csv到光栅python

Question

3 column csv (Lon, Lat, Ref) (63000 rows) and I would like to convert the "Ref" to raster. points (x,y) are being plotted. I want to plot the "Ref" column and add contour and color-fill it. Thanks

Data:

Lon,Lat, Ref
-115.0377,51.9147,0
-115.0679,51.9237,0
-115.0528,51.9237,0
-115.0377,51.9237,0
-115.1134,51.9416,0
-115.0982,51.9416,0
-115.0831,51.9416,0
-115.1437,51.9596,6
-115.1285,51.9596,6
-115.1588,51.9686,6
-115.1437,51.9686,10.5
-115.1285,51.9686,10.5
-115.1134,51.9686,8
-115.1891,51.9776,7.5
-115.174,51.9776,7.5
-115.1588,51.9776,7.5
-115.1437,51.9776,8
-115.1285,51.9776,8
-115.1134,51.9776,8
-115.1891,51.9866,7
-115.174,51.9866,7
-115.1588,51.9866,7
-115.1437,51.9866,0
-115.1285,51.9866,0
-115.1134,51.9866,0
-115.1891,51.9956,7
-113.1143,52.2385,3.5
-113.0992,52.2475,3.5
-113.084,52.2475,3.5
-113.0689,52.2475,5.5
-113.0537,52.2475,5.5

Code:

import pandas as pd
import geopandas
from shapely.geometry import Point
import fiona
import matplotlib.pyplot as plt

df=pd.read_csv('name.csv')
df1=df.interpolate()

geometry=[Point(xyz) for xyz in zip(df1.ix[:,0], df1.ix[:,1], df1.ix[:,2])]

df3=geopandas.GeoDataFrame(df1, geometry=geometry)

df3.plot()

plt.savefig('raster.tiff')

wanted result:

Answer 1

If you want to plot points from GeoPandas based on the "Ref" column, you don't need it as az coordinate.

import pandas as pd
import geopandas
from shapely.geometry import Point
import matplotlib.pyplot as plt

df = pd.read_csv('name.csv')

geometry = [Point(xy) for xy in zip(df.iloc[:, 0], df.iloc[:, 1])]

gdf = geopandas.GeoDataFrame(df, geometry=geometry)

gdf.plot(column=' Ref')

plt.savefig('raster.tiff')

You don't even need interpolate() . However, if you want to convert your vector point dataset to raster geoTIFF, plot() is not the right way to do it. I would go for gdal.Grid() as explained here. - [Python - gdal.Grid() correct use][1]

EDIT Using gdal.Grid() like this I am able to generate tif based on the sample of data you provided.

import os
import gdal

dir_with_csvs = r"/home/panda"
os.chdir(dir_with_csvs)

def find_csv_filenames(path_to_dir, suffix=".csv"):
    filenames = os.listdir(path_to_dir)
    return [ filename for filename in filenames if filename.endswith(suffix) ]
csvfiles = find_csv_filenames(dir_with_csvs)
for fn in csvfiles:
    vrt_fn = fn.replace(".csv", ".vrt")
    lyr_name = fn.replace('.csv', '')
    out_tif = fn.replace('.csv', '.tiff')
    with open(vrt_fn, 'w') as fn_vrt:
        fn_vrt.write('<OGRVRTDataSource>\n')
        fn_vrt.write('\t<OGRVRTLayer name="%s">\n' % lyr_name)
        fn_vrt.write('\t\t<SrcDataSource>%s</SrcDataSource>\n' % fn)
        fn_vrt.write('\t\t<GeometryType>wkbPoint</GeometryType>\n')
        fn_vrt.write('\t\t<GeometryField encoding="PointFromColumns" x="Lon" y="Lat" z="Ref"/>\n')
        fn_vrt.write('\t</OGRVRTLayer>\n')
        fn_vrt.write('</OGRVRTDataSource>\n')

output = gdal.Grid('outcome.tif','name.vrt')
# below using your settings - I don't have sample large enough to properly test it, but it is generating file as well  
output2 = gdal.Grid('outcome2.tif','name.vrt', algorithm='invdist:power=2.0:smoothing=1.0')  

Do you have any particular reason to use gdal via shell? [1]: https://gis.stackexchange.com/questions/254330/python-gdal-grid-correct-use

Answer 2

@ctvtkar, I am attaching a code here using gdal. When I run it, the file.vrt gets created, but not the .tif file. The erroe i get is: gdal_grid: not found. gdal is instaled

Code:

import subprocess
import os

dir_with_csvs = r"/home/panda"
os.chdir(dir_with_csvs)

def find_csv_filenames(path_to_dir, suffix=".csv"):
    filenames = os.listdir(path_to_dir)
    return [ filename for filename in filenames if filename.endswith(suffix) ]
csvfiles = find_csv_filenames(dir_with_csvs)
for fn in csvfiles:
    vrt_fn = fn.replace(".csv", ".vrt")
    lyr_name = fn.replace('.csv', '')
    out_tif = fn.replace('.csv', '.tiff')
    with open(vrt_fn, 'w') as fn_vrt:
        fn_vrt.write('<OGRVRTDataSource>\n')
        fn_vrt.write('\t<OGRVRTLayer name="%s">\n' % lyr_name)
        fn_vrt.write('\t\t<SrcDataSource>%s</SrcDataSource>\n' % fn)
        fn_vrt.write('\t\t<GeometryType>wkbPoint</GeometryType>\n')
        fn_vrt.write('\t\t<GeometryField encoding="PointFromColumns" x="Lon" y="Lat" z="Ref"/>\n')
        fn_vrt.write('\t</OGRVRTLayer>\n')
        fn_vrt.write('</OGRVRTDataSource>\n')

    gdal_cmd = 'gdal_grid -a invdist:power=2.0:smoothing=1.0 -zfield "Ref" -of GTiff -ot Float64 -l %s %s %s' % (lyr_name, vrt_fn, out_tif)

    subprocess.call(gdal_cmd, shell=True)