Converting a point to screen geometry

JillianStanford

Hi All,

Ultimately what I'm trying to do is convert a map point to a screen point so that I can offset it by a distance in screen units and then convert it back to map point so I can place it on the map.

I'm trying to do this using the toMapGeometry and toScreenGeometry methods in the screenUtils module but they don't work as I expect them to.

Taking the offset out of the equation for a minute, what's confusing is that if I take a map point and convert it to a screen point and then convert it back to a map point again the X and Y are not the same as the original point. Shouldn't they be the same? Am I using these methods incorrectly?

Here's my code (for whatever reason syntax highlighting is not working for me today...):

var screenGeo = screenUtils.toScreenGeometry(this.map.extent, this.map.width, this.map.height, evt.geometry);

var mapPointGeo = screenUtils.toMapGeometry(this.map.extent, this.map.width, this.map.height, screenGeo);

//Ouput:

?evt.geometry

    type: "point"

    x: -88.18114353491255

    y: 41.7207439952267

?screenGeo

    type: "point"

    x: 64564

    y: 33899

?mapPointGeo

    type: "point"

    x: -83.94943230599165

    y: 98.94651940930635

I was expecting evt.geometry and mapPointGeo to be the same.

There are two other methods that are depreciated: toMapPoint and toScreenPoint. These do work as expected (once I do some geographic/web merc conversion).

Any ideas?

Thanks!

Jill

JillianStanford

Hi!

Thank you so much for all of the replies. I really appreciate it.

Robert, you are correct. The Map object's toScreen and toMap methods do give me the expected results. Thanks for the suggestion!

However, Bill, your comments made me reevaluate my strategy. You are right that tweaking the symbology gave me what I was looking for.

Thanks!

Jill