topic Re: SimpleMarkerSymbol using meters in ArcGIS JavaScript Maps SDK Questions

SimpleMarkerSymbol using meters

Tom_Prutz — Wed, 27 Mar 2024 15:20:02 GMT

Good Afternoon

I am trying to create a cross on my map using a SimpleMarkerSymbol. This will be attached to the mouse pointer and is to be used for quick eyeball measuring. As such I need it to be a specific size e.g. 10 meters. I would like it to be a graphic that I can add to my graphics layer.

However the SimpleMarkerSymbol only takes sizes in pixels and points. Pixels can vary depending on the display equipment and I can't find any documentation to help me understand how points would relate to meters.

For other things like the Circle (https://developers.arcgis.com/javascript/latest/api-reference/esri-geometry-Circle.html) I can specify a radius in meters and then use a fill symbol to create a visual that matches the size. i.e. by specifying a radius of 5 meters and then add a Simple FillSymbol I end up with a visible 10 meter circle.

There isn't a cross equivalent of the circle (that I can find) and I can't provide a meter measurement to the only cross element I can find (the SimpleMarkerSymbol) so I'm at a bit of a loss as to how to achieve this. Should I be converting meters to points and if so what is the conversion rate? If not what is the recommended way to achieve this?

Any help or advice would be appreciated.

Re: SimpleMarkerSymbol using meters

JoelBennett — Wed, 27 Mar 2024 18:27:41 GMT

Rather than using a SimpleMarkerSymbol, you might try something like this:

Create a Circle with the 5 meter radius.
Using the circle's extent, determine the four endpoints for the cross.
Create a Polyline with 2 paths, one path being the vertical line, and one path being the horizontal line.
Create a Graphic with the polyline as the geometry, and a SimpleLineSymbol as the symbol.
Add the graphic to the view's graphics or some other GraphicsLayer.
Whenever the mouse moves:
1. Calculate the distance between the map location of the cursor and the center of the polyline's extent.
2. Translate the polyline so it's centered at the mouse's location.

Re: SimpleMarkerSymbol using meters

Tom_Prutz — Thu, 28 Mar 2024 14:07:11 GMT

Hi Joel

That worked really well thank you, problem solved.

I still find it a little weird that I can specify meters as a size option for my marker symbol but for now at least that doesn't matter.

Thank you very much for taking the time to post such a good solution!