scatter3D 使用category（文本）作为一个数轴，Visualmap颜色映射存在问题echarts scatter3D配置项内容和展示

scatter3D 使用category（文本）作为一个数轴，Visualmap颜色映射存在问题

      var data = [
        ['Distance', 'RSSI', 'Mark'],
        [0.1, 1, 'corridor'],
        [0.2, 1.1, 'lobby'],
        [0.3, 1.2, '0'],
        [0.4, 1.3, '1'],
        [0.5, 1.4, 0],
        [0.6, 1.5, 1],
    ];
    var tips = ['corridor', 'lobby', '0', '1'];
    var colors = {        
        'corridor':'#ff4000', 'lobby':'#7f00ff',
        '0':'#0040ff', '1':'#ffbf00',
    }
    var _colors = [        
        '#ff4000', '#7f00ff',
        '#0040ff', '#ffbf00',
    ];

    option = {
        visualMap: [{
            top: 10,
            tooltip: {
                trigger: 'item'
            },
            type: 'piecewise',
            dimension: 2,
            categories: tips,
            inRange: {
                color: _colors,
            },
            textStyle: {
                color: '#000'
            }
        }],
        grid3D: {
        },
        xAxis3D: {
            name: 'Distance',
        },
        yAxis3D: {
            name: 'Mark',
            type: 'category',
            data: tips,
        },
        zAxis3D: {
            name: 'RSSI'
        },
        dataset: {
            dimensions: [
                'Distance',
                'RSSI',
                {
                    name: 'Mark',
                    type: 'ordinal'
                },
            ],
            source: data,
        },
        series: [{
                id: 'scatter3D',
                name: 'scatter3D',
                type: 'scatter3D',
                symbolSize: 3.5,
                encode: {
                    x: 'Distance',
                    y: 'Mark',
                    z: 'RSSI',
                    tooltip: [0, 1, 2],
                }
            },
        ],
        toolbox: {
            feature: {
                dataView: {},
            },
        },
    };

    myChart.setOption(option);