Spatial Error Related to Datums and Projections

Creating Feature Classes from Shapefiles

Table of Contents

  1. Spatial Error Related to Datums and Projections
  2. Skill Drill: Setting Up Your Workspace
  3. Skill Drill: Downloading Data from Natural Earth
  4. Skill Drill: Connect to Your Workspace Folder in ArcMap
  5. Creating a File Geodatabase
  6. Creating Feature Classes from Shapefiles
  7. Adding XY Data using the ArcCatalog Window
  8. Skill Drill: Creating Indicatrices Using the Buffer Tool
  9. Evaluate Distortion Patterns in Map Projections
  10. Measuring Scale Distortion
  11. Skill Drill: Evaluate and Measure Distortion
  12. Troubleshooting Datum Shift
  13. Repairing Corrupted Data Using the Define Projection Tool
  14. Skill Drill: Repairing Incorrect Coordinate System Definitions

Until now, most readers should primarily have experience working with shapefiles, which is the most common file format for vector data. In ArcMap, a shapefile appears as a single file (Figure 2.08). However, when viewed in Microsoft File Explorer, you can see that a shapefile consists of many files linked together (Figure 2.06). Some of these files store spatial information, such as geographic location. Some files store attribute data as a database file. Others will save the geometry of a feature. Separating any one of these pieces makes the data unusable.

In this step, you use the shapefiles downloaded from Natural Earth to create feature classes within the geodatabase. In many ways, a feature class works similar to a shapefile. Like a shapefile, it is a collection of geographic features stored in vector format that have the same geometry type, such as point, line, or polygon. For most readers, the most noticeable differences relate to the file structure and file size. When stored in a file geodatabase, a feature class can save a maximum of one terabyte of data. A stand-alone shapefile has a size limit of only two gigabytes (GB).

In the catalog window, right-click on the geodatabase. Select Import, then Feature Class (single) (Figure 2.16).

Figure 2.16: You can import several different data types into a file geodatabase, a feature class, a table, and a raster dataset.

For the Input Features, choose the shapefile representing countries. The output location is already set to your geodatabase. For the Output Feature Class, name the file countries (Figure 2.17). You do not need to enter a file extension. Leave all other settings as default and click OK.

Figure 2.17: Check to make sure your settings match those in this image. Double-click or tap twice to view the image in a larger size.

When the geoprocessing is complete, you should see the new feature class within the geodatabase. ArcMap should also add the new feature class to the map document (Figure 2.18).

Figure 2.18: The countries feature class gets added to the map. Double-click or tap twice to view the image in a larger size.

Skill Drill: Creating Feature Classes from Shapefiles

Repeat these steps and import new feature classes to the geodatabase for the graticules and populated places. Be sure to give the feature classes human-friendly names. When done, all of the feature classes should be added to the map (Figure 2.19). Take a moment to save your map document within your workspace folder. Call the map document, Exploring Errors.

Figure 2.19: All three feature classes are added to the map, and the map document is saved within the workspace folder. Double-click or tap twice to view the image in a larger size.