2020 / Day 12: no gis software

Data

• OpenStreetMap contributors

Tools

PostGIS, GeoServer, shell.

Summary

Back in July 2020 FOSS4G Europe was supposed to take place in Valmiera, Latvia. But it didn’t. Because of you know what. So I suddenly got this idea, that I need to do a map of Valmiera as shout-out to my fellow LOCers. And remembering mapscii decided to do it in the terminal with a simplistic bash script using GeoServer UTFGrid output from PostGIS database.

#!/bin/bash
fg_black="$(tput setaf 0)"
fg_red="$(tput setaf 1)"
fg_green="$(tput setaf 2)"
fg_yellow="$(tput setaf 3)"
fg_blue="$(tput setaf 4)"
fg_magenta="$(tput setaf 5)"
fg_cyan="$(tput setaf 6)"
fg_white="$(tput setaf 7)"
reset="$(tput sgr0)"

data=$(curl "http://localhost:8080/geoserver/f/wms?service=WMS&version=1.1.0&request=GetMap&layers=f:admin,f:waters,f:builtup,f:roads&WIDTH=830&HEIGHT=250&BBOX=577579.7139896681%2C6373247.321590611%2C594758.7926965223%2C6381836.860944037&srs=EPSG%3A3301&format=application%2Fjson%3Btype%3Dutfgrid" | jq -r '.grid | join("\n")')

sleep 4

for (( i=0; i<${#data}; i++ )); do
 v=${data:$i:1}
 c=${fg_white}
 if [[ ${v} == ' ' ]]
 then
   v="¤"
 fi
 case $v in
  "!") c=${fg_yellow};;
  "#") c=${fg_yellow};;
  "&") c=${fg_yellow};;
  "%") c=${fg_yellow};;
  "(") c=${fg_black};;
  "'") c=${fg_red};;
  "$") c=${fg_blue};;
  "¤") c=${fg_green};;
 esac
 sleep 0.00001 | echo -ne "${c}${v}${reset}"
done
echo ""

Note the use of sleep for inbetween pause before echoing a char back on screen. And I know I’m evil, but using epsg:3301 for Northern Latvia is ok. I guess… :D

hi-res

Shell scripting a WMS GetMap response as utfgrid from GeoServer. Data by OpenStreetMap contributors.

Can you guess the city?#30DayMapChallenge Day 12 - a map not made with GIS software and I swear I can almost hear the dot matrix printer sounds. pic.twitter.com/XPj1J168H0

— Tõnis Kärdi (@tkardi) November 12, 2020