Question

我正在尝试重新创建this rasterio example：

import numpy as np
import rasterio
from rasterio.features import rasterize
from rasterio.transform import IDENTITY

rows = cols = 10

geometry = {
    'type': 'Polygon',
    'coordinates': [[(2, 2), (2, 4.25), (4.25, 4.25), (4.25, 2), (2, 2)]]
}


with rasterio.Env():
    result = rasterize([geometry], out_shape=(rows, cols))
    with rasterio.open(
            "test.tif",
            'w',
            driver='GTiff',
            width=cols,
            height=rows,
            count=1,
            dtype=np.uint8,
            nodata=0,
            transform=IDENTITY,
            crs={'init': "EPSG:4326"}) as out:
        out.write(result.astype(np.uint8), indexes=1)

我检查了rasterize（print(result)）的结果，该结果看上去正常且令人生厌，其结果是2x2像素的正方形：

[[0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 1 1 0 0 0 0 0 0]
 [0 0 1 1 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]
 [0 0 0 0 0 0 0 0 0 0]]

但是我得到的是全黑图像（nodata图像）。

Answer 1

尽管我无法确定产生黑色.tif图像的原因，但我得出结论，该过程按预期进行，并且可以使用matplolib.pyplot看到视觉效果。

必须对示例进行如下修改才能使用pyplot：

import rasterio
from matplotlib import pyplot
from rasterio.features import rasterize
from rasterio.transform import IDENTITY

rows = cols = 10

geometry = {
    'type': 'Polygon',
    'coordinates': [[(2, 2), (2, 4.25), (4.25, 4.25), (4.25, 2), (2, 2)]]
}


with rasterio.Env():
    result = rasterize([geometry], out_shape=(rows, cols))
    with rasterio.open(
            "test.tif",
            'w+', # Open the file in read/write mode
            driver='GTiff',
            width=cols,
            height=rows,
            count=1,
            dtype=rasterio.uint8,
            nodata=0,
            transform=IDENTITY,
            crs={'init': "EPSG:4326"}) as out:
        out.write(result.astype(rasterio.uint8), indexes=1)
        # Plot the image.
        pyplot.imshow(out.read(1))
        pyplot.show()

栅格化几何示例不起作用

1 个答案: