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MicroImages TNTlite Version
6.0
reviewed by Ray L. Harris, Jr.
(reprinted from PE&RS December 1998
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Summary MicroImages TNTlite version 6.0 is a geospatial analysis and visualization software package for GIS, image processing, Computer Aided Design (CAD), desktop cartography, relational database management, and electronic atlas preparation. It is the exact same software as the professional version, TNTmips, but is intended for educational and research purposes. TNTlite is fully functional but limits the import size of geospatial data and does not allow export. Small data sets frequently used in the classroom, graduate work, or research papers are easily accommodated within its limits. MicroImages development philosophy foresaw the multiple platform, network environment, and strategically developed all of its software to utilize a common data file structure and user interface. MicroImages accomplished these feats by developing a multiple object file structure and an X Window OSF/Motif(r) interface and X Servers. As a result, TNTlite, like all MicroImages products, runs on 16 different computer systems. This philosophy greatly reduces the obstacles associated with learning computerized geospatial analysis. Lab exercises, once limited to expensive software at large computer facilities, can now be completed on a home computer and then brought into the lab. The same project file works regardless of the platform. TNTlite’s functionality is staggering even to a GIS and image processing professional. Most commercial software packages specialize in either image processing or vector manipulations with a few crossover utilities. However, TNTlite is capable of utilizing, editing, translating between, and integrating geospatial data types. Data types are stored in TNTlite’s Project File structure (.RVC), which supports CAD, topological vector, Triangulated Irregular Network (TIN), raster, text, and relational databases as objects within a single file. All pertinent information for each object, such as projection, histogram, cell size, or attribute tables, are stored as subobjects for each data type. When copying or processing an object, all of the subobject information is transferred or maintained without user intervention. This makes it easy to collect and maintain data in one location, regardless of geographic projection, and without special export formats or translations across operating systems. In essence, a Project File is like a folder that may contain aerial imagery, vector data, text, and sample points. All functions of TNTlite are designed to utilize the advantages of the hierarchical data structure. Display functions intuitively know where to find projection parameters for any data type. Edit functions for “head-ups” digitizing automatically extract projection parameters from reference imagery. Process functions automatically “cookie-cut” satellite imagery in Universal Transverse Mercator (UTM) projection from vector overlays in State Plane projection. Vector attribute table are stored, accessed, and queried easily. Custom scripts and procedures are combined with data so that site-specific operations remain tied to the appropriate data. All of the integration efforts are designed and intended to help users easily build a Geographic Information System (GIS) that utilizes many spatial data types. TNTlite can be downloaded via the internet for free, or can be installed from a CDROM as part of as $40 learner kit. TNTlite comes with 44 Getting Started booklets (hardcopy and softcopy Adobe Acorbat format) that explain many of the software features. The lessons include step-by-step operations and sample data so the user can walk through the procedures. Together, these 16 to 24 page booklets total more than 1,000 pages. The breadth of topics covered by the booklets is extensive enough to accompany two or more semesters of undergraduate coursework. Features TNTlite has a suite of modules that contain more functions than can be adequately covered in a brief review. This review will cover the basic processes of display (2D), edit, georeference, and import. The functions are arranged in three fundamental groups; display, edit, and process (Figure 1). These top-level menu items cascade to reveal subordinate functionality. Display functions include 2D and 3D visualization, map composition, and 3D “fly-through” simulations. Edit functions include spatial data, georeferencing, styles, database, and text editing. Process functions include Spatial Manipulation Language (SML), Mosaic, Hyperspectral Analysis, Photogrammetric Modeling, Surface Modeling, Elevation Analysis, Classification, Vector Combinations, Network Analysis, Directional Analysis, Import/Export, and others. Display Each view window can be “locked” by
position and scale to other view windows
so that movements are synchronized. The
current zoom factor and geographic coordinates
of the cursor are displayed. The
position report can be changed to any projection
at any time. The view window also
has the ability to display real-time GPS
data transmitted via a serial port. Multiple
GPS inputs can be fed into the view and
tracked across a layer. Assembling several groups on a page layout creates a map composition. Geospatial data, map grids, text, north arrows, scale bars, and legends can be created and arranged quickly. Each group is manipulated with the placement tool, which is much easier than manually entering offsets. Compositions and displays are not limited to 2D groups. Elevation data in perspective 3D groups can also be arranged in the same layout. In any map layout, all data can be visualized regardless of an individual group’s projection because TNTlite compensates for projection differences on the fly. For example, imagery in Universal Transverse Mercator and vector data in State Plane projections can be arranged in the same group window set to the projection of choice. TNTlite supports standard projections from around the world, including custom map projections; and subsequent processes automatically reconcile all projections. TNTlite limits map layouts to 8.5 x 11 inches. Output can be sent to a printer or to a postscript file. Edit New CAD or vector objects can be created from existing CAD or vector, COGO survey data, interactive line following, or raster to vector conversion (Figure 4). TNTlite’s editor is a great improvement over other software packages because it automates the housekeeping tasks associated with vector topology. Editing points, lines, and polygons can be done simultaneously while topology is automatically updated (Figure 5). A line drawn across a polygon or another line automatically inserts a node at the intersection, and splits the polygon attributes to each new half. Vectors can have 3D x, y, and z coordinates, rather than just 2D x, y. Vector data is stored more efficiently because polygons do not require a centroid point for labels. Several vector filters help remove dangles, undershoots, bubble polygons, sliver polygons, excess nodes, and unlabeled features automatically. Other filters help to simplify lines by removing excess vertices, or conversely, to densify vertices around curves to make smooth lines. A set of drawing elements, including complex shapes like regular-sided polygons or ellipsoids, can be added to a layer. Attribute attachment to points, lines, or polygons is quickly accomplished with an interactive selection tool or a query. The editor uses the same control and view windows as the display module, which helps to reduce the learning curve. Georeference The georeferencing module has a main window (Figure 6) and uses the same display control and view windows (Figure 7) as in other modules of the software. The user can set the polynomial order, projection, length units, and cursor colors. Transformations are computed on the fly, once a minimum number of tie points have been selected. During tie point selection, the target and reference object can be overlaid in the same window to check the fit. The overlay technique is especially effective for image to image registration because the target and reference image can be displayed in separate color guns. Areas of good registration appear yellow with the target image displayed in red and the reference image displayed in green. Areas of poor registration appear either green or red. Other features let the user snap tie points to vector nodes or vertices, or estimate the tie points based on the current transformation derived from the other tie points. Once control points are added and an acceptable RMS is reached, the transformation parameters are saved as a subobject. The user may reproject the data, if desired, but it is not necessary for display or overlay operations in TNTlite. However, some raster processes do require the same extents or cell size for proper operation, which can be done through the typical resampling procedures. Import Pros Cons Recommendations Reviewed
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