GeoServer获取图层选点的数值

Posted 2023-02-15 xbw12138

需求

需要把遥感影像分析的结果展示在地图上，该遥感影像是通过算法反演的结果，进行了着色，需要通过经纬度获取相应的数值。Geoserver上发布的图层已经具有地图选点获取灰度值的功能，采用Openlayers实现，我们这里需要把该功能封装成api接口。下图是Geoserver的Openlayers展示界面。

代码

# -*- coding: utf-8 -*-
import warnings
from pyproj import Proj, transform
import requests
import json
from config import GeoServer

warnings.filterwarnings("ignore")


def to_bbox(lon, lat):
    c = 50
    x, y = transform(Proj(init='EPSG:4326'), Proj(init="EPSG:32650"), lon, lat)
    return ",,,".format(x - c, y - c, x + c, y + c)


def get_value(lon, lat, workspace, belong, indicator, time):
    print(lon, lat, workspace, belong, indicator, time)
    try:
        layers = ":__".format(workspace, belong, indicator, time)
        bbox = to_bbox(lon, lat)
        url = "/wms?" \\
              "SERVICE=WMS" \\
              "&VERSION=1.1.1" \\
              "&REQUEST=GetFeatureInfo" \\
              "&FORMAT=image/jpeg" \\
              "&TRANSPARENT=true" \\
              "&QUERY_LAYERS=" \\
              "&LAYERS=" \\
              "&exceptions=application/vnd.ogc.se_inimage" \\
              "&INFO_FORMAT=application/json" \\
              "&FEATURE_COUNT=50" \\
              "&X=50" \\
              "&Y=50" \\
              "&SRS=EPSG:32650" \\
              "&STYLES=" \\
              "&WIDTH=101" \\
              "&HEIGHT=101" \\
              "&BBOX=".format(GeoServer, layers, layers, bbox)
        print(url)
        response = requests.get(url, timeout=5)
        temp = json.loads(response.text)['features'][0]['properties']['GRAY_INDEX']
        if temp < -2:
            return 0
        else:
            return round(temp, 3)
    except:
        return 0


if __name__ == '__main__':
    lon = 116.17356
    lat = 34.7716
    workspace = "inversion"
    belong = "武汉"
    indicator = "疫情"
    time = "2020-02"
    print(get_value(lon, lat, workspace, belong, indicator, time))

最终实现输入相应经纬度获取图层的对应的灰度值。