如何格式化 ArcGIS FeatureSet/FeatureCollection 以与 Folium 一起使用

Question

目标：使用 ArcGIS 的行驶时间计算数据，并使用 Folium 代替 ArcGIS/ESRI 的映射来显示结果。

说明：使用 arcgis 包，我能够获取给定点周围的行驶时间数据，为我提供要在地图上显示的边界区域。来自 ArcGIS 的数据，使用 ArcGIS 的地图就可以了，但是，在 ArcGIS 地图上显示其他元素（例如半径、单个点和任何带有自定义图标的东西）显示速度非常慢，而且要花费更多时间。但是，Folium 可以很好地显示所有这些额外的数据，并且加载速度比 ArcGIS 快得多。

障碍：我正在寻找一种方法来使用从 ArcGIS 返回的这些数据，然后使用 Folium 显示它。我遇到的问题是来自 ArcGIS 的数据，虽然它说它包含坐标数据，但其值太大而不能成为纬度/经度。似乎有某种方法可以“解码”这些值以与 Folium 一起使用，或者我可能只是在尝试将 ArcGIS 中的数据与 Folium 一起使用时没有将其用作正确的数据类型。

import pandas
import arcgis
import webview

data = {'address': {0:'2015 Terminal Way'}, 'city': {0:'Reno'}, 'state': {0: 'NV'}, 'zip': {0:'89502'}}
df = pandas.DataFrame(data)
# Obviously I'm unable to include my username and password - which I understand probably limits who can help with this question since without logging in, you wouldn't be able to test my code, but there's nothing I can do about it
my_gis = arcgis.gis.GIS("https://www.arcgis.com", username, password)
address_layer = my_gis.content.import_data(df, address_fields={"Address":"address","City":"city","State":"state","Zip":"zip"})
target = arcgis.features.use_proximity.create_drive_time_areas(input_layer=address_layer, break_values=[5], break_units="Minutes", overlap_policy="Overlap")
# NOTE - ArcGIS documentation states that if an output name is given, the return object is a FeatureSet, but since I leave it blank, it is a FeatureCollection - not sure if that matters either
drivetime_data_geojson = target.query().to_geojson
# The above line returns as below, though trimmed down a bit to save space - I'm so sorry it's so long but pasting it in was the only way I could think of to allow others to test it in Folium

drivetime_data_geojson = '{"type": "FeatureCollection", "features": [{"type": "Feature", "geometry":
{"type": "Polygon", "coordinates": [[[-13334722.942400001, 4801659.346199997], [-13334622.9429,
4801594.495999999], [-13334572.9431, 4801335.0988000035], [-13334572.9431, 4800232.736199997], 
[-13334197.9448, 4800232.736199997], [-13334122.9452, 4800297.577799998], [-13334022.945700001, 
4800167.895199999], [-13334047.945500001, 4800005.794399999], [-13334122.9452, 4799940.954700001], 
[-13334572.9431, 4799940.954700001], [-13334622.9429, 4799227.746699996], [-13334497.943500001, 
4799195.329400003], [-13334447.9437, 4799065.6611], [-13334222.944699999, 4799065.6611], 
[-13333947.9459, 4798968.4108000025], [-13333522.947900001, 4798676.666100003], [-13332722.9515, 
4798579.419799998], [-13332622.952, 4798449.759499997], [-13332722.9515, 4798287.686399996], 
[-13333247.9492, 4798320.100699998]]]}}]}'

# This is how it would be displayed using ArcGIS
# Creating the basemap image
map = my_gis.map(location='2015 Terminal Way Reno, NV 89502')
# Adding the layer to the map
map.add_layer(drivetime_data)
folder_path = os.getcwd()
path_to_map = folder_path + '\\arcgis_to_folium.html'
# webview is just a lightweight browser package that allows for easy viewing of these maps
webview.create_window('MAP', path_to_map)
webview.start() 

Folium 看起来与此类似 - 尽管正如我所说，GeoJson 数据现在没有引入：

import folium

folium_map = folium.Map(location=[39.505745, -119.77869])
drivetime_layer = folium.FeatureGroup(name='Drive Time')
folium.GeoJson(drivetime_data_geojson).add_to(drivetime_layer)
drivetime_layer.add_to(folium_map)
folium.LayerControl().add_to(folium_map)
folium_map.save('folium_drivetime_attempt.html')
path_to_map = folder_path + '\\folium_drivetime_attempt.html'
webview.create_window('MAP', path_to_map)
webview.start()

此地图将加载，但不会有任何图层。我知道这个 geojson 会起作用：

drivetime_data_geojson = '{"type": "FeatureCollection", "features": [{
"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [
[[-119.766227, 39.856011], [-120.260612, 39.251417], [-119.067222, 39.246099]]]}}]}'

因为它使用 GPS 坐标而不是 ArcGIS 中的这些奇怪值。所以真的，这是一个弄清楚如何从 ArcGIS 中“解码”这些值或将其转换为正确数据类型的问题。非常感谢任何帮助、建议或想法。

Answer 1

您必须处理两个问题。首先是将 ArcGIS x, y 转换为 lat, lon，这可以通过如下函数完成：

import math

def meters_to_coords(y, x):
    if y > 0:
        z = -20037508.3427892
    else:
        z = 20037508.3427892

    lon = (y / z) * 180
    lat = (x / z) * 180
    lat = 180 / math.pi * (2 * math.atan(math.exp(lat * math.pi / 180)) - math.pi / 2)
    return [lon, lat]

而不是drivetime_data_geojson = target.query().to_geojson 使用drivetime_data_dict = target.query().to_dict() 您会注意到，当您将其转换为字典时，键“坐标”更改为“环”，这对于下一步很重要。接下来，遍历 dict 并针对坐标值运行上述函数以将它们更新为 GPS 坐标。然后，您需要将字典的格式调整为 folium 可以识别的格式，并从本质上提取“环”数据，该数据现在包含您的坐标值，如下所示：

# Grab the same list of drive time values you sent into the ArcGIS request and use it here, 
# since you'll get a separate set of x,y data for each driving time you request - 
# per above, break_values was just [5]

drivetime_ranges = break_values
first_pass = False

for n in range(len(drivetime_ranges)):
    for i, each in enumerate(drivetime_data_dict['features'][n]['geometry']['rings'][0]):
        drivetime_data_dict['features'][n]['geometry']['rings'][0][i] = meters_to_coords(each[0], each[1])
    if first_pass is not True:
        default_geojson_structure = {
                                     "type": "FeatureCollection", 
                                     "features": [{"type": "Feature",
                                     "geometry": {"type": "Polygon", 
                                     "coordinates":
                                     [drivetime_data_dict['features'][n]
                                     ['geometry']['rings'][0]]}}]
                                     }
        first_pass = True
    else:
        default_geojson_structure['features'].append({"type": "Feature",
        "geometry": {"type": "Polygon", "coordinates":
        [dt_map_overlay['features'][n]['geometry']['rings'][0]]}})

print(default_geojson_structure)

现在只需创建一个 folium FeatureGroup：

dt_layer = folium.FeatureGroup(name='Drive Time')

并将default_geojson_structure 加载到以下函数中并将其添加到您的图层中。

folium.GeoJson(default_geojson_structure, style_function=lambda x: {'fillColor': 
'#0000ff'}).add_to(dt_layer)

其余的就像你从那里做的那样，在保存地图和不运行 webview 方面，你会看到你的行驶时间边界的地图。