Add support for conversion GPKG -> CSV

[schoeller]

Dear all,

thanks for this project.
I see a need to convert from GPKG->CSV file format starting out from #39. I have written a first script to compile from attached sample file buildings from a GPKG-package into CSV format. Thus one should be able to edit a GPKG-file through GIS and later serve as model input.

Best regards

Sebastian

"""
Sources:
Polyline geometry with attribute measuredHeight to be converted into CSV format as per documentation
csv2building_polygons(file name, floor height=3)
Module: shallow_water.data_manager
Convert CSV files of the form:
easting,northing,id,floors
422664.22,870785.46,2,0
422672.48,870780.14,2,0
422668.17,870772.62,2,0
422660.35,870777.17,2,0
422664.22,870785.46,2,0
422661.30,871215.06,3,1
422667.50,871215.70,3,1
422668.30,871204.86,3,1
422662.21,871204.33,3,1
422661.30,871215.06,3,1

https://stackoverflow.com/questions/69859170/how-acess-get-extract-the-values-of-polygon-in-a-geometry-column-of-geopandas-da
https://stackoverflow.com/questions/56709561/how-to-smartly-loop-over-all-points-in-a-geodataframe-and-look-at-nearest-neig
https://stackoverflow.com/questions/44513738/pandas-create-empty-dataframe-with-only-column-names
https://stackoverflow.com/questions/16923281/writing-a-pandas-dataframe-to-csv-file#16923367
"""

import pandas as pd
import geopandas as gpd

def coord_lister(geom):
    coords = list(geom.exterior.coords)
    return (coords)

def write_csv_files(row):
    dir_path = './'
    file_name = dir_path + '_building_' + str(row.id) + '.csv'
    coords = coord_lister(row.geometry)
    df = pd.DataFrame(columns=['easting','northing','id','floors'])
    for xy in coords:
        df.loc[len(df)] = [xy[0], xy[1], int(row.id), int(row.floors)]
    df['id'] = df['id'].astype(int)
    df['floors'] = df['floors'].astype(int)
    df.to_csv(file_name, sep=',', header=True, index=None)
    return(file_name)

if __name__ == "__main__":
    gdf = gpd.read_file("buildings_mod.gpkg")
    for index,row in gdf.iterrows():
        file_name = write_csv_files(row)
        print("Writing file " + str(file_name))
    print("Files have been written\n")

buildings_mod.zip