basemap

Basemap

This dataset contains shapefile data to generate a basemap for this case study, but also other case studies.

Description

The dataset is a shapefile containing all countries in the world (including terrestrial borders), but with lakes excluded. This creates nice, natural borders for all countries.

Data

• Shapefile: countries_minus_lakes.shp. Compress the whole basemap directory for importing in QGIS or CartoDB.

Procedure for generating the data

Source data

• Countries: ne_10m_admin_0_countries from Natural Earth
• Lakes: ne_10m_lakes from Natural Earth

Substract lakes from countries

1. Open both files in QGIS
2. Choose Vector > Geoprocessing Tools > Difference
3. Set ne_10m_lakes as the difference layer
4. Save as countries_minus_lakes.shp

Procedure to create a topojson for a certain bounding box

In this example, we create a topojson for this case study: -4.7 48.6 14.0 54.9. For a map of Northeastern US, use -99.9 23.5 -51.1 49.7.

Clip data to bounding box

Assumes GDAL is installed:

mkdir clipped_shapefile
ogr2ogr -f "ESRI Shapefile" clipped_shapefile/countries.shp countries_minus_lakes.shp -clipsrc -4.7 48.6 14.0 54.9

Convert to topojson

Assumes topojson is installed (see also topojson documentation):

topojson -o basemap.topojson -- countries=clipped_shapefile/countries.shp