Technical Manual to Making Hearts!

Guest post by Christy!

Inspired by Gretchen Peterson’s Valentine’s Day stickers, I started on an adventure to create pink heat-shaped maps using FOSS programs.  Using Quantum GIS and Inkskape, I created SVG images that are easy to manipulate and export to raster  images.

1. Need some data

Natural Earth has small scale data available for free.  Since all that’s needed is oceans and land masses, their 1:110M data are a perfect option:

2. Add the data to QGIS and reproject

  • Open the “Custom Coordinate Reference System Definition” dialog box (Edit | Custom CRS…).
  • Give the projection a name (e.g. Werner), enter +proj=bonne +lat_1=90 in the Parameters text box, and hit the save icon.  Now the projection can be selected in the project properties and any data added to the project will be reprojected.
  • Open the Project Properties (File | Project Properties…), scroll down to the User Defined Coordinate Systems section, select the Werner projection that was just added, check the “Enable ‘on the fly’ CRS transformation” check box, and click OK.
  • Add the data to the project.  There will probably be a line from the top-centre of the heart going off to the left, but that can be removed once the map has been imported into Inkscape.
  • Open the Properties for each layer (Layer | Properties…) and remove the outlines in the Symbology section.  If outlines are desired, they can be added in Inkscape.

3. Export the map as a PostScript file

  • Open a new Print Composer (File | New Print Composer).  Click the “Add Map” button and click and drag a rectangle in the map area.
  • Open the Print dialog (File | Print) and select “Print to File (Postscript)” in the Name field.  Click “Properties” and change the orientation to landscape.  Enter an output file name and click “Print”.

4. Open and edit the PostScript file in Inkscape

  • In Inkscape, select open the PostScript file (File | Open, and select the file).  In the PDF Import Settings dialog, no changes are necessary, just click OK.
  • Right-click on the map and select “Ungroup” three times to separate the heart from the rest of the page components.  The extra page components can be deleted (there will probably be 4 – an outline, 2 white rectangles and a grey rectangle).
  • There will be a few vertices in the top left corner.  Select them with the “Edit Paths by Nodes” tool and delete them.
  • Change the colours of the outlines and fills and add other features as desired.

5. Export as a bitmap

  • With the components of your artwork selected, open the Export Bitmap dialog (File | Export Bitmap).  Click the “Selection” button in the Export Area section, and either select a width and height of the output image, or change the dpi.  Input a file name for the bitmap and click Export.

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