如何从php转换geojson中的几何图形并在postgis中插入多边形

Question

我是 postgis 和 geojson 的初学者，

我应该从 geojson 中提取每个几何图形并将它们作为多边形存储在 postgis 数据库中

对于 geojson 中的每个条目，我希望能够将其几何图形单独存储在数据库中，就像它在 json 中一样

在数据库中几何类型是：

ALTER TABLE public.a_final ADD COLUMN geometry geometry (Polygon, 4326);

到目前为止我做了什么：

$geojson = file_get_contents("o/1.geojson");
//echo $geojson;
$array = json_decode($geojson, TRUE);

echo "<pre>";
print_r($array);
echo "</pre>";    


foreach($array['features'] as $type){

    $layer = $type['properties']['Layer'];
    $SubClasses = $type['properties']['SubClasses'];
    $ExtendedEntity = $type['properties']['ExtendedEntity'];
    $Linetype = $type['properties']['Linetype'];
    $EntityHandle = $type['properties']['EntityHandle'];
    $Text = $type['properties']['Text'];
    $geometry = $type['geometry'];




}

GeoJSON：

Array
(
    [type] => FeatureCollection
    [features] => Array
        (
            [0] => Array
                (
                    [type] => Feature
                    [properties] => Array
                        (
                            [Layer] => Green Area
                            [SubClasses] => AcDbEntity: AcDbPolyline
                            [ExtendedEntity] =>
                            [Linetype] =>
                            [EntityHandle] => 6B
                            [Text] =>
                        )

                    [geometry] => Array
                        (
                            [type] => LineString
                            [coordinates] => Array
                                (
                                    [0] => Array
                                        (
                                            [0] => 708305.979
                                            [1] => 385139.794
                                        )

                                    [1] => Array
                                        (
                                            [0] => 708433.3
                                            [1] => 384989.4
                                        )

                                    [2] => Array
                                        (
                                            [0] => 708434.8
                                            [1] => 384987.7
                                        )

                                    [3] => Array
                                        (
                                            [0] => 708400.454
                                            [1] => 384958.526
                                        )

                                    [4] => Array
                                        (
                                            [0] => 708259.989
                                            [1] => 385100.729
                                        )

                                    [5] => Array
                                        (
                                            [0] => 708305.979
                                            [1] => 385139.794
                                        )

                                )

                        )

                )

            [1] => Array
                (
                    [type] => Feature
                    [properties] => Array
                        (
                            [Layer] => Green Area
                            [SubClasses] => AcDbEntity: AcDbPolyline
                            [ExtendedEntity] =>
                            [Linetype] =>
                            [EntityHandle] => 6C
                            [Text] =>
                        )

                    [geometry] => Array
                        (
                            [type] => LineString
                            [coordinates] => Array
                                (
                                    [0] => Array
                                        (
                                            [0] => 702461.518
                                            [1] => 381980.706
                                        )

                                    [1] => Array
                                        (
                                            [0] => 702436.783
                                            [1] => 381924.255
                                        )

                                    [2] => Array
                                        (
                                            [0] => 702427.496
                                            [1] => 381927.398
                                        )

                                    [3] => Array
                                        (
                                            [0] => 702452.871
                                            [1] => 381985.312
                                        )

                                    [4] => Array
                                        (
                                            [0] => 702461.518
                                            [1] => 381980.706
                                        )

                                )

                        )

                )

Answer 1

您不需要完成将 GeoJSON 转换为 SQL 的所有繁重工作，您可以使用 ST_GeomFromGeoJSON() 将其简单地丢给 PostgreSQL。然后，您只需做一些事情，例如：

<?php
//load GeoJSON
$geojson = file_get_contents("o/1.geojson");
//Translate that into JSON-compliant array of features
$features = json_decode($geojson, TRUE)->features;
//Connect to your database
$connection = pg_connect(....);
//Iterate over features within FeatureCollection
foreach($features as $feature) {
    //Extract necessary attributes
    $layer = $feature->properties["Layer"];
    $subClasses = $feature->properties["SubClasses"];
    ....
    //Extract geometry attribute as a string
    $geomJson = json_encode($feature->geometry);
    //Make up SQL-query
    $sql = "insert into mytable (layer, subclasses, ...., geom) values ('".$layer."','".$subClasses."',..., st_geomfromgeojson('".$geomJson."')";
    //Execute the query
    pg_query($connection, $sql);
}
?>