gatilegrid

gatilegrid

Geoadmin custom tile grid for web mapping applications

gatilegrid is compatible with python 2.7, 3.5, 3.6 and 3.7

Installation

$ pip install gatilegrid

Usage

Several tile grids are supported, namely 21781, 2056, 3857 and 4326. Here is an exemple using 21781. For 4326, an additional parameter is available (tmsCompatible=True).

from gatilegrid import getTileGrid
from gatilegrid import GeoadminTileGridLV03 as GeoadminTileGrid

zoom = 18
tileCol = 6
tileRow = 7

# Get and initialize the grid (top-left and bottom-left are availble)
gagrid = getTileGrid(21781)(originCorner='top-left')
# With extent constraint
offset = 100000
gagridExtent = GeoadminTileGrid(extent=[gagrid.MINX + offset, gagrid.MINY + offset,
                                        gagrid.MAXX - offset, gagrid.MAXY - offset])

bounds = [xmin, ymin, xmax, ymax] = gagrid.tileBounds(zoom, tileCol, tileRow)
print(bounds)
>>> [496800.0, 247600.0, 509600.0, 260400.0]
print(gagrid.tileAddressTemplate)
>>> {zoom}/{tileCol}/{tileRow}

topLeftCorner = [xmin, ymax]
tileAddress = [tileCol, tileRow] = gagrid.tileAddress(zoom, topLeftCorner)
print(tileAddress)
>>> [6, 7]

# Get the parent tiles
parentZoom = 1
gagrid.getParentTiles(zoom, tileCol, tileRow, parentZoom)
>>> [[1, 0, 0]]

# It also works if the point is within the tile
pointInTile = [topLeftCorner[0] + 200.0, topLeftCorner[1] - 200.0]
print(gagrid.tileAddress(zoom, pointInTile))
>>> [7, 6]

# Resolution in meters
print(gagrid.getResolution(zoom))
>>> 50.0

# Scale dpi dependent (defaults to 96)
print(gagrid.getScale(zoom, dpi=96.0))
>>> 188976.0

# Tile size in meters
print(gagrid.tileSize(zoom))
>>> 12800.0

# Number of tiles at zoom
print(gagrid.numberOfTilesAtZoom(zoom))
>>> 950
# Extent dependent
print(gagridExtent.numberOfTilesAtZoom(zoom))
>>> 253

# Get the closest zoom for a given resolution
print(gagrid.getClosestZoom(245))
>>> 16

# Get the ceiling zoom for a given resolution
print(gagrid.getCeilingZoom(245))
>>> 17

# Generate tilesSpec
minZoom = 16
maxZoom = zoom
tilesSpecGenerator = gagrid.iterGrid(minZoom, maxZoom)
for i, t in enumerate(tilesSpecGenerator):
    (tileBounds, zoom, tileCol, tileRow) = t
    print(t)
    if i == 1:
        break
>>> ([420000.0, 286000.0, 484000.0, 350000.0], 16, 0, 0)
>>> ([484000.0, 286000.0, 548000.0, 350000.0], 16, 1, 0)
# Extent dependent
tilesSpecGeneratorExtent = gagridExtent.iterGrid(minZoom, maxZoom)
for i, t in enumerate(tilesSpecGeneratorExtent):
    (tileBounds, zoom, tileCol, tileRow) = t
    print(t)
    if i = 1:
        break
>>> ([484000.0, 222000.0, 548000.0, 286000.0], 16, 1, 1)
>>> ([548000.0, 222000.0, 612000.0, 286000.0], 16, 2, 1)

This module also provides a simple grid API for grid cells addressing.

from gatilegrid import Grid

extent = [485349.96, 75250.055, 833849.959, 295950.054]
resolutionX = 100.0
resolutionY = -100.0
grid = Grid(extent, resolutionX, resolutionY)

# We use singed resolution to define the origin.
# Here the origin is at the top-left corner.
print(grid.origin)
>>> [485349.96, 295950.054]

# The Grid class defines a series of useful properties
print(grid.cellArea)
>>> 10000.0
print(grid.nbCellsX)
>>> 3485
print(grid.nbCellsY)
>>> 2207
print(grid.isTopLeft)
>>> True
print(grid.isBottomRight)
>>> False

[col, row] = grid.cellAddressFromPointCoordinate([500000, 100000])
print(col)
>>> 146
print(row)
>>> 1959

# Get the extent of the cell using its address
cellExtent = grid.cellExtent(col, row)
print(cellExtent)
>>> [499949.96, 99950.054, 500049.96, 100050.054]

# Get an address range using an extent
[minCol, minRow, maxCol, maxRow] = grid.getExtentAddress([500000, 100000, 550000, 150000])
print(minCol)
>>> 146
print(minRow)
>>> 1459
print(maxCol)
>>> 646
print(maxRow)
>>> 1959

Tests

source .venv/bin/activate
python setup.py test

Publish a new version of the module

Edit $HOME/.pypirc and add (username and password in keepass):

[distutils]
index-servers =
  pypi
  pypitest

[pypi]
repository=https://upload.pypi.org/legacy/
username=iwi***
password=

[pypitest]
repository=https://test.pypi.org/legacy/
username=iwi***
password=

Bump version in setup.py.

Build, check and upload the new module to the test repository:

pip install --upgrade twine wheel setuptools
python setup.py sdist bdist_wheel
twine upload --repository testpypi dist/*

Test local install from test repository.

pip install -i https://test.pypi.org/simple/ gatilegrid

If everything is ok, push the new version to the default repository.

twine upload --repository pypi dist/*

Test the newly created module.

Create a RELEASE in github.

CONTRIBUTORS:

• Loic Gasser
• Marc Monnerat
• Nadine Piveteau
• Marcel Clausen
• Gilbert Jeinziner