How to extract coordinates from a polygon in Python?

How to extract coordinates from a polygon in Python?

Use cv2.fillConvexPoly so that you can specify a 2D array of points and define a mask which fills in the shape that is defined by these points to be white in the mask. Some fair warning should be made where the points that are defined in your polygon are convex (hence the name fillConvexPoly ).

How to extract a polygon from an IMG?

Assuming the actual image is called img, and assuming that your x and y points denote the horizontal and vertical coordinates in the image, you can do something like this: out should all be black except for the region that is to be copied over. If you want to display this image, you can do something like:

What happens if a point is outside a polygon?

If instead, the point is outside the polygon, then any ray meets the perimeter an even number of times: This consideration is valid regardless of the relative positions of the point and the polygon.

How do you determine the inside of a polygon?

In that case, we need a procedure that allows us to determine whether a given point is inside or outside of the shape. This procedure, in turn, should work without requiring the knowledge of the analytical expression of the perimeter, but only the coordinates of the vertices.

Polygon created with: p = Polygon ( [ (0,0), (1,1), (1,0), (0,0)]) returns: If you really want the shapely point objects that make up the polygon, and not just tuples of coordinates, you can do that this way: You can convert a shapely Polygon to a NumPy array using NumPy.array.

How can you convert the coordinatesequence to a list of points?

You can convert the CoordinateSequence (including the repeated vertex) to a list of points thus: Similarly, the CoordinateSequence consisting of the vertices forming the first interior boundary is obtained as polygon.interiors [0].coords, and the list of those vertices (without the repeated point) is obtained as polygon.interiors [0].coords [:-1].

How to get coordinates from geometry in PostGIS?

– Geographic Information Systems Stack Exchange Getting coordinates from geometry in PostGIS? will return a hex value. How would I get decimal values, which is a human-readable coordination? In addition to ST_AsText (which returns geometry as WKT / Well Known Text), there are several additional output formats, like ST_AsGeoJSON ().

How to extract the coordinates from a SFC object?

A function that takes a sfc object and returns a sfc_POINT with the same length as the input. If NULL, function (x) sf::st_point_on_surface (sf::st_zm (x)) will be used. Note that the function may warn about the incorrectness of the result if the data is not projected, but you can ignore this except when you really care about the exact locations.

How can I get coordinates of polygon vertices?

Open the Feature Vertices To Points tool by clicking the ArcToolbox icon, and in the ArcToolbox pane, click Data Management Tools > Features > Feature Vertices To Points . Select a layer containing the polygon feature class as the input feature. Specify the name of the output feature class and location.

Where do I find feature vertices to points in ArcGIS?

Note: The Feature Vertices To Points tool requires an ArcGIS Desktop Advanced license. Open the Feature Vertices To Points tool by clicking the ArcToolbox icon, and in the ArcToolbox pane, click Data Management Tools > Features > Feature Vertices To Points . Select a layer containing the polygon feature class as the input feature.

How to get the first vertex of a polygon?

To get the first vertex, for example, use polygon.exterior.coords [0]. Note that the first and last points are the same; if you want a list consisting of the vertices without that repeated point, use polygon.exterior.coords [:-1]. You can convert the CoordinateSequence (including the repeated vertex) to a list of points thus:

How to find the length of a polygon in Python?

You can find the length of this object using len (polygon.exterior.coords) and can index the object like a list. To get the first vertex, for example, use polygon.exterior.coords. Note that the first and last points are the same; if you want a list consisting of the vertices without that repeated point, use polygon.exterior.coords [:-1].

How to get coordinates from a polygon in shapely?

The points forming the exterior boundary are arranged in a CoordinateSequence, which can be obtained as You can find the length of this object using len (polygon.exterior.coords) and can index the object like a list. To get the first vertex, for example, use polygon.exterior.coords [0].

How to extract a polygon from an image?

Take note that the image is initialized to be completely dark and that the only pixels that are to be copied over are the pixels defined by the polygon. Assuming the actual image is called img, and assuming that your x and y points denote the horizontal and vertical coordinates in the image, you can do something like this:

How to get coordinates of polygons in ArcGIS?

Ideally I would like them to be nicely tabulated in spreadsheet format. Use the Feature Vertices To Points tool within ArcToolbox or if you do not have Advanced license then you may use the Polygon to Point tool from ET GeoWizard (free tool).

How to get list of points inside a polygon?

Play with thickness to fill or not the polygon , see solution 1 for more details. Try this code. poly_coords are the coordinates of your polygon, ‘coord’ is coordinate of point you want to check if it is inside the polygon.