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

Question

目标：使用ArcGIS的行驶时间计算数据并使用Folium而不是ArcGIS / ESRI的映射显示结果。

说明：使用arcgis程序包，我可以获得围绕给定点的行驶时间数据，从而为我提供了要在地图上显示的边界区域。使用ArcGIS可以很好地处理来自ArcGIS的数据，地图，但是，显示速度非常慢，并且通常在ArcGIS地图上显示其他元素（例如半径，单个点以及带有自定义图标的任何元素）要花费更多的时间。但是，Folium可以很好地显示所有这些额外数据，并且加载速度比ArcGIS要快得多。

障碍：我正在寻找一种方法来使用从ArcGIS返回的数据，然后使用Folium显示它。我遇到的问题是，虽然来自ArcGIS的数据说它包括坐标数据，但它们的值太大，以至于无法达到纬度/经度。似乎有某种方法可以“解码”这些值以与Folium一起使用，或者一旦尝试与Folium一起使用时，也许我只是没有将ArcGIS中的数据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看起来很接近这个样子-尽管正如我所说，GeoJson数据现在无法插入：

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。我确实知道这个geojson可以工作：

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。因此，实际上，需要弄清楚如何从ArcGIS中“解码”这些值或将其转换为正确的数据类型。任何帮助，建议或想法都将不胜感激。

Answer 1

您必须解决两个问题。首先是将ArcGIS x，y转换为lat，lon，这可以使用以下函数完成：

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]

代替drivetime_data_geojson = target.query().to_geojson使用drivetime_data_dict = target.query().to_dict()，您会注意到，将其转换为字典时，键“坐标”将更改为“环”，这对于下一步很重要。接下来，遍历字典并针对坐标值运行上述功能，以将其更新为GPS坐标。然后，您需要将字典的格式调整为大叶可以识别的形式，并从本质上提取“环”数据，该数据现在包含您的坐标值，并且将是这样的：

default_geojson_structure = {"type": "FeatureCollection", "features": 
                           [{"type":"Feature", "geometry": {"type": "Polygon", 
                            "coordinates":drivetime_data_dict['features'][0]
                             ['geometry']['rings'][0]]}}]}

现在只需创建一个叶片特征组：

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)

在保存地图和不保存地图以及运行Webview方面，像从那里开始的其他工作一样，您将看到带有行驶时间边界的地图。