{"id":3622,"date":"2022-03-11T14:52:03","date_gmt":"2022-03-11T01:52:03","guid":{"rendered":"http:\/\/blogs.lincoln.ac.nz\/gis\/?p=3622"},"modified":"2023-05-07T02:46:41","modified_gmt":"2023-05-07T02:46:41","slug":"some-labels-are-better-than-others","status":"publish","type":"post","link":"https:\/\/blogs.lincoln.ac.nz\/gis\/some-labels-are-better-than-others\/","title":{"rendered":"Some labels are better than others"},"content":{"rendered":"

In this post we look at some clever contour labelling to make your maps sparkly with masking.<\/em><\/p>\n

We’ve been talking about map making in the GIS courses recently, which shouldn’t come as a surprise to anyone.\u00a0 Making effective maps to communicate your analysis results is an essential GIS skill.\u00a0 In one class we were looking at elevation contours and what they add to maps and got the point shown below for Quail Island:<\/p>\n

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I’m keeping this simple to illustrate a point but for now, I’ve chosen a colour and line thickness for the contours to roughly match what people are used to seeing on the 1:50,000 scale topomaps.\u00a0 Knowing that there’s an attribute called SPOT that has the elevation, it would be nice to label these so people know what each that is for each contour.\u00a0 Easy enough!<\/p>\n

With the Contours layer selected in the Contents pane, I’ve got a Labeling ribbon available:<\/p>\n

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With the Field set to SPOT and clicking the Label button, they appear on my map:<\/p>\n

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Not ideal – I’d much rather have the labels set up the way they would normally be – with the label in line with the contour.\u00a0 Towards the right of the ribbon there are some preset placements for labels, with Contours being among them (it’s on the second row):<\/p>\n

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Let’s try it – straight away an improvement, but still not great – they’ve just been plonked straight on top:<\/p>\n

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I’d like to remove the line underneath the contour value, like you would see on the topomaps:<\/p>\n

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(In an earlier post we talked about how to only label certain contours<\/a>.)<\/p>\n

My first thought was that I’ll use Halos to create this effect.\u00a0 This will use Symbology to make a sort of buffer around each of the labels.\u00a0 I’ll make\u00a0the halo the same colour as the background so it makes some space around each label:<\/p>\n

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(I cheated a little bit here – to get the colour exactly right, I used the Eyedropper in the Color drop down to match it:<\/p>\n

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That’s looking a bit more like it – until I turn on my Vegetation layer underneath:<\/p>\n

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That halo only works well when the background is always the same colour.\u00a0 There must be another way…\u00a0 There is!\u00a0 It’s a bit fiddly, but masking<\/a> is a way to make this work.\u00a0 Masking\u00a0allows us to\u00a0hide other features in a layer where there’s an overlap.\u00a0 We’ve got three steps to make this work:<\/p>\n