GIS Visualization, 3D Visualization and Animation Tomislav Sapic GIS Technologist Faculty of Natural Resources Management Lakehead University
Definitions 3D Visualization: Presenting or observing spatial, geographic, data by adding the vertical plane to the conventional x,y cartographic plane. Animation: Presenting or observing spatial, geographic, data by adding the temporal dimension.
Increasing the Number of Variables Ultimately, the idea is to go beyond the traditional maps and be able to show more of variables that make up the data. One, however, quickly reaches the number of variables that an average individual can process visually and mentally at the same time 7+/- 2 by some psychological studies. Datasets, on the other hand, often can have dozens and hundreds of variables.
3D Better than Traditional 2D? 3D visualization is not necessary better than 2D visualization. Things to consider: Horizontal and vertical scale of the data, vertical variability. The mode of display. 3D visualization in a mountainous area can be quite appealing when navigating a 3D model on a computer screen and quite useless if published as a picture. Data extent and resolution. Who are going to be the viewers? Experts familiar with the subject matter might find technical and detailed 2D map more useful. The general public might appreciate better terrain clues in interpreting the visualization. Experts will easier understand derivative and abstract values.
3D Visualization 3D GIS visualization is usually associated with elevation related models but that does not necessarily have to be so GIS attributes unrelated to elevation can be visualized as well. Stand extrusion based on stand site class. DSM (digital surface model) visualization
3D Visualization Elevation Interpolation When creating 3D visualizations of terrain, elevation is interpolated. Elevation interpolation methods commonly used in ArcGIS: Interpolation Method IDW (Inverse Distance Weighted) Spline Topo to Raster Comments -Works on the premise that the further away an observation is from an interpolated point, the less of influence it has on the point. - With a high Power option, it can produce noticeable concentrations of similar interpolations around observation points. - It ensures a smooth surface. - The surface must pass through the observation points. - The surface must have minimum curvature. - Interpolates a hydrologically correct surface from point, line, and polygon data.
Raster vs. TIN TIN Triangulated Irregular Network. A different data format from rasters. The surface is partitioned into a network of contiguous nonoverlapping triangles. Triangles are between nodes and are created by applying the Delaunay triangulation, which is related to Voronoi tessellation. Nodes represent elevation points, lines between them represent slopes. TINs are handy because their node resolution changes with node value variability.
3D Visualization in ArcGIS Two ArcGIS applications are available for a true 3D visualization. ArcScene is suitable for more complex visualizations; ArcGlobe is a primarily viewer of 3D displays on a 3D model of the Earth. ArcScene ArcGlobe Vector data model files can either contain the third dimension (the z coordinate), can assume it from a surface (raster or TIN) layer as base heights (in ArcScene), or can be draped over an existing terrain layer in ArcGlobe.
ArcScene Important settings: Extrusion
ArcScene Important settings: The source of base heights. Offset
ArcScene Important settings: Vertical Exaggeration
Virtual Reality (VR) GIS Georeferenced 3D simulation of the real world through the use of real world images. VR GIS a new GIS technology, bringing multimedia into GIS. Still in search for the appropriate name - Visual GIS, Geovisualization, Video Mapping, GISVEs, Virtual GIS? Step further Virtual GIS a high-end user interface that involves real time simulation and interaction through multiple sensorial channels. These sensorial modalities are visual, auditory, tactile, smell, taste, etc. Levels of immersion in viewing Visual GIS - Lowly immersive (Desktop VR) - Partially immersive (Head Mounted Display) - Highly immersive (Cave Automated Virtual Environment)
VR GIS represents a different display and communication form than traditional maps. One of the differences is the cognitive perception; VR GIS gets perceived as the real world, whereas traditional maps are read through a conscious abstraction. As a new form of a map based communication, VR GIS has become a subject for cartographers and cartographic research International Cartographic Association has established a Commission on Visualization, with a mandate to study and report on the new trends and innovations. Related research focuses on - Comparative aesthetical perceptions and information registration of real photography and Visual GIS renderings. - Reliability of the visual information - Cognitive perceptions of the visualized information
Video imaging Landscape before harvest Landscape with harvest implemented Before harvest After harvest Geometric video imaging
Historical development: Stages and scales Stand level modeling Landscape level modeling Realistic renderings
Ecoviewer Approach (Discontinued) Product of Viewscape3D Ltd., British Columbia. Unfortunately, the company has folded and the software, although available for use, is not supported any more. The program creates a 3D model and builds on it a forest by depicting the FRI information with the tree images and ground covers. Inputs: Contour files Shape files Grid ASCII grid Rectified remote sensing images Outputs: Project viewing file Projects placed on a desktop Cutblock shape files
Available and required datasets for the project: Available datasets: - FRI shape file - 10m DEM image - roads shape file - streams shape file - tree library Required input data: - FRI shape file, integrated with roads and streams - DEM point shape file - tree library DEM and FRI datasets had to be converted and modified
Tree Library 1. Take pictures of trees with a stand-growth form 2. Remove the background and turn it into black (RGB = 0,0,0)
Image editing in Photoshop Tools used: - Lasso Tool Free-hand area selection. - Pen Tool Vertices based area selection. - Colour Balance Changes balance between red, green and blue. - Hue/Saturation Allows for hue, saturation and lightness modifications. - Magic Wand Tool Selects contiguous or non-contiguous pixels within a specified RGB tolerance range. - Colour Range Selects pixels based on a specified RGB tolerance range similar to non-contiguous Magic Wand Tool but it allows for a whole image reference for detailed selection.
3. Build Tree Library Species picture created in an image software (e.g. Photoshop) Assigned height will be used by Ecomodeler to size the trees in the model
4. Build Ecosystem Collection Different height ranges can be used to display tree growth forms (e.g. seedlings versus mature trees) Arbitrarily created ecosystem called PJBW, which in this case means 50% Jack Pine and 50% White Birch > 3 and <= 90 Species picture brought in from the tree library Add a new height class Add a new species Texture is chosen from the selection
run the program!
Some of the available VR GIS software: - Landscape Management System (University of Washington) http://landscapemanagementsystem.org/ - SmartForest (Pennsylvania State University) http://nrs.fs.fed.us/pubs/gtr/gtr_nrs1/orland_1_187.pdf - Ecoviewer - Visual Nature Studio http://www.3dnature.com/ - Hexagon Geospatial GeoMedia 3D http://www.hexagongeospatial.com/products/power-portfolio/geomedia-addons/geomedia-3d Map visualization examples: http://flash.lakeheadu.ca/~forspatial/2350/lecture3/lecture3.pdf (from slide 50 onwards)
Animation Animations are in ArcGIS can be created in ArcMap, ArcScene, and ArcGlobe. Animations can be used to analyze and understand data as much as to present them. They can be from very simple (e.g., turning a layer on and off) to very complex (e.g., chronological navigations with several layers involved and complex settings changes). Two basic animation types: Temporal Data Based depiction of events in chronological order and of actual passages of time (at a certain time scale). Not Based on Temporal Data e.g., fly-by, changes to layer settings.
Animating Object Properties Between ArcMap, ArcScene, and ArcGlobe, there are several different objects whose properties can be animated: o Temporal Data o Layer o Camera and Map View o Scene - Properties that can be animated: https://desktop.arcgis.com/en/arcmap/10.4/map/animation/aboutbuilding-animations-in-arcgis.htm
Animating Temporal Data Central part of temporal data animations are temporal attributes, i.e. time references attached to features and saved, preferably, in date/time data type fields. When working with date fields through Field Calculator, make sure only the records that have date values in the date field are selected. To populate in Field Calculator a date type field with day and month integers and a double YRORG field: str(!rndday!)+"-"+str(!rndmth!)+"-"+ str(int(!yrorg!)) To select in ArcGIS SQL years, months, days, from a date field, e.g., years after 2000: EXTRACT(YEAR FROM "datetemp") > 2000 (replace YEAR with MONTH and DAY for the other respective selections. To select weekdays: create a new integer field and then run on it, in Field Calculator, the Vbasic expression DatePart ( "w", [datetest] ), where datetest is the date field. The int field is populated with 1 (Sunday) 7 (Saturday). To add (subtract) time in years on a date field: create a new date field and run on it, to e.g., subtract 50 years, Vbasic s DateAdd ("yyyy", -50, [yeardate] ). To find differences between two field dates in, e.g., months: create an integer field and run on it in Field Calculator Vbasic s DateDiff ("m", [year],[datetest]).
Layer Time Settings
Time Slider Tool Set Options Record the movie of the last ran animation.
A simple animation can be created by changing object (layer) properties. 1) Turn on the Animation toolbar 2) Create a new keyframe of a certain type (e.g., Map Layer). Specify the source object and name the destination track and the new keyframe. 2) In the Animation Manager, set the times within the duration of animation 0.500 means it will take place halfway through the animation.
An animation can be played, paused and recorded, its duration and number of frames changed, etc.
Other than keyframes, in the Animation Manager one can change properties of Tracks,
and Time Views.
Graphs and Their Use in Animation In ArcMap, graphs can be created linked to either layer (GIS dataset) tables or pure tables and can also be animated together with animated layers they reference to. Graph lines reflect the colours used for the attributes in the legend, adding another piece of information to the visualization.
Resources: Brewer, C. A. 2005. Designing Better Maps: A Guide for GIS Users. ESRI Press. Slocum, T. A. 1999. Thematic Cartography and Visualization. Prentice- Hall, Inc.