Solution: django NotSupportedError(\'Perimeter cannot use a non-projected field.\')

Cause of error

"NotSupportedError("Perimeter cannot use a non-projected field.")" This error is usually caused by you trying to Django Occurs when using an unprojected field to calculate the perimeter. There are two types of fields in

DjanGo: projected fields and unprojected fields. Projected fields are fields that represent geographic information in a plane coordinate system, while unprojected fields are fields that represent geographic information in an ellipsoid coordinate system.

If you see the "NotSupportedError("Perimeter cannot use a non-projected field.")" error, it may be because you are trying to use a non-projected field to calculate the perimeter. For example, you might see this error if you use an unprojected field to calculate the perimeter of a geographic figure.

To fix this, you need to make sure you use the projected field to calculate the perimeter. For example, if you want to calculate the circumference of a circle, you can use the following code:

from django.contrib.GIS.measure import D

# Assume that "circle" is a projected field of type Circle
perimeter = circle.perimeter

Hope this example is helpful to you.

How to solve

To solve the "NotSupportedError("Perimeter cannot use a non-projected field.")" error, you need to ensure that a projected field is used to calculate the perimeter.

The projection field is a field that represents geographic information in a plane coordinate system and can be used to calculate perimeter. For example, if you want to calculate the circumference of a circle, you can use the following code:

from django.contrib.GIS.measure import D

# Assume that "circle" is a projected field of type Circle
perimeter = circle.perimeter

If you are using unprojected fields to calculate perimeter, you will need to convert these fields to projected fields. For example, if you want to convert an unprojected field to a projected field, you can use the following code:

from django.contrib.gis.measure import D

# Assume that "circle" is a non-projected field of type Circle
perimeter = circle.transfORM(4326, clone=True).perimeter

Hope this information is helpful to you.

Usage Example

Yes, here is an example:

Suppose you have a Django model containing a circular field like this:

from django.db import models
from django.contrib.gis.db import models as gis_models

class MyModel(models.Model):
circle = gis_models.CircleField()

You can then use the following code to create a new MyModel object and assign the circumference of the circle to the circle field:

from django.contrib.gis.geos import Point
from django.contrib.gis.measure import D

# Create a point
point = Point(x=1.0, y=2.0)

# Create a circle with radius of 10 meters
circle = point.buffer(D(m=10))

# Create a new MyModel object and set the circle field
my_model = MyModel(circle=circle)
my_model.save()

Note that the above code uses the Point class to create the center of the circle and the buffer() method to create a circle. The D class is also used to specify the radius of a circle.

Hope this example is helpful to you.

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