按年分组的传单滑块

Question

我正在使用传单滑块 - https://github.com/dwilhelm89/LeafletSlider - 但我得不到想要的结果，即使从插件描述看来它可以做到。

我有一个特征集合，几何类型是多边形，我根据插件的要求插入了一个属性 "time"。我已经尝试使用 "time":"2014" 和 "time":"2014-01-01 00:00:00" 进行机器人操作，但没有任何区别。我总共有 30 个功能，2012 年有 10 个，2013 年有 10 个，2014 年有 10 个

我想要实现的是显示 2012 年的所有多边形，然后是 2013 年，然后是 2014 年，通过移动滑块，应该有 3 个步骤，每年一个步骤。

相反，每次滑块移动时我总是得到一个多边形。一开始我也得到了所有的多边形 (30) 设计在彼此之上，即使我指定“showAllOnStart: false”

这是我的 js 代码：

var geojson;
    $(document).ready(function () {
        $.getJSON("urlWhereIretrieveTheJson", function (geoJson) {
            geojson = L.geoJson(geoJson, { style: style, onEachFeature: onEachFeature }).addTo(map);

            var sliderControl = L.control.sliderControl({
                position: "bottomleft",
                layer: geojson,
                range: false,
                showAllOnStart: false
            });

            map.addControl(sliderControl);
            sliderControl.startSlider();
            ;
        });
    });

json 架构如下所示：

{"type": "FeatureCollection",
"features": [
{"type":"Feature",
"properties": {"name": "Thies","bl": 6,"**time**": "**2013-01-01 00:00:00+00**"},
"geometry":{"type":"Polygon","coordinates":[....]} 
},{....}
]}

这是一个带有完整代码和数据源的jsFiddle： http://jsfiddle.net/brainsengineering/nboo4ksg/

Answer 1

一件事的答案

即使我指定"showAllOnStart: false"

，我也得到了所有设计在彼此之上的多边形（30）

你是这样添加的geojson

geojson = L.geoJson(geoJson, { style: style, onEachFeature: onEachFeature }).addTo(map);

不要在最后加addTo(map)，直接这样

geojson = L.geoJson(geoJson, { style: style, onEachFeature: onEachFeature });

另一件事是您想根据相同的值对数据进行分组，即 2013、2014 和 2015 年的分组数据。为此，我们需要更改插件 a位，因为目前插件不处理基于相同值的数据分组。所以这是代码

L.Control.SliderControl = L.Control.extend({
options: {
    position: 'topright',
    layers: null,
    timeAttribute: 'time',
    isEpoch: false,     // whether the time attribute is seconds elapsed from epoch
    startTimeIdx: 0,    // where to start looking for a timestring
    timeStrLength: 19,  // the size of  yyyy-mm-dd hh:mm:ss - if millis are present this will be larger
    maxValue: -1,
    minValue: -1,
    showAllOnStart: false,
    markers: null,
    range: false,
    follow: false,
    alwaysShowDate : false,
    rezoom: null
},

initialize: function (options) {
    L.Util.setOptions(this, options);
    this._layer = this.options.layer;

},

extractTimestamp: function(time, options) {
    if (options.isEpoch) {
        time = (new Date(parseInt(time))).toString(); // this is local time
    }
    return time.substr(options.startTimeIdx, options.startTimeIdx + options.timeStrLength);
},

setPosition: function (position) {
    var map = this._map;

    if (map) {
        map.removeControl(this);
    }

    this.options.position = position;

    if (map) {
        map.addControl(this);
    }
    this.startSlider();
    return this;
},

onAdd: function (map) {
    this.options.map = map;

    // Create a control sliderContainer with a jquery ui slider
    var sliderContainer = L.DomUtil.create('div', 'slider', this._container);
    $(sliderContainer).append('<div id="leaflet-slider" style="width:200px"><div class="ui-slider-handle"></div><div id="slider-timestamp" style="width:200px; margin-top:13px; background-color:#FFFFFF; text-align:center; border-radius:5px;"></div></div>');
    //Prevent map panning/zooming while using the slider
    $(sliderContainer).mousedown(function () {
        map.dragging.disable();
    });
    $(document).mouseup(function () {
        map.dragging.enable();
        //Hide the slider timestamp if not range and option alwaysShowDate is set on false
        if (options.range || !options.alwaysShowDate) {
            $('#slider-timestamp').html('');
        }
    });

    var options = this.options;
    this.options.markers = [];
    this.options.unique_time_values = [];

    //If a layer has been provided: calculate the min and max values for the slider
    if (this._layer) {
        /*var index_temp = 0;
        this._layer.eachLayer(function (layer) {
            //console.log(layer);
            options.markers[index_temp] = layer;
            ++index_temp;
        });
        options.maxValue = index_temp - 1;
        this.options = options;*/

        var flags = [], unique_values = [],len;
        this._layer.eachLayer(function (layer) {

            if( flags[layer.feature.properties.time]) return;
            flags[layer.feature.properties.time] = true;
            unique_values.push(layer.feature.properties.time);
            ++len;

        });
        //console.log(unique_values);

        var all_features = [];
        for (var i=0;i<unique_values.length;i++){
            all_features[i] = [];
        }
        //console.log(all_features);

        //console.log(this._layer.getLayers().length)
        var layers = this._layer.getLayers()
        for(var i=0;i<layers.length;i++){

            //console.log(layers[i].feature.properties.time);
            var index = unique_values.indexOf(layers[i].feature.properties.time)
            //console.log(index);
            all_features[index].push(layers[i]);

        }
        //console.log(all_features);

        for (var i=0;i<all_features.length;i++){
            options.markers[i] = L.featureGroup(all_features[i]);
        }
        options.maxValue = all_features.length - 1;
        this.options = options;
        this.options.unique_time_values = unique_values

    } else {
        console.log("Error: You have to specify a layer via new SliderControl({layer: your_layer});");
    }
    return sliderContainer;
},

onRemove: function (map) {
    //Delete all markers which where added via the slider and remove the slider div
    for (i = this.options.minValue; i < this.options.maxValue; i++) {
        map.removeLayer(this.options.markers[i]);
    }
    $('#leaflet-slider').remove();
},

startSlider: function () {
    _options = this.options;
    _extractTimestamp = this.extractTimestamp
    var index_start = _options.minValue;
    if(_options.showAllOnStart){
        index_start = _options.maxValue;
        if(_options.range) _options.values = [_options.minValue,_options.maxValue];
        else _options.value = _options.maxValue;
    }
    $("#leaflet-slider").slider({
        range: _options.range,
        value: _options.minValue,
        values: _options.values,
        min: _options.minValue,
        max: _options.maxValue,
        step: 1,
        slide: function (e, ui) {
            var map = _options.map;
            var fg = L.featureGroup();
            if(!!_options.markers[ui.value]) {
                //console.log('inside');
                // If there is no time property, this line has to be removed (or exchanged with a different property)
                if(_options.markers[ui.value].feature !== undefined) {
                    if(_options.markers[ui.value].feature.properties[_options.timeAttribute]){
                        if(_options.markers[ui.value]) $('#slider-timestamp').html(
                            _extractTimestamp(_options.unique_values[ui.value].feature.properties[_options.timeAttribute], _options));
                    }else {
                        console.error("Time property "+ _options.timeAttribute +" not found in data");
                    }
                }else {
                    // set by leaflet Vector Layers
                    if(_options.unique_time_values[ui.value]){
                        if(_options.markers[ui.value]) $('#slider-timestamp').html(
                            _extractTimestamp(_options.unique_time_values[ui.value], _options));
                    }else {
                        console.error("Time property "+ _options.timeAttribute +" not found in data");
                    }
                }

                var i;
                // clear markers
                for (i = _options.minValue+1; i <= _options.maxValue; i++) {
                    if(_options.markers[i]) map.removeLayer(_options.markers[i]); 
                }
                if(_options.range){
                    // jquery ui using range
                    for (i = ui.values[0]; i <= ui.values[1]; i++){
                       if(_options.markers[i]) {
                           map.addLayer(_options.markers[i]);
                           fg.addLayer(_options.markers[i]);
                       }
                    }
                }else if(_options.follow){
                    for (i = ui.value - _options.follow + 1; i <= ui.value ; i++) {
                        if(_options.markers[i]) {
                            map.addLayer(_options.markers[i]);
                            fg.addLayer(_options.markers[i]);
                        }
                    }
                }else{
                    for (i = _options.minValue; i <= ui.value ; i++) {
                        if(_options.markers[i]) {
                            map.addLayer(_options.markers[i]);
                            fg.addLayer(_options.markers[i]);
                        }
                    }
                }
            };
            if(_options.rezoom) {
                map.fitBounds(fg.getBounds(), {
                    maxZoom: _options.rezoom
                });
            }
        }
    });
    if (!_options.range && _options.alwaysShowDate) {
        $('#slider-timestamp').html(_extractTimeStamp(_options.markers[index_start].feature.properties[_options.timeAttribute], _options));
    }
    for (i = _options.minValue; i < index_start; i++) {
        _options.map.addLayer(_options.markers[i]);
    }
}
});

L.control.sliderControl = function (options) {
    return new L.Control.SliderControl(options);
};

只需删除插件当前源的 link 并使用上面提供的代码代替插件文件即可。如果您遇到任何问题，请告诉我，我也会为您创建一个 fiddle。

注意：由于我已经针对您的具体情况修改了代码，因此在其他情况下可能无法正常工作

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