postgresql 拼接线geojson

场景：有2个经纬度。4个字段，拼接线geojson 

SELECT
    json_build_object(
        'type', 'Feature',
        'geometry', ST_AsGeoJSON(
            ST_MakeLine(
                ST_SetSRID(ST_MakePoint(ST_X(ST_Transform(ST_SetSRID(ST_Point(startpty::float, startptx::float), 4549), 4326))-0.75, 
                            ST_Y(ST_Transform(ST_SetSRID(ST_Point(startpty::float, startptx::float), 4549), 4326))), 4326),
                ST_SetSRID(ST_MakePoint(ST_X(ST_Transform(ST_SetSRID(ST_Point(endpty::float, endptx::float), 4549), 4326))-0.75, 
                            ST_Y(ST_Transform(ST_SetSRID(ST_Point(endpty::float, endptx::float), 4549), 4326))), 4326)
            )
        )::json,
        'properties', json_build_object(
            'pipelinetype',pipelinetype,
'startptx',startptx,
'startpty',startpty,
'endptx',endptx,
'endpty',endpty,
'startno',startno,
'endno',endno,
'startdeep',startdeep,
'enddeep',enddeep,
'material',material,
'diameter',diameter,
'roadname',roadname,
'slope',slope,
'start_elev',start_elev,
'end_elevat',end_elevat,
'start_desi',start_desi,
'end_design',end_design,
'start_natu',start_natu,
'end_nature',end_nature,
'well_chamber',well_chamber,
'well_chamber2',well_chamber2,
'well_neck',well_neck,
'sb','sb'
        )
    ) AS feature
FROM line;

查询的结果放在{ "type": "FeatureCollection", "features": [ {。。。。。。。]}中，然后字符串, "sb" : "sb"}}替换}}, 最后以后去掉，大体模糊地图上范围，大地2000 坐标 4490 中央子午线119度 15分。乱七八糟。要什么7点法。头疼。瞎几把转4326 。 减0.75，给个大体范围