i=Import["/Users/dibyenduroy/Library/Mobile Documents/com~apple~CloudDocs/Test/coastline.png"]

edge := EdgeDetect[i]

edge

ImageData[edge]

lineser = ImageLines[edge]

HighlightImage[edge,lineser]

pts =PixelValuePositions[edge, 1]

radius = 300

fpix[x_,y_] = 1

pts - {207,1183}