautical Chart Overlay For Google Earth
- Plot Google Analytics Geographic Data In Google Earth/Maps
- Placemark Creator For Google Earth
Last year we had a Foot and Mouth outbreak in the UK. The Govt created exclusion zones (500m diammeter) and controlled zones (10km) out from each occurence of the outbreak. Since the outbreaks were often on farms within less than the exclusion zone size an envelope of overlapping circles was created.
Could you create a solution to write only the external sections of the overlapping circles?
Thanks
GUY
I’m not the author of the KML Circle Generator, so I can’t help you on that front. But this is the sort of project that would literally take less than half-an-hour with even a basic free GIS like MapWindow or gvSIG.
1. Gather up the coordinates of all the farms into a single file of points (a point shapefile).
2. Use the buffer feature to draw circles of the right size around every farm.
3. Merge all of the circles into a single area (an area shapefile)
4. Convert that area shapefile into a KML file for viewing in Google Earth, using shp2kml.
If you can send me a file (spreadsheet or point shapefile) with the locations of the farms in question, the precise details of the exclusion zones, and the exact details of what you want, I can have a crack at it, and write up a step-by-step description of the process as a post. I’m always looking for good topics :).
Thanks, good post, KML-Circles is a handy tool! If you like to learn how to create basic shapes for Google Earth using KML and the Python programming language, take a look at “http://zoolboolcode.blogspot.com/2008/10/draw-simple-shapes-in-google-earth_09.html” for a basic introduction.