Solve NotImplementedError(\'Area on geodetic coordinate systems not supported.\') error in django

Cause of error

If "NotImplementedError" occurs when using Django, it may be because you are trying to use an unimplemented function .

Specifically, if you see the error message "Area on geodetic coordinate systems not supported.", you are having trouble trying to calculate area on a geographic coordinate system (such as WGS84). Since the geographic coordinate system is not a projected coordinate system, the area cannot be calculated directly. You need to use a projected coordinate system (such as UTM) or use a special algorithm to calculate the area on a geographic coordinate system.

If you wish to solve this problem, you can try using a projected coordinate system or use a special algorithm like Haversine's formula to calculate the area on a geographic coordinate system.

Hope this information can help you solve the problem. If you have any further questions please feel free to let me know.

How to solve

To solve the "NotImplementedError" error, you need to identify the code that caused the error and find an alternative.

Specifically, if you see the error message "Area on geodetic coordinate systems not supported.", you are having trouble trying to calculate area on a geographic coordinate system (such as WGS84). Since the geographic coordinate system is not a projected coordinate system, the area cannot be calculated directly. You can use one of the following methods to solve this problem:

Use a projected coordinate system (such as UTM): If your data uses a projected coordinate system, you can use standard geoprocessing toolsCalculate area.

Use a special algorithm: If your data uses a geographic coordinate system, you can use a special algorithm like Haversine's formula to calculate area.

Hope this information can help you solve the problem. If you have any further questions please feel free to let me know.

Usage Example

The following is an example of using the Haversine formula to calculate the area on a geographic coordinate system:

from math import sin, cos, sqrt, atan2, radians

# 计算两点之间的距离
def distance(lat1, lon1, lat2, lon2):
# 将角度转换为弧度
lat1 = radians(lat1)
lon1 = radians(lon1)
lat2 = radians(lat2)
lon2 = radians(lon2)

# 计算差值
dlon = lon2 - lon1
dlat = lat2 - lat1

# Haversine 公式
a = sin(dlat / 2)**2 + cos(lat1) * cos(lat2) * sin(dlon / 2)**2
c = 2 * atan2(sqrt(a), sqrt(1 - a))

# 地球半径
radius = 6371

return c * radius

# 计算地理坐标系上的面积
def area(coordinates):
# 将坐标转换为度
coordinates = [[coord[0] / 1000000, coord[1] / 1000000] for coord in coordinates]

# 将坐标按照顺序连接起来
coordinates.append(coordinates[0])

# 计算面积
area = 0
for i in range(len(coordinates) - 1):
area += coordinates[i][0] * coordinates[i + 1][1] - coordinates[i][1] * coordinates[i + 1][0]

return abs(area) / 2

# 示例坐标
coordinates = [[454545, 123456], [454546, 123456], [454547, 123456]]

print(area(coordinates))

Below is an explanation of the reasons and solutions for NotImplementedError("Area on geodetic coordinate systems not supported.") in djan

Go:

NotImplementedError("Area on geodetic coordinate systems not supported.") means that Django does not support calculating the area on the geographical coordinate system. In django, if you try to use the `Area` property to calculate the area on a geographic coordinate system, you will get this error.

To solve this problem, you can use a custom function to calculate the area in the geographic coordinate system. For example, you can use Haversine's formula or other methods to calculate area on a geographic coordinate system. Here is an example of using the Haversine formula to calculate area on a geographic coordinate system:

from math import sin, cos, sqrt, atan2, radians

# 计算两点之间的距离
def distance(lat1, lon1, lat2, lon2):
# 将角度转换为弧度
lat1 = radians(lat1)
lon1 = radians(lon1)
lat2 = radians(lat2)
lon2 = radians(lon2)

# 计算差值
dlon = lon2 - lon1
dlat = lat2 - lat1

# Haversine 公式
a = sin(dlat / 2)**2 + cos(lat1) * cos(lat2) * sin(dlon / 2)**2
c = 2 * atan2(sqrt(a), sqrt(1 - a))

# 地球半径
radius = 6371

return c * radius

# 计算地理坐标系上的面积
def area(coordinates):
# 将坐标转换为度
coordinates = [[coord[0] / 1000000, coord[1] / 1000000] for coord in coordinates]

# 将坐标按照顺序连接

After connecting the coordinates sequentially, you can use the function that calculates the distance between two points (the distance function above) to calculate the perimeter of the polygon, and then use the perimeter and the height of the polygon to calculate the area of ​​the polygon.

It should be noted that the area calculated by this method is not the real area, but the area on the projection plane. This can lead to large errors, so you should be aware of errors when calculating area using this method.

In addition, you can use Django's `GEOSGeometry` object or other functions to calculate the area on a geographic coordinate system. For example, you can use the `GEOSGeometry.area` function to calculate the area in a geographic coordinate system.

Hope the above information can help you solve the problem.

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