GIS and Media fusion
"The explosive growth of the GeoWeb and geographic information has made GIS powerful media for the general public to communicate, but perhaps more importantly, GIS have also become media for constructive dialogs and interactions about social issues." - Sui & Goodchild
User Tools
This is an old revision of the document!
SQL Spatial with Carto.com & PostGIS
Carto.com offre un frontale très convivial pour piloter une base de données spatiale utilisant PostGIS (http://postgis.net, https://carto.com/docs/faqs/postgresql-and-postgis). Rapide découverte en deux parties.
Avant de commencer, il faut se connecter sur http://carto.com avec le utilisateur geoinf16.
Partie 1
On utilise la géotable earthquakes (source : http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_month.csv)
SELECT ST_AsText(the_geom), * FROM earthquake
- le frontale offre une preview cartographique et permet de créer une carte sur la base de ce jeu de géodonnées
- créer votre séisme quelque-part en Suisse (!)
SELECT ST_AsText(ST_Transform(ST_GeometryFromText('POINT(558000 137000)', 21781), 4326))
- à vous de jouer en donnant de bonnes infos
INSERT INTO earthquakes (place, mag, the_geom) VALUES ('SOMEWHERE, Switzerland', MMM, ST_Transform(ST_GeometryFromText('POINT(XXX YYY)', 21781), 4326));
- Exemple ST_Distance et le type geography : http://postgis.net/docs/manual-2.3/ST_Distance.html
SELECT ST_Distance(
ST_GeomFromText('POINT(-72.1235 42.3521)',4326),
ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326)
)
- Exercice ST_Distance (1) : quelle distance sépare chaque séisme de Fukushima (POINT(141.0357 37.4217))
SELECT *,
ST_Distance(
the_geom::geography,
ST_GeometryFromText('POINT(141.0357 37.4217)',4326)::geography
) / 1000 as d FROM all_month
- adapter le style
- Exercice ST_Distance (2) : nearest of Fukishima of mag > 6
SELECT *,
ST_Distance(
the_geom::geography,
ST_GeometryFromText('POINT(141.0357 37.4217)',4326)::geography
) / 1000 as d FROM all_month WHERE mag > 6 ORDER BY d LIMIT 1
