{"id":3102,"date":"2021-07-23T10:58:31","date_gmt":"2021-07-22T22:58:31","guid":{"rendered":"http:\/\/blogs.lincoln.ac.nz\/gis\/?p=3102"},"modified":"2023-05-07T02:59:27","modified_gmt":"2023-05-07T02:59:27","slug":"json-and-the-argonauts","status":"publish","type":"post","link":"https:\/\/blogs.lincoln.ac.nz\/gis\/json-and-the-argonauts\/","title":{"rendered":"JSON and the Argonauts"},"content":{"rendered":"

We look at extracting data from the Christchurch City Councils SmartView maps.<\/em><\/p>\n

As local government uses maps to make their data more and more available, we’ll look in this post at extracting some useful data from the Christchurch City Councils SmartView <\/a>maps.\u00a0 Let start with a quick look at what’s available:<\/p>\n

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You can type in an address int the Search window or click on one of the subsections – let’s go to Find section and see what’s there:<\/p>\n

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Clicking on any one of these takes you eventually to a map –\u00a0Fruit trees\u00a0look\u00a0interesting, yes?<\/p>\n

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This shows us locations and additional information if we click on a tree point. While this is great stuff, I might like to use this layer in my analysis, but in its current form, it is shackled to the browser.\u00a0 How could I extract it?<\/p>\n

I’ll admit at the start that I had no idea how to do this, let alone that SmartView was a thing until some of my ERST606 students brought it to my attention (hat tip to Estela and Grace, as well as the Argonauts<\/a>).\u00a0 There’s always something new to learn with GIS.\u00a0 Anyway, here’s how; gird your loins – it gets a bit involved.<\/p>\n

First navigate up to the top level page where we clicked on Find.\u00a0 Right-click somewhere\u00a0on the blue area\u00a0and choose “Inspect” – you’ll get a funny looking window at the right:<\/p>\n

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Select Network<\/strong> tab from the top menu and make sure XHR<\/strong> is selected:<\/p>\n

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On the SmartView page, click Find<\/strong> >\u00a0Fruit Tree<\/strong>s.\u00a0 In one of the windows, an item called “map_feature.php…” appears (NB – I had to use (gulp) Edge to do this – please don’t tell anyone I used Edge by choice<\/em>):<\/p>\n

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Right-click on this and choose ‘Copy link address’<\/p>\n

Paste this link in a new tab\u00a0 and\u00a0bunch of text appears:<\/p>\n

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Talk about gobbeldygook – what a mess.\u00a0 But there’s gold in them thar characters – on closer inspection, useful bits appear:<\/p>\n