Learning Objectives

After completing this unit, you’ll be able to:

Data Inspection

To ensure that you're dealing with the right information you need a clear view of data at every stage of the transformation process.

Data inspection meets this need: it is the act of viewing data for verification and debugging purposes, before, during, or after a translation.

In FME Desktop, you can use two data inspection tools: in Workbench via the Visual Preview window, or in a complementary application called the FME Data Inspector. In this module we will discuss both.

FME data inspection tools let you view data in any supported format. They are used primarily to preview data before translation or to verify it after translation. You can use them to set up and debug workspaces by inspecting data during the translation.

FME data inspection tools are not designed to be full-featured spreadsheet, database, or mapping applications. They have no analysis or editing functionality, and the tools for symbology modification or printing are intended for data validation rather than producing output.

What Can Be Inspected?

A number of different aspects of data may be inspected, including the following:

Note

Inspecting data before using it helps to detect problems before they affect the translation.

Inspecting your data before, during, and after building your workspace ensures you are working with the correct data and lets you spot data quality problems early on.

FME Data Inspector

FME Data Inspector is a standalone application for inspecting data.

Starting FME Data Inspector

To start the Data Inspector, locate it in the Windows start menu:

Finding FME Data Inspector in the Windows start menu

Major Components of FME Data Inspector

When FME Data Inspector opens a dataset, it looks something like this:

FME Data Inspector windowsMap tiles by Stamen Design, under CC-BY-3.0. Data by OpenStreetMap, under CC-BY-SA.

Note

These components function the same as Visual Preview, with the following differences:

  • There is a menu bar.
  • The Graphics window is called the View window and can have multiple tabs called Views, each displaying different datasets.
  • You can open data (File > Open Dataset), which opens it in a new View, or you can add data (File > Add Dataset), which adds data to the open View.
  • A few additional tools are available, including Mark Location and Measure Distances.

Selecting Features

You can select a feature in the Table or Graphics view to learn more about it.

Toolbar showing Select tool location

The Select tool button is a toggle. By default it is active when you start the FME Data Inspector; if you click it again – or select a windowing tool – you turn the select tool off.

The results of a selected feature are shown in the Feature Information window.

Feature Information Window

The upper part of this window reports on general information about the feature; which feature type (layer/table) it belongs to. If the feature is spatial, it will also report which coordinate system it is in, whether it is two- or three-dimensional, and how many vertices it possesses.

Feature Information Window

The middle part reports the attributes associated with the feature, including user attributes and format attributes (for example fme_type).

The lower part reports the geometry of the feature. It includes the geometry type and a list of the coordinates that go to make up the feature.

Table View Window

Also available is a window called the Table View.

Table View Window

The table view is a way to inspect data in a tabular, spreadsheet-like, layout. Although it does not have the same depth of information as shown by the Information Window, the Table View is particularly useful for inspecting the attribute values of multiple features simultaneously.

You can switch back and forth between feature types in the Table View by clicking the dropdown menu at the top of Table View.

Changing displayed table in Table View with the drop-down menu

Note

To improve performance, tables are not all displayed automatically, only when selected from the drop-down list, or when queried in the current view window.