gatilegrid

Geoadmin custom tile grid for web mapping applications.

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

Local Development

Setup

make setup

Tests

make test

Formatting and Linting

make format
make lint
#or
make format-lint

Release and Publish

New release and publish on PyPI is done automatically upon PR merge into master branch. For bug fixes and small new features, PR can be directly open on master. Then the PR title define the version bump as follow:

• PR title and/or commit message contains #major => major version is bumped
• PR title and/or commit message contains #patch or head branch name starts with bug-|hotfix-|bugfix- => patch version is bumped
• Otherwise by default the minor version is bumped