topic Re: Map Scale - New Feature in ArcGIS API for Silverlight Questions

Map Scale - New Feature

GISProgrammer — Thu, 15 Dec 2011 15:18:12 GMT

I was checking out the Map Scale
http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#MapScale
and I had a easy, silly question. Is it reporting the Display Units based on the map spatial ref? In the example the Spatial Reference: 102100 (3857) - Units: esriMeters? If yes is there a way to hard code the display units. Something similar to the scale bar (MapUnit="Meters" DisplayUnit="Miles"). I couldn't locate the any library ref.
Thanks

Re: Map Scale - New Feature

DominiqueBroux — Thu, 15 Dec 2011 15:53:35 GMT

A scale is a ratio and thus has no unit.
As a consequence, we don't need any DisplayUnits for reporting a scale (but for sure, the calculation of the scale is taking care of the spatial reference units).

Re: Map Scale - New Feature

GISProgrammer — Thu, 15 Dec 2011 16:11:07 GMT

Dom,

If I understand you correctly the example in the SDK is a spatial Reference: 102100 (3857) - Units: esriMeters so the scale is 'one centimetre to whatever number is displayed esriMeters' ????

I guess I'm thinking of scale as 1inch equals a Mile or 'one centimetre to one thousand kilometres'

Is this right? What is the expression in words for the example (as a ratio - it is showing a number so One ???? equals the displayed EsriMeters.

Is it possible to change the ratio units like 'one inch to one mile' or 1:63,360 or 1/63,360

Thanks

Re: Map Scale - New Feature

DominiqueBroux — Thu, 15 Dec 2011 16:48:23 GMT

If I understand you correctly the example in the SDK is a spatial Reference: 102100 (3857) - Units: esriMeters so the scale is 'one centimetre to whatever number is displayed esriMeters' ????

No. Looks like I was unclear.
You don't need to know that the SR is in meters.
A scale is the ratio of a distance on the map to the corresponding distance on the ground. It's not depending on the units.

A scale of 1:1000 means that 1 unit on the map equals 1000 units on the ground.
That's working whatever the units : 1 inch on the map = 1000 inches on the ground,
1cm on the map = 1000 cm on the ground, 1foot on the map equal 1000feet on the ground, ........

Re: Map Scale - New Feature

MuhammadWaqar_ul_islam — Fri, 23 Dec 2011 09:28:54 GMT

well i m trying to used Map scale my version of ARCGIS API 2.2 does it required 2.3

Re: Map Scale - New Feature

DominiqueBroux — Mon, 26 Dec 2011 09:25:28 GMT

well i m trying to used Map scale my version of ARCGIS API 2.2 does it required 2.3

You are right, map scale support has been introduced in 2.3.