Topic description

I have two polygon layers in the same region: 1) data layer, the area of the polygons needs to be calculated, 2) reference layer, the polygons in this layer will be used as statistic units.

Streamgraph is a type of stacked area graph which is displaced around a central axis, resulting in a flowing, organic shape. Streamgraphs and their use were popularized by Lee Byron in a February 2008 New York Times article on movie box office revenues.

Problem description

I have some census data, which are 20 excel files for 20 year respectively (1980 - 1999). Each of the files contains county names and corresponding census data, e.g., GRDP, population, education.

When you are displaying geojson with leaflet overlays, onEachFeature is a function will be applied on each feature, e.g. a point or a polygon in a features collection.

Adding several lays to leaflet and display the basic information of the layers on the map is very useful. Leaflet provaided lots handy APIs.

When I was working in Esri Deutshcland in November and December 2017 as a working student, my job is scripting for ArcGIS Pro User Management.

Before I got the job, I was temporarily living in Frankfurt am Main. While Esri Deutshcland located in a small village close to Munich, it takes quite a while to go from Munich to there. Although the interview was scheduled at 1 pm, I needed to leave Munich at 8 am. The earliest ICE (German high speed train) from Frankfurt am Main to Munich would arrive in Munich at 9 am. The only option left was over-night bus.

Using PostGIS Shapefile Import/Export Manager to import shapefile into database, but it failed.

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==============================
Shapefile type: Point
PostGIS type: POINT[2]
Failed in pgui_exec(): ERROR:  schema "public" does not exist
LINE 4: CREATE TABLE "public"."railwayStation" (gid serial,
                     ^

Shapefile import failed.

Drop all tables in a database, but keep the database.

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GRANT ALL ON SCHEMA public TO postgres;
GRANT ALL ON SCHEMA public TO public;

DROP SCHEMA public CASCADE;
CREATE SCHEMA public;

This is an investigation related to econimic geography visual analytics.

Leaflet and WMS

Web Map Service (WMS) is a way of publishing local geodata as map tiles, but more opetational. It can be published by GeoServer or other softwares e.g. QGIS.
Leaflet.js is a open source JS library, which is made for interacitve maps. With Mapbox, more maps can be designed, personalised and added to web applications via Leaflet.js.