1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.io;
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3 |
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4 | import java.io.StringWriter;
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5 | import java.math.BigDecimal;
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6 | import java.math.RoundingMode;
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7 | import java.util.HashMap;
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8 | import java.util.Iterator;
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9 | import java.util.Map;
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10 | import java.util.Map.Entry;
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11 |
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12 | import javax.json.Json;
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13 | import javax.json.JsonArrayBuilder;
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14 | import javax.json.JsonObjectBuilder;
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15 | import javax.json.JsonWriter;
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16 | import javax.json.stream.JsonGenerator;
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17 |
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18 | import org.openstreetmap.josm.data.Bounds;
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19 | import org.openstreetmap.josm.data.coor.EastNorth;
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20 | import org.openstreetmap.josm.data.coor.LatLon;
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21 | import org.openstreetmap.josm.data.osm.DataSet;
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22 | import org.openstreetmap.josm.data.osm.INode;
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23 | import org.openstreetmap.josm.data.osm.IRelation;
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24 | import org.openstreetmap.josm.data.osm.IWay;
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25 | import org.openstreetmap.josm.data.osm.Node;
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26 | import org.openstreetmap.josm.data.osm.OsmPrimitive;
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27 | import org.openstreetmap.josm.data.osm.Way;
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28 | import org.openstreetmap.josm.data.osm.visitor.PrimitiveVisitor;
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29 | import org.openstreetmap.josm.data.projection.Projection;
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30 | import org.openstreetmap.josm.gui.layer.OsmDataLayer;
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31 |
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32 | /**
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33 | * Writes OSM data as a GeoJSON string, using JSR 353: Java API for JSON Processing (JSON-P).
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34 | */
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35 | public class GeoJSONWriter {
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36 |
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37 | private final OsmDataLayer layer;
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38 | private final Projection projection;
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39 | private static final boolean skipEmptyNodes = true;
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40 |
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41 | /**
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42 | * Constructs a new {@code GeoJSONWriter}.
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43 | * @param layer The OSM data layer to save
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44 | * @param projection The projection to use for coordinates
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45 | */
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46 | public GeoJSONWriter(OsmDataLayer layer, Projection projection) {
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47 | this.layer = layer;
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48 | this.projection = projection;
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49 | }
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50 |
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51 | /**
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52 | * Writes OSM data as a GeoJSON string (prettified).
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53 | * @return The GeoJSON data
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54 | */
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55 | public String write() {
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56 | return write(true);
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57 | }
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58 |
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59 | /**
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60 | * Writes OSM data as a GeoJSON string (prettified or not).
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61 | * @param pretty {@code true} to have pretty output, {@code false} otherwise
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62 | * @return The GeoJSON data
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63 | * @since 6756
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64 | */
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65 | public String write(boolean pretty) {
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66 | StringWriter stringWriter = new StringWriter();
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67 | Map<String, Object> config = new HashMap<>(1);
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68 | config.put(JsonGenerator.PRETTY_PRINTING, pretty);
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69 | try (JsonWriter writer = Json.createWriterFactory(config).createWriter(stringWriter)) {
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70 | JsonObjectBuilder object = Json.createObjectBuilder()
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71 | .add("type", "FeatureCollection")
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72 | .add("crs", Json.createObjectBuilder().add("type", "name").add(
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73 | "properties", Json.createObjectBuilder().add("name", projection.toCode())))
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74 | .add("generator", "JOSM");
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75 | appendLayerBounds(layer.data, object);
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76 | appendLayerFeatures(layer.data, object);
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77 | writer.writeObject(object.build());
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78 | return stringWriter.toString();
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79 | }
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80 | }
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81 |
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82 | private class GeometryPrimitiveVisitor implements PrimitiveVisitor {
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83 |
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84 | private final JsonObjectBuilder geomObj;
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85 |
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86 | GeometryPrimitiveVisitor(JsonObjectBuilder geomObj) {
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87 | this.geomObj = geomObj;
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88 | }
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89 |
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90 | @Override
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91 | public void visit(INode n) {
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92 | geomObj.add("type", "Point");
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93 | LatLon ll = n.getCoor();
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94 | if (ll != null) {
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95 | geomObj.add("coordinates", getCoorArray(Json.createArrayBuilder(), n.getCoor()));
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96 | }
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97 | }
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98 |
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99 | @Override
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100 | public void visit(IWay w) {
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101 | geomObj.add("type", "LineString");
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102 | if (w instanceof Way) {
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103 | JsonArrayBuilder array = Json.createArrayBuilder();
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104 | for (Node n : ((Way) w).getNodes()) {
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105 | LatLon ll = n.getCoor();
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106 | if (ll != null) {
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107 | array.add(getCoorArray(Json.createArrayBuilder(), ll));
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108 | }
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109 | }
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110 | geomObj.add("coordinates", array);
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111 | }
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112 | }
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113 |
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114 | @Override
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115 | public void visit(IRelation r) {
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116 | // Do nothing
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117 | }
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118 | }
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119 |
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120 | private JsonArrayBuilder getCoorArray(JsonArrayBuilder builder, LatLon c) {
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121 | return getCoorArray(builder, projection.latlon2eastNorth(c));
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122 | }
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123 |
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124 | private static JsonArrayBuilder getCoorArray(JsonArrayBuilder builder, EastNorth c) {
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125 | return builder
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126 | .add(BigDecimal.valueOf(c.getX()).setScale(11, RoundingMode.HALF_UP))
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127 | .add(BigDecimal.valueOf(c.getY()).setScale(11, RoundingMode.HALF_UP));
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128 | }
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129 |
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130 | protected void appendPrimitive(OsmPrimitive p, JsonArrayBuilder array) {
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131 | if (p.isIncomplete()) {
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132 | return;
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133 | } else if (skipEmptyNodes && p instanceof Node && p.getKeys().isEmpty()) {
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134 | return;
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135 | }
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136 |
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137 | // Properties
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138 | final JsonObjectBuilder propObj = Json.createObjectBuilder();
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139 | for (Entry<String, String> t : p.getKeys().entrySet()) {
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140 | propObj.add(t.getKey(), t.getValue());
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141 | }
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142 |
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143 | // Geometry
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144 | final JsonObjectBuilder geomObj = Json.createObjectBuilder();
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145 | p.accept(new GeometryPrimitiveVisitor(geomObj));
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146 |
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147 | // Build primitive JSON object
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148 | array.add(Json.createObjectBuilder()
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149 | .add("type", "Feature")
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150 | .add("properties", propObj)
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151 | .add("geometry", geomObj));
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152 | }
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153 |
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154 | protected void appendLayerBounds(DataSet ds, JsonObjectBuilder object) {
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155 | if (ds != null) {
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156 | Iterator<Bounds> it = ds.getDataSourceBounds().iterator();
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157 | if (it.hasNext()) {
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158 | Bounds b = new Bounds(it.next());
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159 | while (it.hasNext()) {
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160 | b.extend(it.next());
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161 | }
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162 | appendBounds(b, object);
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163 | }
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164 | }
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165 | }
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166 |
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167 | protected void appendBounds(Bounds b, JsonObjectBuilder object) {
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168 | if (b != null) {
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169 | JsonArrayBuilder builder = Json.createArrayBuilder();
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170 | getCoorArray(builder, b.getMin());
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171 | getCoorArray(builder, b.getMax());
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172 | object.add("bbox", builder);
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173 | }
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174 | }
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175 |
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176 | protected void appendLayerFeatures(DataSet ds, JsonObjectBuilder object) {
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177 | JsonArrayBuilder array = Json.createArrayBuilder();
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178 | if (ds != null) {
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179 | for (Node n : ds.getNodes()) {
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180 | appendPrimitive(n, array);
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181 | }
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182 | for (Way w : ds.getWays()) {
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183 | appendPrimitive(w, array);
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184 | }
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185 | }
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186 | object.add("features", array);
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187 | }
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188 | }
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