Shapefile -> Reprojected shp -> GeoJson -> Leaflet


Here’s a not-too-pretty proof of concept script that hastily glues together several blog posts, as noted in the code.

The script takes the following steps:

  1. Takes the path to a .shp file
  2. Reprojects the .shp file to 4326 (without checking if it’s already in 4326–DOH!) (via Python GDAL/OGR Cookbook)
  3. Converts the .shp to GEOJSON (by Shapefile to GeoJSON)
  4. Creates a Leaflet page using Folium (using Folium)
  5. Does all this using way too many libraries:)

from __future__ import print_function import os, sys import json from osgeo import ogr, osr import shapefile import folium def msg(s): print (s) def dashes(): msg(40*'-') def msgt(s): dashes(); msg(s); dashes() def msgx(s): dashes(); msg('ERROR'); msg(s); dashes(); sys.exit(0) def get_output_fname(fname, new_suffix): fparts = fname.split('.') if len(fparts[-1]) == 3: return '.'.join(fparts[:-1]) + new_suffix + '.' + fparts[-1] return fname + new_suffix def reproject_to_4326(shape_fname): """Re-project the shapefile to a 4326. From the Python GDAL/OGR Cookbook Source: :param shape_fname: full file path to a shapefile (.shp) :returns: full file path to a shapefile reprojected as 4326 """ if not os.path.isfile(shape_fname): msgx('File not found: %s' % shape_fname) driver = ogr.GetDriverByName('ESRI Shapefile') inDataSet = driver.Open(shape_fname) # input SpatialReference inLayer = inDataSet.GetLayer() inSpatialRef = inLayer.GetSpatialRef() # output SpatialReference outSpatialRef = osr.SpatialReference() outSpatialRef.ImportFromEPSG(4326) # create the CoordinateTransformation coordTrans = osr.CoordinateTransformation(inSpatialRef, outSpatialRef) # create the output layer outputShapefile = get_output_fname(shape_fname, '_4326') #msg('output file: %s' % outputShapefile) if os.path.exists(outputShapefile): driver.DeleteDataSource(outputShapefile) outDataSet = driver.CreateDataSource(outputShapefile) outLayer = outDataSet.CreateLayer("basemap_4326", geom_type=ogr.wkbMultiPolygon) # add fields inLayerDefn = inLayer.GetLayerDefn() for i in range(0, inLayerDefn.GetFieldCount()): fieldDefn = inLayerDefn.GetFieldDefn(i) outLayer.CreateField(fieldDefn) # get the output layer's feature definition outLayerDefn = outLayer.GetLayerDefn() # loop through the input features inFeature = inLayer.GetNextFeature() while inFeature: # get the input geometry geom = inFeature.GetGeometryRef() # reproject the geometry geom.Transform(coordTrans) # create a new feature outFeature = ogr.Feature(outLayerDefn) # set the geometry and attribute outFeature.SetGeometry(geom) for i in range(0, outLayerDefn.GetFieldCount()): outFeature.SetField(outLayerDefn.GetFieldDefn(i).GetNameRef(), inFeature.GetField(i)) # add the feature to the shapefile outLayer.CreateFeature(outFeature) # destroy the features and get the next input feature outFeature.Destroy() inFeature.Destroy() inFeature = inLayer.GetNextFeature() # close the shapefiles inDataSet.Destroy() outDataSet.Destroy() msg('output file: %s' % outputShapefile) return outputShapefile def convert_shp_to_geojson(shape_fname): """Using the pyshp library,, convert the shapefile to JSON Code is from this example: :param shape_fname: full file path to a shapefile (.shp) :returns: full file path to a GEOJSON representation of the shapefile (recheck/redo using gdal) """ if not os.path.isfile(shape_fname): msgx('File not found: %s' % shape_fname) # Read the shapefile try: reader = shapefile.Reader(shape_fname) except: msgx('Failed to read shapefile: %s' % shape_fname) fields = reader.fields[1:] field_names = [field[0] for field in fields] output_buffer = [] for sr in reader.shapeRecords(): atr = dict(zip(field_names, sr.record)) geom = sr.shape.__geo_interface__ output_buffer.append(dict(type="Feature", geometry=geom, properties=atr)) # write the GeoJSON file out_fname = os.path.join('page-out', os.path.basename(shape_fname).replace('.shp', '.json')) geojson = open(out_fname, "w") geojson.write(json.dumps({"type": "FeatureCollection","features": output_buffer}, indent=2) + "n") geojson.close() msg('file written: %s' % out_fname) return out_fname def make_leaflet_page(geojson_file, ouput_html_fname): """Using folium, make an HTML page using GEOJSON input examples: :param geojson_file: full file path to a GEO JSON file :param ouput_html_fname: name of HTML file to create (will only use the basename) """ if not os.path.isfile(geojson_file): msgx('File not found: %s' % geojson_file) # Boston mboston = folium.Map(location=[ 42.3267154, -71.1512353]) mboston.geo_json(geojson_file) #mboston.geo_json('income.json') ouput_html_fname = os.path.basename(ouput_html_fname) mboston.create_map(path=ouput_html_fname) print ('file written', ouput_html_fname) if __name__=='__main__': reprojected_fname = reproject_to_4326('data/social_disorder_in_boston/social_disorder_in_boston_yqh.shp') geojson_fname = convert_shp_to_geojson(reprojected_fname) make_leaflet_page(geojson_fname, 'disorder.html')

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Notes while working in a large academic organization.

One thought on “Shapefile -> Reprojected shp -> GeoJson -> Leaflet”

  1. My project is based on GIS in which i have two main tasks:
    1. Import shapefile- I have to import shapefile (shapefile to geojson).
    2. Export shapefile- After performing operations/editing (draw any thing on that shapefile ) i want to create duplicate shapefile as i clicked on export button. (That newly layer/shapefile will be the copy of imported shapefile).
    Now i am unable to export shapefile and it’s supportive file: shp, shx, prj, dbf.
    help me

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