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<map-feature>

Map features are real or imaginary location objects represented in 2D according to a standard model, called the Simple Features model. There exists a wide variety of formats that allow the encoding of the Simple Features model, famously including: GeoJSON, Keyhole Markup Language (KML), and shape files (.shp), among many others.

Map features are represented in HTML MapML using a <map-feature> element, which is rendered on the map through translation to SVG. This allows the feature to scale without distortion, as you zoom in and out.

A <map-feature> element is a container for a feature's accessible name (<map-featurecaption>), scalar properties (<map-properties>) and its geometry (<map-geometry>). The <map-feature> element can be modeled as inline HTML content as a child of the <layer-> element, or in an XHTML MapML document, as a child of the <map-body> element.

Attributes​

zoom​

This allows you to set the zoom level the feature is rendered at. The zoom value should fall within the range of 0 to the maximum zoom level of the map's projection.

min​

The min (zoom) attribute gets or sets the native minimum zoom of the feature. Map features' geometry and other properties are scale-dependent. The min value is a rendering zoom value cut-off; at map zoom values less than min, the feature will not be rendered.

If min is not provided, a fallback value will be calculated; the fallback value will be the minimum zoom value of the layer, or if that is not specified, of the map viewer projection's minimum value i.e. 0.

max​

The max (zoom) attribute gets or sets the native maximum zoom of the feature. Map features' geometry and other properties are scale-dependent. The max value is a rendering zoom value cut-off; at map zoom values greater than max, the feature will not be rendered.

If max is not provided, a fallback value will be calculated; the fallback value will be the maximum zoom value of the layer, or if that is not specified, of the map viewer projection's maximum value e.g. 25 (depending on the projection).

Child Elements​

<map-featurecaption>​

This element contains the feature's accessible name, which is displayed when the feature is in focus or hovered.

<map-properties>​

This element contains the contents of the popup associated to a given feature. Details on the properties elements and it's syntax can be found here.

<map-geometry>​

This element contains the different points, lines and polygons that will be drawn. Details on the geometry elements and it's syntax can be found here.

Attributes​

  • cs
    • This allows you to set the coordinate system of geometries.
    • Defaults to pcrs (projected coordinates), but can be set to tilematrix | pcrs | gcrs explicitly.

Other elements may be important to provide context for feature data:

<map-meta name="zoom">​

Sets the native minimum and maximum native zoom. It also allows you to set a value, this is the default zoom of all features in the case the <map-feature> is missing a zoom attribute.

<map-meta name="zoom" content="min=1,max=5,value=0"></map-meta>

<map-meta name="projection">​

Sets the projection of the layer. 

<map-meta name="projection" content="CBMTILE"></map-meta>

<map-meta name="cs">​

Sets the default coordinate system of the layer. If a feature is missing the cs attribute it will 'fall back' to the value provided by a map-meta element, or pcrs if no map-meta element is in scope.

<map-meta name="cs" content="gcrs"></map-meta>

<map-meta name="extent">​

Sets the extent of the layer.

<map-meta name="extent" content="zoom=0,top-left-column=0,top-left-row=0,bottom-right-column=5,bottom-right-row=5"></map-meta>

Examples​

  <mapml-viewer projection="CBMTILE" zoom="2" lat="45.5052040" lon="-75.2202344"
    controls>

    <layer- label="Arizona" checked>
      <map-meta name="projection" content="CBMTILE"></map-meta>
      <map-meta name="zoom" content="min=1,max=5,value=0"></map-meta>
      <map-meta name="cs" content="gcrs"></map-meta>
      <map-meta name="extent" content="zoom=0,top-left-column=0,top-left-row=0,bottom-right-column=5,bottom-right-row=5"></map-meta>
      <map-link id="first" rel="stylesheet" type="text/css" href="first.css"></map-link>
      <map-feature zoom="2" class="refDiff">
        <map-properties>
          <h1>Test</h1>
          <a href="https://example.org/">test</a>
        </map-properties>
        <map-geometry cs="tilematrix">
          <map-polygon>
            <map-coordinates>11 11 12 11 12 12 11 12</map-coordinates>
          </map-polygon>
        </map-geometry>
      </map-feature>

      <map-feature zoom="2" class="refDiff">
        <map-properties>
          <h1>Test</h1>
        </map-properties>
        <map-geometry cs="pcrs">
          <map-polygon>
            <map-coordinates>257421 -3567196 -271745 1221771 -3896544 242811 -3183549 -2613313</map-coordinates>
          </map-polygon>
        </map-geometry>
      </map-feature>

      <map-feature zoom="2" class="refDiff">
        <map-properties>
          <h1>Test</h1>
        </map-properties>
        <map-geometry cs="tcrs">
          <map-polygon>
            <map-coordinates>2771 3106 2946 3113 2954 3210 2815 3192</map-coordinates>
          </map-polygon>
        </map-geometry>
      </map-feature>

      <map-feature zoom="2" class="refDiff">
        <map-properties>
          <h1>Arizona</h1>
        </map-properties>
        <map-geometry>
          <map-polygon>
            <map-coordinates>-109.042503 37.000263 -109.04798 31.331629 -111.074448 31.331629 -112.246513 31.704061
              -114.815198 32.492741 -114.72209 32.717295 -114.524921 32.755634 -114.470151 32.843265 -114.524921
              33.029481 -114.661844 33.034958 -114.727567 33.40739 -114.524921 33.54979 -114.497536 33.697668
              -114.535874 33.933176 -114.415382 34.108438 -114.256551 34.174162 -114.136058 34.305608 -114.333228
              34.448009 -114.470151 34.710902 -114.634459 34.87521 -114.634459 35.00118 -114.574213 35.138103
              -114.596121 35.324319 -114.678275 35.516012 -114.738521 36.102045 -114.371566 36.140383 -114.251074
              36.01989 -114.152489 36.025367 -114.048427 36.195153 -114.048427 37.000263 -110.499369 37.00574
              -109.042503 37.000263</map-coordinates>
          </map-polygon>
        </map-geometry>
      </map-feature>
    </layer->
  </mapml-viewer>

An inline HTML map-feature​

<layer- label="My Feature Layer" checked>
    <map-feature id="mem35059" zoom="17">
      <map-properties>
        <table>
          <tr><th>code</th><td>1200020</td></tr>
          <tr><th>accuracy</th><td>26</td></tr>
          <tr><th>valdate</th><td>1995</td></tr>          
          <tr>
            <th>image</th>
            <td>
              <a href="https://www.veterans.gc.ca/eng/remembrance/memorials/national-inventory-canadian-memorials/details/9304">
                <img src="https://www.veterans.gc.ca/images/remembrance/memorials/national-inventory-canadian-memorials/mem/35059-173a.jpg" width="60" height="60">
              </a>
            </td>
          </tr>
          <tr><th>theme</th><td>FO</td></tr>
          <tr><th>type</th><td>2</td></tr>
          <tr><th>elevation</th><td>61</td></tr>
          <tr><th>altiaccu</th><td>5</td></tr>
        </table>
      </map-properties>
      <map-geometry>
        <map-point>
          <map-coordinates>-75.705278 45.397778</map-coordinates>
        </map-point>
      </map-geometry>
    </map-feature>
</layer->

A map-feature in a fetched XHTML MapML document​

<layer- label="My Feature Layer" src="https://example.org/mem/35059.mapml"></layer->

35059.mapml:​

<mapml- lang="en" xmlns="http://www.w3.org/1999/xhtml">
  <map-head>
    <map-title>The Man With Two Hats</map-title>
    <map-meta http-equiv="Content-Type" content="text/mapml"></map-meta>
    <map-meta charset="utf-8"></map-meta>
    <map-meta name="projection" content="OSMTILE"></map-meta>
    <map-meta name="cs" content="gcrs"></map-meta>
    <map-link rel="license" href="https://open.canada.ca/en/open-government-licence-canada" title="Open Government License"/>
  </map-head>
  <map-body>
    <map-feature id="mem35059">
      <map-properties>
        <table>
          <tr><th>code</th><td>1200020</td></tr>
          <tr><th>accuracy</th><td>26</td></tr>
          <tr><th>valdate</th><td>1995</td></tr>          
          <tr>
            <th>image</th>
            <td>
              <a href="https://www.veterans.gc.ca/eng/remembrance/memorials/national-inventory-canadian-memorials/details/9304">
                <img src="https://www.veterans.gc.ca/images/remembrance/memorials/national-inventory-canadian-memorials/mem/35059-173a.jpg" width="60" height="60" />
              </a>
            </td>
          </tr>
          <tr><th>theme</th><td>FO</td></tr>
          <tr><th>type</th><td>2</td></tr>
          <tr><th>elevation</th><td>61</td></tr>
          <tr><th>altiaccu</th><td>5</td></tr>
        </table>
      </map-properties>
      <map-geometry>
        <map-point>
          <map-coordinates>-75.705278 45.397778</map-coordinates>
        </map-point>
      </map-geometry>
    </map-feature>
  </map-body>
</mapml->

Specifications​

Specification
MapML feature element

Requirements​

Report problems with these requirements on GitHub

requirementenhancementimpracticalundecidedunder discussion

SpecViewerAPI
Vector features and overlays (5.2)
Show pinpoint locations or custom markers on the map (5.2.1)
fullfull
Draw polygons or polylines as stylable, interactive vector graphics (separate from the image tiles) (5.2.2)
fullfull
User navigation (pan and zoom) (5.4)
Hide or show (and maybe dynamically load) vector features and labels on zoom (5.4.7)
fullexperimental
Custom styling (5.5)
Apply custom styling to map markers and vector features (5.5.1)
fulllimited