CODEWITHSUNDEEP
djangogeodjango
user2552806
user2552806

Reputation:

Django django.contrib.gis.db MultiPolygonField extract points

  1. I didnt find any documentation about geo dgango that contains details about the fields. Only this https://docs.djangoproject.com/en/1.9/ref/contrib/gis/model-api/#django.contrib.gis.db.models.MultiPolygonField but as you can see it is not telling us what is inside the fields and how to get it... Where can I find a deep view on the fields of geodjango such as MultiPolygonField ?

  2. Im trying to extract all the points that are in MultiPolygonField. I tried:

    mpoly = models.MultiPolygonField(srid=4326, null=False, blank=False)

def get_tooltip_title(self):
    result = "Polygon: [["
    for poly in self.mpoly.choices:
        for point in poly.coordinates:
            result += "("
            result += str(point.x)
            result += ","
            result += str(point.y)
            result += "),"
        result += "],"

    result += "]"
    return result

    But there is no "choises" in the field and I didnt found any good documentation about the field. So how can I get the points of a MultiPolygonField?

Upvotes: 0

Views: 1022

Answers (2)

e4c5
e4c5

Reputation: 53734

Though geodjango MultiPolygon isn't very well documented, mysql multipolygon is

A MultiPolygon is a MultiSurface object composed of Polygon elements.

MultiPolygon Examples

On a region map, a MultiPolygon could represent a system of lakes.

The postgis MultiPolygon is also very well documented with a few visual examples.

Basically a MultiPolygon is a collection of elements that may touch but not intersect.

Upvotes: 0

user2552806
user2552806

Reputation:

Ok, this is so stupid. There is no good documentation?!

I found the solution in someones post from 2009 http://www.paolocorti.net/2009/04/01/a-day-with-geodjango/ . It is like:

class LocationPolygon(models.Model):
    mpoly = models.MultiPolygonField(srid=4326, null=False, blank=False)
    objects = models.GeoManager()

    def get_tooltip_title(self):
        return str(self.mpoly.coords)

Upvotes: 1

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