我正在尝试在叶片地图上放置许多标记。坐标是从SQLite3表中绘制的,但是现在没有地图显示,也没有抛出错误。
def maps():
melbourne = (-37.840935, 144.946457)
map = folium.Map(location = melbourne)
try:
sqliteConnection = sqlite3.connect('25july_database.db')
cursor = sqliteConnection.cursor()
print("Connected to SQLite")
sqlite_select_query = """SELECT latitude, longitude FROM test555;"""
cursor.execute(sqlite_select_query)
items = cursor.fetchall()
for item in items:
folium.Marker(location = item)
cursor.close()
except sqlite3.Error as error:
print("Failed to read data from sqlite table", error)
finally:
if (sqliteConnection):
sqliteConnection.close()
print("The SQLite connection is closed")
我尝试将“商品”列为列表folium.Marker(location = [item])
,但抛出以下错误ValueError: Expected two (lat, lon) values for location, instead got: [(-37.7650309, 144.9613659)].
这向我表明该变量没有错,但其他地方出现了问题。
谢谢!
答案 0 :(得分:1)
要从列表中提取元组(-37.7650309, 144.9613659)
,您只需要获取第一个元素:folium.Marker(location = item[0])
您还需要将标记添加到地图:folium.Marker(location = item[0]).add_to(map)
要绘制地图,您需要在函数末尾将其返回。
您将拥有类似的内容(在我的Jupyter Notebook中有效):
def maps():
melbourne = (-37.840935, 144.946457)
map = folium.Map(location = melbourne)
try:
sqliteConnection = sqlite3.connect('25july_database.db')
cursor = sqliteConnection.cursor()
print("Connected to SQLite")
sqlite_select_query = """SELECT latitude, longitude FROM test555;"""
cursor.execute(sqlite_select_query)
items = cursor.fetchall()
for item in items:
folium.Marker(location = item[0]).add_to(map)
cursor.close()
except sqlite3.Error as error:
print("Failed to read data from sqlite table", error)
finally:
if (sqliteConnection):
sqliteConnection.close()
print("The SQLite connection is closed")
return map
N.B:
您不应使用map
作为变量的名称,因为它会遮盖Python标准库的map()
函数。