extract-table-from-geojson

#!/bin/bash

## Extract tabular data from a simple geojson:
##
## bash $ bash ./extract-table-from-geojson tst.json
## bash $ bash ./extract-table-from-geojson tst.json > tst.tsv
##
## Dt: 2022.06.27
##
## NOTE: This script cannot deal with arrays/objects in the GeoJSON!
##       Most probably will need Python/R/JavaScript to extract more complex json objects from GeoJSON.
##
## GeoJSON Feature properties reference:  https://datatracker.ietf.org/doc/html/rfc7946#section-3.2 
##

set -euo pipefail
traditionalIFS="${IFS}"
IFS=$'\n\t'

tmpdir=$(mktemp -d /tmp/tmp.VL.$(basename $0).XXXXXXXXXX)
cleanup() {
  rm -rf "${tmpdir}"
}
trap cleanup EXIT QUIT INT
## pushd ${tmpdir}

usage() {
  echo "Usage: ${0} <geojson-file-name>"
  exit 159
}

if [[ $# -ne 1 ]]; then
  usage
fi

inputjson="$1"

## 1. first extract all the keys that are in the geojson
## 2. Copy the list printed from the previous command into the following command
## 3. It's better to output the resulting tsv to a file to be analyzed by R or pandas.

## The below script does all the three steps listed above.

cols=$( jq '[.features[].properties|keys]|unique[0][]' "${inputjson}" )
cols=${cols//$'"'/}
## cols=( ${cols//$'"'/} )
## declare -p cols

header="${cols//$'\n'/$'\t'}"
cols="[ .${cols//$'\n'/, .} ]"
cols=".features[].properties|${cols} | @tsv"
## declare -p cols

## outputname="${1%%.json}-$(date +%Y%m%d).tsv" ## Make sure extension matches what we are outputting...
## jq --raw-output "${cols}" "${inputjson}" >"${outputname}"
echo "${header}"
jq --raw-output "${cols}" "${inputjson}"