README.md

Get IGN legends for WMS Raster, WMS Vecteur and WMTS webservices

Context

There is a CSV of available IGN webservices at https://geoservices.ign.fr/documentation/services/tableau_ressources

Most webservices for raster do not return the legend and point to a broken http://api.ign.fr/legendes/ as shown below

Results

From the French geoportal, we guessed the pattern to retrieve image legends and generate an "augmented" default file with the legend image URL link

To get end result look at:

• CSV file ressources_de_services_web_with_legend.csv
• JSON file ressources_de_services_web_with_legend.json

You can also get each legend image as we retrieved them locally in the repository. There are in the zip file

Not all webservices do have a legend, 241 have a legend (present.txt) and 357 do not have (no_present.txt). We didn't analysed the cause for the missing legend e.g hosted somewhere or not useful like for imagery

How it was done

Done on linux using bash.

Look at file get_legends_ign.sh for the recipe

get_legends_ign.sh

# "https://api.ign.fr/legendes" broken since a while
# mkdir legendes
# cd legendes

url=$(curl -k https://geoservices.ign.fr/documentation/services/tableau_ressources | grep -Eo "(http|https)://[a-zA-Z0-9./?=_%:-]*" | grep '.csv$')
filename="${url##*/}"
output_file_basename=ressources_de_services_web_with_legend
rm $filename
wget --no-check-certificate $url

iconv -f 'WINDOWS-1252' -t 'UTF-8' $filename > temp.txt
dos2unix temp.txt
mv temp.txt $filename
sed -e "1d" $filename > temp.txt
mv temp.txt $filename
echo -e "service;nom_cle;nom_commercial;nom_tech;url_acces\n$(cat $filename)" >| $filename

# true >| content.txt
IFS=$'\n'
for name in $(csvcut -d ";" -c 4 $filename);
  do png_url="https://www.geoportail.gouv.fr/depot/layers/${name}/legendes/${name}-legend.png"
  if curl --output /dev/null --silent --head --fail "$png_url"; then
    echo "1;$png_url" >> content.txt
  else
    echo "0;" >> content.txt
  fi;
done;
unset IFS

sed -e "1d" content.txt > temp.txt
mv temp.txt content.txt
echo -e "present;url_legend\n$(cat content.txt)" >| content.txt


paste -d ';' $filename content.txt >| "${output_file_basename}.csv"
rm content.txt $filename

grep 'WMS Vecteur\|WMS Raster\|WMTS' ""${output_file_basename}.csv"" | grep -v '0;$' >| present.txt
wc -l present.txt
# 241 avec une légende

grep 'WMS Vecteur\|WMS Raster\|WMTS' "${output_file_basename}.csv" | grep '0;$' >| no_present.txt
wc -l no_present.txt
# 357 sans une légende
# L'absence de légende peut se justifier selon les cas de figure.
# Il peut ne pas avoir ce besoin: exemple d'une orthophoto ou d'un contour simple avec une couche d'information

# Retrieve files
remote_urls=$(csvcut -d ';' -c 7 present.txt | sort | uniq)

for f in $remote_urls;
  do wget "$f";
done;

zip legends.zip *.png
rm *.png

# csvtojson --delimiter=';' "${output_file_basename}.csv" | jq  -c . | pv -b >/dev/null
csvtojson --delimiter=';' "${output_file_basename}.csv" | jq  -c . >| "${output_file_basename}.json"

legends.zip

no_present.txt

present.txt

ressources_de_services_web_with_legend.csv

ressources_de_services_web_with_legend.json