CODEWITHSUNDEEP
djangogeodjango
David Foie Gras
David Foie Gras

Reputation: 2080

How can i use decimal field in geodjango?

According to https://docs.djangoproject.com/en/dev/ref/contrib/gis/tutorial/#defining-a-geographic-model, lat and lon information is stored at floatfield in geodjango.

  1. I want to know if lat and lon were stored on floatfield, what's the number of significant digits used to represent coordinate?

  2. Is there any way of changing the number of digit on floatfield in geodjango?

  3. Can i use decimalfield in geodjango instead of floatfield? So how can i do that?

Because i'm building a service that require much distance calculation depend on coordinate, i need to reduce the hugeness of calculation.

Thanks for reading my poor english writing.

Upvotes: 1

Views: 345

Answers (1)

e4c5
e4c5

Reputation: 53774

According to https://docs.djangoproject.com/en/dev/ref/contrib/gis/tutorial/#defining-a-geographic-model, lat and lon information is stored at floatfield in geodjango.

Incorrect reference and inference all together. What you are looking at is a tutorial that shows how to import the World Borders Shapefile into django. Here lat and long are really irrelevant fields. What matters is mpoly. That's probably why lat and lng are stored as floats here. But they could have avoided confusion by not using lat,lng as separate fields.

The real geodjango way of storing points is using the PointField it allows you to store additional information about the location such as SRID. Exact internal representation varies from RDBMS to RDMBS.

If you need distance calculations the only way is to use a GeometryField or one of it's sub classes (of with PointField is one) so sub topics 1,2,3 in your question aren't really relevant.

Upvotes: 1

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