topic Re: Coordinate Widget in ArcGIS Viewer for Flex Questions

Coordinate Widget

JoshuaCoates — Fri, 22 Oct 2010 19:42:03 GMT

I successfully added the coordinate widget to my flex map and am just trying to find out why the values are so large for the Lat. & Long.? The CoordinateWidget.xml looks like this:

<configuration>
    <!-- geo, dms, mercator -->
    <outputunit>geo</outputunit>
    <numberformatter precision="6"/>
    <label template="Latitude:{1}   Longitude:{0}"/>
</configuration>

For some reason, this county that is in Georgia has lat/long values that are HUGE....lat:1526227.083333 & long:2062602.444444. Why are the lat/long 7 numbers before the decimal? Shouldnt it be lat:34 and long:-84 or something around there??

Thanks,
Josh C.

Re: Coordinate Widget

RobertScheitlin__GISP — Fri, 22 Oct 2010 20:02:32 GMT

Josh,

Webmercator is UTM not geographic so those values are correct since Webmercator coordinates are in meters.

Re: Coordinate Widget

DasaPaddock — Fri, 22 Oct 2010 21:37:11 GMT

If the spatial reference of your map is web mercator, then it will convert to geographic. Try running config-all.xml for an example.

If the spatial reference of your map is geographic, then no conversion is required, but if it's something else, you won't see geographic values.

Re: Coordinate Widget

JoshuaCoates — Mon, 25 Oct 2010 11:56:53 GMT

It is actually Tranverse Mercator, State Plane...So i suppose this is how it is going to show the latitude and longitude...in meters? No big deal, I am not sure why I thought it might show degrees of latitude and longitude. Thanks for your clarification!

Josh C.

Re: Coordinate Widget

JoshuaCoates — Mon, 25 Oct 2010 18:07:53 GMT

If the spatial reference of my map is transverse mercator, is there not a way that the coordinate widget can convert to decimal degrees and show DD for the lat./long.? Is seems like this is something that should be manageable....

Re: Coordinate Widget

RobertScheitlin__GISP — Mon, 25 Oct 2010 18:16:05 GMT

Joshua,

The client side code does not have the ability to re-project coordinates from StatePlane to geographic natively. ESRI probably will not add client side re-projection to the API as the API is free and that would be a significant investment of man-hours to do and then to maintain.

Re: Coordinate Widget

JoshuaCoates — Mon, 25 Oct 2010 18:38:03 GMT

Ok, thanks. So it is just going to have to be shown in meters then?! I didnt know if it was possible that the coordinate widget could just convert from stateplane to decimal degrees. I had no idea that it would have to completely re-project the map. I just thought there were equivalent values from stateplane that could be converted to the decimal degree location?!

Re: Coordinate Widget

RobertScheitlin__GISP — Mon, 25 Oct 2010 18:52:38 GMT

Joshua,

Yes it would just have to re-project the point coordinate of the mouse and not the map, but that still leads to the fact that the client side code does not know how to do this, and it would take a round trip to the server every pixel that the mouse move in order to do this.

Re: Coordinate Widget

JayGeisen — Tue, 26 Oct 2010 17:52:14 GMT

Dasa/Robert,

Wouldn't it be possible to have a tool that would only re-project to geographic values on mouse click only instead of continuously? How difficult would this be to do? Does this exist already?

Thanks,
Jay