我目前正在尝试以geoTiff格式获取Tropomi数据。我以netCDF4格式下载了一些数据。这样,我获得了三个numpy数组。一种具有纬度坐标,一种具有经度坐标,另一种具有一氧化碳值。

因此,我有一个矩阵,其中包含我的栅格值,每个值我都知道该值的经度和纬度。

有了这些信息,我如何构造地理参考栅格?

我读数据如下
    导入netCDF4
    从netCDF4导入数据集
    将numpy导入为np

file = '/home/daniel/Downloads/S5P_NRTI_L2__CO_____20190430T171319_20190430T171819_08006_01_010301_20190430T175151.nc'

rootgrp = Dataset(file, "r",format="NETCDF4")

lat = rootgrp.groups['PRODUCT']['latitude'][:]
lon = rootgrp.groups['PRODUCT']['longitude'][:]
carbon = rootgrp.groups['PRODUCT']['carbonmonoxide_total_column'][:]


获得3个形状为(1,290,215)的矩阵

现在,我想将其转换为墨卡托投影的geoTIFF,但是我不知道该怎么做。

最佳答案

gdal_translate选项似乎有效。但是这是我做的另一种明确的方式。

#importing packages
import numpy as np
from scipy import interpolate
from netCDF4 import Dataset
from shapely.geometry import Point
import geopandas as gpd
from geopy.distance import geodesic
import rasterio
import matplotlib.pyplot as plt

#load data
file = '/home/daniel/Ellipsis/db/downloaded/rawtropomi/S5P_NRTI_L2__CO_____20190430T171319_20190430T171819_08006_01_010301_20190430T175151.nc'
rootgrp = Dataset(file, "r",format="NETCDF4")
lat = rootgrp.groups['PRODUCT']['latitude'][:]
lon = rootgrp.groups['PRODUCT']['longitude'][:]
carbon = rootgrp.groups['PRODUCT']['carbonmonoxide_total_column'][:]
carbon = carbon.filled(0)
lat = lat.filled(-1000)
lon = lon.filled(-1000)

carbon = carbon.flatten()
lat = lat.flatten()
lon = lon.flatten()

#calculate the real distance between corners and get the widht and height in pixels assuming you want a pixel resolution of at least 7 by 7 kilometers
w = max(geodesic((min(lat),max(lon)), (min(lat),min(lon))).meters/7000 , geodesic((max(lat),max(lon)), (max(lat),min(lon))).meters/14000)
h = geodesic((min(lat),max(lon)), (max(lat),max(lon))).meters/14000

# create a geopandas with as its rows the latitude, longitude an the measrument values. transfrom it to the webmercator projection (or projection of your choosing)
points = [Point(xy) for xy in zip(lon, lat)]
crs = {'init': 'epsg:4326'}
data = gpd.GeoDataFrame({'value':carbon}, crs=crs, geometry=points)
data = data.to_crs({'init': 'epsg:3395'})
data['lon'] = data.bounds['maxx'].values
data['lat'] = data.bounds['maxy'].values

#make grid of coordinates. You nee de calculate the coordinate of each pixel in the desired raster
minlon = min(data['lon'])
maxlon = max(data['lon'])
minlat = min(data['lat'])
maxlat = max(data['lat'])

lon_list = np.arange(minlon, maxlon, (maxlon-minlon)/w )
lat_list = np.arange(minlat, maxlat, (maxlat-minlat)/h)

lon_2d, lat_2d = np.meshgrid(lon_list, lat_list)



#use the values in the geopandas dataframe to interpolate values int the coordinate raster
r = interpolate.griddata(points = (data['lon'].values,data['lat'].values), values = data['value'].values, xi = (lon_2d, lat_2d))
r = np.flip(r, axis = 0)

#check result
plt.imshow(r)


#save raster
transform = rasterio.transform.from_bounds(south = minlat, east = maxlon, north =     maxlat, west = minlon, width = r.shape[1], height = r.shape[2]   )
file_out = 'test.tiff'
new_dataset = rasterio.open(file_out , 'w', driver='Gtiff', compress='lzw',
                                    height = r.shape[1], width = r.shape[2],
                                    count= r.shape[0], dtype=str( r.dtype),
                                    crs=   data.crs,
                                    transform= transform)
new_dataset.write(r)
new_dataset.close()

关于python - 如何将netCDF4文件转换为geoTiff,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/55934896/

10-12 17:00