topic Re: Drawing a circle around a point in ArcGIS API for Flex Questions

Drawing a circle around a point

TomRauch — Sat, 19 Jan 2013 00:25:04 GMT

Hi, I would like some help understanding how to draw a circle showing the perceived radius of an earthquake (from a value held in my database) with the epicenter at the center of the circle. For example, an earthquake with a magnitude of 4.6 could have a perceived radius of 50+ miles. I would like to show that radius as a colored circle with no fill, if that makes sense.

Thanks, Tom

Re: Drawing a circle around a point

RobertScheitlin__GISP — Sat, 19 Jan 2013 00:35:56 GMT

Tom,

Look at the buffer sample:

http://resources.arcgis.com/en/help/flex-api/samples/01nq/01nq0000002q000000.htm

Re: Drawing a circle around a point

TomRauch — Mon, 21 Jan 2013 12:59:42 GMT

Hi Robert, I did look at the buffer sample but am still stumped. I am not sure what the 'polylines' refer to in the buffer.geometries lines, I suspect these are important but not sure how to use them to drive a circle with a radius that comes from a variable I set.

Thanks, Tom

Re: Drawing a circle around a point

RobertScheitlin__GISP — Mon, 21 Jan 2013 14:34:10 GMT

Tom,

If you look at the sample it is buffering polylines, that is what the lines are about. There is not a specific sample that buffers points. But the concept is identical just feed the project function MapPoint geometry instead of a polyline. You can also download and look at specific code for buffering point geometries from my point buffer widget.

http://www.arcgis.com/home/item.html?id=a950162cd17a4acc985132d40adfe38f

Re: Drawing a circle around a point

AndyGup — Tue, 22 Jan 2013 17:21:40 GMT

Tom,

Not sure if this is exactly what you need, but attached is an ActionScript library that shows various methods for drawing a circle on the client using radius as an input property.

-Andy

Re: Drawing a circle around a point

stevemclaughlin — Tue, 19 Feb 2013 14:06:06 GMT

This is great, thanks Andy!