Much like estimating power consumption along a route many people would also like to answer the question “Where can I go?”. Typically you would place a pushpin on your map and draw a circle around the pin the radius of your distance you want to go. This circle method has a drawback though: The distance is a straight line distance and does not reflect the actual driving distance from a given point. As an EV driver with limited range the actual driving distance is more important to you. To that end I’ve created this driving circle page.

Enter in an address, or city name and a radius in miles and press “Calc Circle”. A transparent red circle will be drawn on the map. This circle is the linear distance from the given point. After about 20-30 seconds the green polygon will be drawn (I’ve had to put in some delays to prevent errors returned by Google). The polygon represents the area that can be driven to the given radius miles.

The polygon is calculated by dividing the circle up into 36 points. For each point the page requests directions from Google from the center to the point on the circle. It then walks the returned route stopping at the point when it hits the radius distance given. These end points are then used as vertices in the polygon.

Along a similar theme: Here is a version of the above page for drive times. On this page you enter in a location as above and the number of minutes you wish to drive (granted this page is more useful for going long distances). Here the red circle represents how far you would drive at 70 mph if you could drive in a straight line from the center point. The polygon is how far you’d go heading in that direction for the specified number of minutes. Again the circle is divided up into 36 points and Google is asked for directions from the center to each point. The vertices of the polygon are determined by following each route and calculating where you get at X minutes.

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