caculating angle of polygon

Hi, any one can help me for calculating the angles of polygon within ESRI shapefile

[Majid Al-Sirafi]

please help me

i want to calculate the angles of polygon feature within ESRI shapefile

[nick]

Hello Majid,

To calculate the angles of a polygon from the shapefile in MATLAB, please follow these steps:

• Use 'shaperead' function to read the shapefile and extract the polygon data.
• For each polygon, extract the vertices coordinates and compute the angles at each vertex using arctan function over the vectors obtained using current and previous index as shown :

v1 = [x(prevIdx) - x(currIdx), y(prevIdx) - y(currIdx)];
v2 = [x(nextIdx) - x(currIdx), y(nextIdx) - y(currIdx)];
        
dotProd = dot(v1, v2);
crossProd = v1(1)*v2(2) - v1(2)*v2(1); 
angles(j) = atan2(abs(crossProd), dotProd) * (180/pi)

Kindly refer to the documentation by executing the following command in MATLAB Command Window to know more about the 'shaperead' function:

doc shaperead