topic Re: Labeling of decimals, rounding/padding using LabelLayer in ArcGIS JavaScript Maps SDK Questions

Labeling of decimals, rounding/padding using LabelLayer

ZoeZaloudek — Fri, 25 Sep 2015 15:35:58 GMT

I have a web map with a FeatureLayer (polygons). I’m using a LabelLayer to label the polygons with a double-type field. My values in the field go to the hundredth, but some don’t. (example image below) I want to show all labels with values to the tenth, which means some will have to be rounded, and others will have to be padded on the right with “.0”

I know how to do this in ArcMap - go to the layer’s attribute table, go to the field’s numeric properties, set how many decimal places to show, also check the ‘Pad with zeros’ box. How do I accomplish this with my web map? I can’t find a decimal places setting in the documentation for LabelLayer... Is there a round/pad function I can use in the textExpression of the addFeatureLayer method? Or is there a way to set field display properties in the map service?

Re: Labeling of decimals, rounding/padding using LabelLayer

TyroneBiggums — Fri, 25 Sep 2015 16:26:11 GMT

You can round up to the nearest tenth programmatically with Math.ceil10(yourValue, -1) if that helps. But, since the data is coming from a FeatureLayer that might not work out very well. Maybe this will at least steer you in the right direction.

Re: Labeling of decimals, rounding/padding using LabelLayer

TracySchloss — Mon, 28 Sep 2015 20:11:42 GMT

Have you looked at this section: Format info window content | Guide | ArcGIS API for JavaScript

I wonder if any of the techniques you can use for formatting infoWindows would work on a labelLayer?

Re: Labeling of decimals, rounding/padding using LabelLayer

KellyHutchins — Wed, 30 Sep 2015 17:01:49 GMT

Zoe Zaloudek You can do this using the LabelLayer class by specifying the number of places. Here's a jsbin that shows how to do this:

JS Bin - Collaborative JavaScript Debugging

And here's the relevant bit of code:

// Setup label properties

var statesLabels = new LabelClass({

labelExpressionInfo: {"value": "{AVE_FAM_SZ}"},

fieldInfos:[{

"fieldName": "AVE_FAM_SZ",

"format": {"places":2}

}]

});

// Apply label info to the feature layer

states.setLabelingInfo([statesLabels]);

Re: Labeling of decimals, rounding/padding using LabelLayer

TracySchloss — Wed, 30 Sep 2015 17:14:21 GMT

Does this work for FeatureLayers? The documentation specifically says ArcGISDynamicMapServiceLayer.

Re: Labeling of decimals, rounding/padding using LabelLayer

KellyHutchins — Wed, 30 Sep 2015 17:17:30 GMT

Tracy Schloss yes LabelClass works with FeatureLayers too. The example I posted is using a feature layer. We are currently working on updating the doc for labelling so at the next release it should be more clear.

Re: Labeling of decimals, rounding/padding using LabelLayer

ZoeZaloudek — Sat, 11 Dec 2021 07:46:52 GMT

Well, I got LabelClass to work, so I've partially succeeded. However, setting the fieldInfos>format>places doesn't seem to be doing the trick for me. Here's the code I implemented. The variables flayer, field and labelCDvSymbol are defined earlier in my code.

var labelsCDs = new LabelClass({labelExpressionInfo: {"value": "{"+field+"}"}, minScale: 10000000});
labelsCDs.fieldInfos = [{"fieldName": field, "format": {"places": 1}}]; 
labelsCDs.symbol = labelCDvSymbol;
console.log(labelsCDs);
fLayer.setLabelingInfo([labelsCDs]);

The labels show the correct field and font/symbol, but they're still just not rounded/padded to the tenth. I can see in the console that the fieldInfos>format>places has been set to 1.

Re: Labeling of decimals, rounding/padding using LabelLayer

KenBuja — Sat, 11 Dec 2021 07:46:55 GMT

Put that into the constructor of the LabelClass

var labelsCDs = new LabelClass({
    labelExpressionInfo: {"value": "{"+field+"}"}, 
    minScale: 10000000,
    fieldInfos: [{"fieldName": field, "format": {"places": 1}}],
    symbol: labelCDvSymbol
});  
console.log(labelsCDs);  
fLayer.setLabelingInfo([labelsCDs]);

You cannot set the properties of a class after it's been created. You have to use methods (which aren't available for this class).

Re: Labeling of decimals, rounding/padding using LabelLayer

ZoeZaloudek — Thu, 01 Oct 2015 19:34:18 GMT

Hm, I edited my code to match, but that still didn't do it. The label symbol looks different though.

It must be something else in my code that's messing it up. There's a lot more going on in addition to the label changes - changing symbology, text, etc. I figured out how to share on JS Bin (which I didn't even know about until I saw the examples that Kelly Hutchins posted-thanks!) and put the whole thing here:

JS Bin - Collaborative JavaScript Debugging

Re: Labeling of decimals, rounding/padding using LabelLayer

KenBuja — Thu, 01 Oct 2015 20:00:52 GMT

The problem was the version of the API. It works in v3.14, but not 3.13.

Re: Labeling of decimals, rounding/padding using LabelLayer

ZoeZaloudek — Thu, 01 Oct 2015 20:06:03 GMT

Aha! That was it! The labels round/pad correctly now. Thanks for digging into this with me!