model.py 7.06 KB
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#  Particles are distributed at the nodes of a grid formed by equilateral
#  triangles. The distance between the particles, ie the length of the sides of
#  the triangles,is determined by the requirement that the area one particle
#  represents times the number of particles should equal the area of the polygon
#  determined by the outlet vertices. The "area" of one particle corresponds to
#  twice the area of one equilateral triangle, which equals
#  sqrt(3)/4*ParticleDistance**2.

#  A grid of equilateral triangles forms regular hexagons. The algorithm to
#  distribute particles is to determine one starting point, then move around
#  this following the sides of increasingly larger regular hexagons. The first
#  hexagon around the starting point has 6 vertices, the next has 12, the next
#  has 18, and so on.

#  The number of nodes are
#  1+6*1+6*2+6*3+...+6*n = 1+6*(1+2+3...+n) = 1+6*(n/2*(n+1))
#  where n is the number of hexagons (n is also the number of ParticleDistances
#  from  the center to a node on the outermost hexagon)
import math
import json
import random
from shapely import geometry


class Model(object):
  def __init__(self):
    return
  def __call__(self):  
    return self

  def centerPoints(self, newLatLng, centroid, points):
    centered = []
    center = [centroid.x,centroid.y]
    for point in points: 
      latlng = [point.x, point.y]
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      centered.append(self.centerPoint(newLatLng, center, latlng))    
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    return centered
    
  def centerPoint(self, newCenter, oldCenter, latlng):
    if (latlng[0] > oldCenter[0]):
      lat = abs(latlng[0] - oldCenter[0]) + newCenter[0]
    else: 
      lat = newCenter[0] - abs(latlng[0] - oldCenter[0])
    
    if (latlng[1] > oldCenter[1]):
      lng = abs(latlng[1] - oldCenter[1]) + newCenter[1]
    else: 
      lng = newCenter[1] - abs(latlng[1] - oldCenter[1])
    
    return [lat, lng]        

  def createHexagon(self, size, center, lvl):
    sizeLvl = size * lvl
    coords = []
    nodes = []
    for i in range(6):
      angle = 2 * math.pi / 6 * (i + 0.5)
      lat_i = center.x + sizeLvl * math.cos(angle)
      lng_i = center.y + sizeLvl * math.sin(angle) * 1.5
      coords.append(geometry.Point(lat_i, lng_i))

    for i, coord in enumerate(coords):
      nodes.append(coord)
      if lvl > 1:
        index = 0
        if (i + 1) < len(coords):
          index = i + 1
      
        latDiff = (coords[index].x - coord.x) / lvl
        lngDiff = (coords[index].y - coord.y) / lvl
        j = 1
        while (j < lvl):
          nodes.append(geometry.Point(coord.x + (latDiff * j), coord.y + (lngDiff * j)))
          j += 1
    if (lvl == 1):
      nodes.append(center)
    return {
        'center': center,
        'coordinates': coords,
        'nodes': nodes
    }
    


  def createOutlet(self,polygon):
    nrOfParticles = 500
    center = polygon.centroid
    
    points = []
    depth = []
    properties = {}
    properties['depth'] = depth
    pArea = (polygon.area)/3
    pDist = math.sqrt((4*pArea)/(nrOfParticles*math.sqrt(3)))
    counter = 0
    lvl = 1
    while (counter < nrOfParticles):
      hexagon = self.createHexagon(pDist, center, lvl)
      nodes = hexagon['nodes']
      j = 0
      while (j < len(nodes)):
        point = nodes[j]
        if polygon.contains(point):
          points.append(point)
          depth.append(0.0)
          counter += 1
        if (counter == nrOfParticles):
          break
        j += 1
      lvl += 1
      if (lvl > 100):
        break

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    print("Outlet particles count: "+str(counter))
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    return geometry.MultiPoint(points)

  def createFeatureCollection(self):
    featurecollection = {}
    featurecollection["type"] = "FeatureCollection"
    featurecollection["features"] = []
    return featurecollection
    
  def createFeature(self, geom, properties = {}):
    featurecollection = {}
    featurecollection["type"] = "Feature"
    featurecollection["properties"] = properties
    featurecollection["geometry"] = geometry.mapping(geom)
    return featurecollection


  def onlandPoints(self, points, strtree):
    result = list(points)
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    print("On land calculated")   
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    return result




  def displacePoints(self, points):
      
    p = 0
    xdisp = [0] * len(points)
    ydisp = [0] * len(points)
    minoverlap = [float('Inf')] * len(points)
    radius = [0] * len(points)
    for i in range(len(points)):
      radius[i] = 0.035 *  random.uniform(0.1, 1)
    while (p < len(points)):
      pn = p + 1
      while (pn < len(points)):
        dx = points[p][0] - points[pn][0]
        dy = points[p][1] - points[pn][1]
        centerdist = math.sqrt(dx*dx + dy*dy)
        overlap = radius[p] + radius[pn] - centerdist
        if overlap > 0:
          minoverlap[p]  = min(minoverlap[p], overlap)
          minoverlap[pn] = min(minoverlap[pn], overlap)
          if centerdist > 0:
            cosalfa = (points[pn][0] - points[p][0]) / centerdist
            sinalfa = (points[pn][1] - points[p][1]) / centerdist
          else:
            rand = random.uniform(0, 1)
            cosalfa = math.cos(rand * math.pi*math.pi)
            sinalfa = math.sin(rand * math.pi*math.pi)
          xdisp[p] = xdisp[p] - 0.5 * cosalfa * overlap
          ydisp[p] = ydisp[p] - 0.5 * sinalfa * overlap
          xdisp[pn] = xdisp[pn] + 0.5 * cosalfa * overlap
          ydisp[pn] = ydisp[pn] + 0.5 * sinalfa * overlap
        pn += 1

      disp = math.sqrt(xdisp[p]*xdisp[p]+ydisp[p]*ydisp[p])

      maxdisp = min(radius[p], 0.5 * minoverlap[p])
      if (disp > maxdisp):
        xdisp[p] = xdisp[p] * maxdisp / disp
        ydisp[p] = ydisp[p] * maxdisp / disp
      p += 1
    


    result = list(points)
    for i, dx in enumerate(xdisp):
      result[i][0] += dx 
    for i, dy in enumerate(ydisp):
      result[i][1] += dy 

    return result


  def createProperties(self, step, time, centroid, level, category):
    properties = {};
    properties['nStep'] = step
    properties['time'] = time
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    properties['meanLat'] = centroid.y
    properties['meanLon'] = centroid.x
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    properties['category'] = category
    properties['level'] = level
    return properties    


  def createOutput(self, multipoint, exercisefeature, strtree):

    featurecollection = self.createFeatureCollection()
    features = featurecollection['features']
    time = exercisefeature['properties']['time']
    properties = self.createProperties(1, time[0], multipoint.centroid, [0] * len(multipoint.geoms), [2] * len(multipoint.geoms))
    features.append(self.createFeature(multipoint, properties))
    mp = multipoint
    linestring = geometry.shape(exercisefeature['geometry'])
    for i, coord in enumerate(linestring.coords):
      points = self.centerPoints(coord, mp.centroid, mp.geoms)
      displacedpoints = self.displacePoints(points)
      # onlandpoints = self.onlandPoints(displacedpoints,strtree)
      mp = geometry.MultiPoint(displacedpoints)
      level = [0] * len(mp.geoms)
      category = [2] * len(mp.geoms)
      properties = self.createProperties((i+2), time[i+1], mp.centroid, level, category)
      features.append(self.createFeature(mp, properties))
    # features.append(self.createFeature(linestring))
    return featurecollection