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update Grid alg to avoid some coordinate precision issues

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alexbruy committed Oct 3, 2014
1 parent 48fde06 commit 558765addf58815be216d6b4f54fc2f522ad6b85
Showing with 107 additions and 75 deletions.
  1. +107 −75 python/plugins/processing/algs/qgis/mmqgisx/Grid.py
@@ -104,8 +104,10 @@ def processAlgorithm(self, progress):
else:
geometryType = QGis.WKBLineString

fields = [QgsField('lon', QVariant.Double, '', 24, 16),
QgsField('lat', QVariant.Double, '', 24, 16)
fields = [QgsField('left', QVariant.Double, '', 24, 16),
QgsField('top', QVariant.Double, '', 24, 16),
QgsField('right', QVariant.Double, '', 24, 16),
QgsField('bottom', QVariant.Double, '', 24, 16)
]

writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields,
@@ -126,113 +128,143 @@ def processAlgorithm(self, progress):

del writer

def _rectangleGridLine(self, writer, width, height, originX, originY, hSpacing, vSpacing):
def _rectangleGridLine(self, writer, width, height, originX, originY,
hSpacing, vSpacing):
ft = QgsFeature()

x = originX
while x <= originX + width:
polyline = []
columns = int(floor(float(width) / hSpacing))
rows = int(floor(float(height) / vSpacing))

y = originY
while y <= originY + height:
# Longitude lines
for col in xrange(0, columns + 1):
polyline = []
x = originX + (col * hSpacing)
for row in xrange(0, rows + 1):
y = originY + (row * vSpacing)
polyline.append(QgsPoint(x, y))
y += vSpacing

ft.setGeometry(QgsGeometry.fromPolyline(polyline))
ft.setAttributes([x, 0])
ft.setAttributes([x, originY, x, originY + (rows * vSpacing)])
writer.addFeature(ft)

x += hSpacing

y = originY
while y <= originY + height:
# Latitude lines
for row in xrange(0, rows + 1):
polyline = []

x = originX
while x <= originX + width:
y = originY + (row * vSpacing)
for col in xrange(0, columns + 1):
x = originX + (col * hSpacing)
polyline.append(QgsPoint(x, y))
x += hSpacing

ft.setGeometry(QgsGeometry.fromPolyline(polyline))
ft.setAttributes([0, y])
writer.addFeature(ft)

y += hSpacing
ft.setAttributes([originX, y, originX + (col * hSpacing), y])
writer.addFeature(feature)

def _rectangleGridPoly(self, writer, width, height, originX, originY, hSpacing, vSpacing):
def _rectangleGridPoly(self, writer, width, height, originX, originY,
hSpacing, vSpacing):
ft = QgsFeature()

x = originX
while x < originX + width:
y = originY
while y < originY + height:
columns = int(floor(float(width) / hSpacing))
rows = int(floor(float(height) / vSpacing))

for col in xrange(0, columns):
# (column + 1) and (row + 1) calculation is used to maintain
# topology between adjacent shapes and avoid overlaps/holes
# due to rounding errors
x1 = originX + (col * hSpacing)
x2 = originX + ((col + 1) * hSpacing)
for row in xrange(0, rows):
y1 = originY + (row * vSpacing)
y2 = originY + ((row + 1) * vSpacing)

polyline = []
polyline.append(QgsPoint(x, y))
polyline.append(QgsPoint(x + hSpacing, y))
polyline.append(QgsPoint(x + hSpacing, y + vSpacing))
polyline.append(QgsPoint(x, y + vSpacing))
polyline.append(QgsPoint(x1, y1))
polyline.append(QgsPoint(x2, y1))
polyline.append(QgsPoint(x2, y2))
polyline.append(QgsPoint(x1, y2))
polyline.append(QgsPoint(x1, y1))

ft.setGeometry(QgsGeometry.fromPolygon([polyline]))
ft.setAttributes([x + hSpacing / 2.0, y + vSpacing / 2.0])
ft.setAttributes([x1, y1, x2, y2])
writer.addFeature(ft)
y += vSpacing

x += hSpacing

def _diamondGrid(self, writer, width, height, originX, originY, hSpacing, vSpacing):
def _diamondGrid(self, writer, width, height, originX, originY,
hSpacing, vSpacing):
ft = QgsFeature()

x = originX
colNum = 0
while x < originX + width:
if colNum % 2 == 0:
y = originY
else:
y = originY + vSpacing / 2.0
halfHSpacing = hSpacing / 2
halfVSpacing = vSpacing / 2

columns = int(floor(float(width) / halfHSpacing))
rows = int(floor(float(height) / vSpacing))

for col in xrange(0, columns):
x1 = originX + ((col + 0) * halfHSpacing)
x2 = originX + ((col + 1) * halfHSpacing)
x3 = originX + ((col + 2) * halfHSpacing)

for row in xrange(0, rows):
if (col % 2) == 0:
y1 = originY + (((row * 2) + 0) * halfVSpacing)
y2 = originY + (((row * 2) + 1) * halfVSpacing)
y3 = originY + (((row * 2) + 2) * halfVSpacing)
else:
y1 = originY + (((row * 2) + 1) * halfVSpacing)
y2 = originY + (((row * 2) + 2) * halfVSpacing)
y3 = originY + (((row * 2) + 3) * halfVSpacing)

while y < originY + height:
polyline = []
polyline.append(QgsPoint(x + hSpacing / 2.0, y))
polyline.append(QgsPoint(x + hSpacing, y + vSpacing / 2.0))
polyline.append(QgsPoint(x + hSpacing / 2.0, y + vSpacing))
polyline.append(QgsPoint(x, y + vSpacing / 2.0))
polyline.append(QgsPoint(x1, y2))
polyline.append(QgsPoint(x2, y1))
polyline.append(QgsPoint(x3, y2))
polyline.append(QgsPoint(x2, y3))
polyline.append(QgsPoint(x1, y2))

ft.setGeometry(QgsGeometry.fromPolygon([polyline]))
ft.setAttributes([x + hSpacing / 2.0, y + vSpacing / 2.0])
ft.setAttributes([x1, y1, x3, y3])
writer.addFeature(ft)
y += vSpacing

x += hSpacing / 2.0
colNum += 1

def _hexagonGrid(self, writer, width, height, originX, originY, hSpacing, vSpacing):
def _hexagonGrid(self, writer, width, height, originX, originY,
hSpacing, vSpacing):
ft = QgsFeature()

xVertexLo = 0.288675134594813 * vSpacing
xVertexHi = 0.577350269189626 * vSpacing
# To preserve symmetry, hspacing is fixed relative to vspacing
xXertexLo = 0.288675134594813 * vSpacing;
xXertexHi = 0.577350269189626 * vSpacing;
hSpacing = xVertexLo + xVertexHi
x = originX + xVertexHi

colNum = 0
while x < originX + width:
if colNum % 2 == 0:
y = originY + vSpacing / 2.0
else:
y = originY + vSpacing
halfVSpacing = vSpacing / 2

columns = int(floor(float(width) / hSpacing))
rows = int(floor(float(height) / vSpacing))

for col in xrange(0, columns):
# (column + 1) and (row + 1) calculation is used to maintain
# topology between adjacent shapes and avoid overlaps/holes
# due to rounding errors
x1 = originX + (col * hSpacing) # far left
x2 = x1 + (xVertexHi - xVertexLo) # left
x3 = originX + ((col + 1) * hSpacing) # right
x4 = x3 + (xVertexHi - xVertexLo) # far right

for row in xrange(0, rows):
if (col % 2) == 0:
y1 = originY + (((row * 2) + 0) * halfVSpacing) # hi
y2 = originY + (((row * 2) + 1) * halfVSpacing) # mid
y3 = originY + (((row * 2) + 2) * halfVSpacing) # lo
else:
y1 = originY + (((row * 2) + 1) * halfVSpacing) # hi
y2 = originY + (((row * 2) + 2) * halfVSpacing) # mid
y3 = originY + (((row * 2) + 3) * halfVSpacing) # lo

while y < originY + height:
polyline = []
polyline.append(QgsPoint(x + xVertexHi, y))
polyline.append(QgsPoint(x + xVertexLo, y + vSpacing / 2.0))
polyline.append(QgsPoint(x - xVertexLo, y + vSpacing / 2.0))
polyline.append(QgsPoint(x - xVertexHi, y))
polyline.append(QgsPoint(x - xVertexLo, y - vSpacing / 2.0))
polyline.append(QgsPoint(x + xVertexLo, y - vSpacing / 2.0))
polyline.append(QgsPoint(x1, y2))
polyline.append(QgsPoint(x2, y1))
polyline.append(QgsPoint(x3, y1))
polyline.append(QgsPoint(x4, y2))
polyline.append(QgsPoint(x3, y3))
polyline.append(QgsPoint(x2, y3))
polyline.append(QgsPoint(x1, y2))

ft.setGeometry(QgsGeometry.fromPolygon([polyline]))
ft.setAttributes([x, y])
ft.setAttributes([x1, y1, x4, y3])
writer.addFeature(ft)
y += vSpacing

x += hSpacing
colNum += 1

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