PROSAGA码农传奇-时空索引-在OpenLayers上没有显示geojson图层

<div class =“post-text”itemprop =“text”>
  <P>
    您需要包含自定义投影（NAD83 / UTM区域17N（EPSG：26917））
  </p>
   <pre>
    <code>
      <script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.3/proj4.js"></script>
<script src="https://epsg.io/26917.js"></script>

var dataProjection = ol.proj.get('EPSG:26917');
var map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM()
    }),
    new ol.layer.Vector({
      title: 'added Layer',
      source: new ol.source.Vector({
        url: 'FLOOD_PLAIN.json.txt',
        format: new ol.format.GeoJSON({
          dataProjection: dataProjection,
          featureProjection: 'EPSG:3857'
        })
      })
    }),
    new ol.layer.Vector({
      title: 'added Layer',
      source: new ol.source.Vector({
        url: 'BUILDING_FOOTPRINT.json.txt',
        format: new ol.format.GeoJSON({
          dataProjection: dataProjection,
          featureProjection: 'EPSG:3857'
        })
      })
    })],
  view: new ol.View({
      center: ol.proj.fromLonLat([-80.981948,43.370172]),
      zoom: 14
  })
});

</code>
  </pre>
  <P>
    <a href="http://www.geocodezip.com/OL_5.3.0_GeoJSON_SO20190211.html" rel="nofollow noreferrer">
      概念证明
    </A>
  </p>
  <P>
    <a href="https://i.stack.imgur.com/H40jE.png" rel="nofollow noreferrer">
      <img src =“https://i.stack.imgur.com/H40jE.png”alt =“结果地图的截图”/>
    </A>
  </p>
</DIV>