Professionals often use digital mapping software called “geographic information systems” (GIS) to manage and analyze mapped data. These data, often in the form of "shapefiles" can be imported from other sources into Ortelius, with some limitations.
Importing shapefiles is an advanced topic for users familiar with GIS. Ortelius is not a GIS, it is a graphic design program with extended capabilities for mapping. Users should become familiar with its limitations and best practices before working with shapefiles.
What are Shapefiles?
Shapefiles are map data built and maintained by GIS professionals. Shapefiles provide vector map graphics and contain attribute information in a database structure. For example, a shapefile of a state with its counties may contain attribute information including the county names, population, and size of area. Ortelius map templates are created from shapefile map data, consisting of the graphic map objects and the attribute information “behind the map.” Attributes are object oriented, not stored in a database table as is done in a GIS.
A shapefile is actually a collection of at least three files with ".shp” “.shx” and “.dbf” file extensions. At a minimum, all three files are required to actually use a basic shapefile, and they must be identically named (except the file extension) and stored in the same folder. The “.shp” file is the shapefile that gets opened in Ortelius, the other files are referenced. A handful of other files may also be included, such as “.prj” for the projection information. All shapefiles must use the same map projection.
Most GIS data providers will zip the shapefile files for download.
To Import a Shapefile
Choose ‘File > Import Shapefile…’ from the main menu. Select the shapefile for import.
- Click the button labeled ‘Options’ at the bottom left of the window to expand the import dialog.
- Optionally, ‘Simplify’ can be chosen to simplify the vector line work on import using the Douglas-Peucker formula. ‘Auto colour’ may be used to randomly color fill imported polygons. Choose a color palette available from your custom palettes.
Aligning Multiple Shapefiles
Ortelius uses a "first-in" rule. The first shapefile imported to your drawing will set the document projection/CRS information. Subsequent shapefile imports will align to this map projection.
Ortelius isn’t a GIS. It renders imported data as individual vector drawing objects. Performance will be impacted by large and/or highly detailed shapefiles.
See the Ortelius 2 Shapefiles Guide for more information.