3D Printing GIS Data

Grades 9-12
  • Art Art
  • Math Math
  • Social Sciences Social Sciences
  • Interdisciplinary Interdisciplinary

INTRODUCTION

One powerful application of 3D printing is the ability to create tangible objects that help students visualize information. Doug McCune has created a utility application shp2stl to convert GIS data in a shapefile format to a three dimensional model suitable for printing.

These images were created by Doug McCune from data from the 2014 Napa earthquake:
napa  napa

napa
Images from dougmccine.com

GIS

GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information (that is data identified according to their locations).

The primary requirement for the source data is that the locations for the variables are known. Location may be annotated by x,y, and z coordinates of longitude, latitude, and elevation, or by such systems as ZIP codes or highway mile markers. Any variable that can be located spatially can be fed into a GIS. Also, different kinds of data in map form can be entered into a GIS.

Shapefiles

A shapefile stores nontopological geometry and attribute information for the spatial features in a data set. The main file (.shp) contains a fixed-length file header followed by variable-length records. Each variable-length record is made up of a fixed-length record header followed by variable-length record contents. An ESRI shapefile has 3 files:
  • *.shp (shape)
  • *.dbf (table)
  • *.shx (index)
In addition to the three basic files your dataset may include a *.prj file (projection file). This file is very useful as it can tell you what coordinate system the shapefile is in—something you will need to know if you want your data to line up correctly. The .prj file contains a WKT (Well-Known Text) string with the parameters for the map projection.

After you have your .shp file and your .prj file, you can create a geojson file. You'll need this file to determine how to and if you can extrude your shp file.

Projection files

The .prj file tells you what coordinate system your data is in.

Common coordinate systems include:
  • Latitude/Longitude - measured in degrees
  • UTM (Universal Transverse Mercator) - measured in meters
    • Arkansas = Zone 15
    • California = Zone 10 or 11
  • State Plane - usually measured in feet
  • Teale Albers Equal Area (for California) - one coordinate system for the whole state (rather than 2 zones for UTM)
The .prj file will also tell you what datum (an estimation of the shape of the earth) that your data is using.

Common datums include:
  • WGS 1984 (World)
  • NAD 1983 (North American Datum calculated in 1983 - very close to WGS 1984)
  • NAD 1927 (North American Datum calculated in 1927 - not as accurate as NAD 1983)
If you have a .prj file you can use this webpage prj2epsg.org to find the datum. You will need this information to generate a geojson file. This will allow you to determine if you can create an STL file from your shape file.

LESSON PURPOSE

  • Be able to search for GIS data.
  • Be able to understand GIS data.
  • Be able to explain GIS data.
  • Be able to use GIS data to support an argument.

MATERIALS

  • 3D printer
  • Access to the internet
  • Applications: Node, NetFabb, a Slicer

RESOURCES

DATABASES

  • Baruch Geoportal
  • Austin Texas
  • ATLAS OF HISTORICAL COUNTY BOUNDARIES