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I'm trying to create a GeoDataFrame points grid from a numpy.mgrid. I already have created the numpy.mgrid with coordinates of future points.

>>>arr = np.mgrid[-1827342.1753285176:-1827523.6181312904:121j,5328243.703187092:5328092.54873913:152j]

>>>arr

array([[[-1827342.17532852, -1827342.17532852, -1827342.17532852, ...,
     -1827342.17532852, -1827342.17532852, -1827342.17532852],
    [-1827343.68735187, -1827343.68735187, -1827343.68735187, ...,
     -1827343.68735187, -1827343.68735187, -1827343.68735187],
    [-1827345.19937523, -1827345.19937523, -1827345.19937523, ...,
     -1827345.19937523, -1827345.19937523, -1827345.19937523],
    ...,
    [-1827520.59408458, -1827520.59408458, -1827520.59408458, ...,
     -1827520.59408458, -1827520.59408458, -1827520.59408458],
    [-1827522.10610793, -1827522.10610793, -1827522.10610793, ...,
     -1827522.10610793, -1827522.10610793, -1827522.10610793],
    [-1827523.61813129, -1827523.61813129, -1827523.61813129, ...,
     -1827523.61813129, -1827523.61813129, -1827523.61813129]],

   [[ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913],
    [ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913],
    [ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913],
    ...,
    [ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913],
    [ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913],
    [ 5328243.70318709,  5328242.70216426,  5328241.70114142, ...,
      5328094.5507848 ,  5328093.54976196,  5328092.54873913]]])

After, I tried this method:

>>>pd.DataFrame(data=arr[0:,0:],    
                index=???,          
                columns=['x','y'])

And after use x and y fields to create a POINT shapely geometry field. But I didn't find how to create an index.

So I tried to convert 2 parts oh the array in 2 lists like this:

>>>x = marr[0,0:].tolist()
>>>y = marr[1,0:].tolist()

But it doesn't really unpack the array.

Somebody have some tips?

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1 Answer 1

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The code below should help you out. Have a look at the comments to understand what it does.

import pandas as pd
import geopandas as gpd
import numpy as np
from shapely.geometry import Point

# create numpy mgrid
arr1 = np.mgrid[-1827342.1753285176:-1827523.6181312904:121j,5328243.703187092:5328092.54873913:152j]

# extract the x and y coordinates as flat arrays
arr1x = np.ravel(arr1[0])
arr1y = np.ravel(arr1[1])

# using the X and Y columns, build a dataframe, then the geodataframe
df1 = pd.DataFrame({'X':arr1x, 'Y':arr1y})
df1['coords'] = list(zip(df1['X'], df1['Y']))
df1['coords'] = df1['coords'].apply(Point)
gdf1 = gpd.GeoDataFrame(df1, geometry='coords')
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  • Before you answered, I found a solution that's look like yours. But your 2nd part to build the DF is better. For the extraction of coordinates, I found this x, y = np.mgrid[-1827342.1753285176:-1827523.6181312904:121j,5328243.703187092:5328092.54873913:152j] ; arrx = np.ravel(x) ; arry = np.ravel(y)
    – Tim C.
    Commented Jan 21, 2019 at 9:08
  • 1
    And to generate the np.mgrid with variables: x, y = np.mgrid[Xmin:Xmax:complex(cols),Ymin:Ymax:complex(rows)]where cols and rows are the number of columns and rows. complex(120) permet to recreate the value 120j. A simple concatenation of 120 and 'j' doesn't work.
    – Tim C.
    Commented Jan 22, 2019 at 13:14

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