topic Re: Buffer around all geometries in ArcGIS JavaScript Maps SDK Questions

Buffer around all geometries

DanielWebb2 — Fri, 22 Aug 2014 23:58:44 GMT

I’m looking to create one buffer around multiple graphics.

The user clicks the desired polygons, which creates graphics matching the geometry of the polygons. After certain ones are picked I want to buffer around all of those with the same shape they all have together. Below is the code I’m trying for the buffer.

It always break on gsvc.buffer(params, showBuffer); which makes me think there’s a problem with the params.

var geom = new Graphic();

geom = graphicsLayer.graphics;

var selectedGeom = graphicsUtils.getGeometries(geom);

var bufferDist = Math.floor(dom.byId("txtBufferDist").value);

var params = new BufferParameters();

params.geometries = [selectedGeom];

params.distances = [bufferDist];

params.unit = GeometryService.UNIT_FOOT;

params.outSpatialReference = bcMap.spatialReference;

gsvc.buffer(params, showBuffer);

function showBuffer(){

//Code

}

HOWEVER, if I use graphicsUtils.graphicsExtent instead of graphicsUtils.getGeometries it works. But I don’t want a square every time. I want the buffer to follow the outline shape as seen in yellow.

Thanks for any help.

Re: Buffer around all geometries

RobertScheitlin__GISP — Sat, 23 Aug 2014 05:07:04 GMT

Daniel,

So it looks like your issue is that graphicUtil.getGeometries returns an array and you then are putting that array inside another array here:

params.geometries = [selectedGeom];

Try:

params.geometries = selectedGeom;

You also are start the geom var as a Graphics and then overwrite it with an array of Graphics:

var geom = new Graphic();
geom = graphicsLayer.graphics;

This is no big deal as you are overwriting it but there is no need to start it as a Graphic and then set it to an Array. This would make more sense:

var graphics = graphicsLayer.graphics;
var selectedGeoms = graphicsUtils.getGeometries(graphics);

Re: Buffer around all geometries

DanielWebb2 — Tue, 26 Aug 2014 21:24:20 GMT

Thanks a ton! That basically got it. Now it makes a graphic around each polygon. This at least gets past my wall gives me something else to look into. I’m hoping to get one single graphic as a buffer.

Thanks again.

Re: Buffer around all geometries

RobertScheitlin__GISP — Tue, 26 Aug 2014 21:29:07 GMT

Daniel,

for that you just need to set the unionResults to true for the BufferParameters

Re: Buffer around all geometries

DanielWebb2 — Tue, 26 Aug 2014 21:47:09 GMT

You rock! It was so simple! Now I feel dumb for missing that property. I was trying to figure how to make esri/dijit/editing/Union or esri/dijit/analysis/MergeLayers work.

Thanks for your help.