Faramarz F. Samavati

Faramarz F. Samavati
The University of Calgary | HBI · Department of Computer Science

Professor

About

166
Publications
56,480
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2,181
Citations
Additional affiliations
July 2001 - present
The University of Calgary
Position
  • Professor (Full)

Publications

Publications (166)
Article
Geospatial data analysis often requires the computing of a distance transform for a given vector feature. For instance, in wildfire management, it is helpful to find the distance of all points in an area from the wildfire’s boundary. Computing a distance transform on traditional Geographic Information Systems (GIS) is usually adopted from image pro...
Article
Full-text available
The digital preservation of heritage resources has emerged as an essential method for communicating the significance of artifacts, buildings, and landscapes to descendant communities and the wider public. While virtual representations are becoming more commonplace, physical representations (physicalization) of heritage sites via 3D printing are use...
Article
Full-text available
The use of perspective projection in data visualization has been shown to potentially aid with the perception of small values in datasets with important variations at multiple scales. We integrate perspective charts, which use perspective projection in their designs, into a geospatial visualization application for global COVID-19 data. We perform a...
Preprint
Geospatial datasets are too complex to easily visualize and understand on a computer screen. Combining digital fabrication with a discrete global grid system (DGGS) can produce physical models of the Earth for visualizing multiresolution geospatial datasets. This proposed approach includes a mechanism for attaching a set of 3D printed segments to p...
Preprint
A novel method to create a physicalization of Digital Earth resulted a new type of analogue and tactile geographic information system (GIS). The model was tested by students in Australia, who shared insights into how the model supported their learning about the concept of “overlay” while providing an interesting and engaging learning platform. Obse...
Preprint
Landscape models of geospatial regions provide an intuitive mechanism for exploring complex geospatial information. However, the methods currently used to create these scale models require a large amount of resources, which restricts the availability of these models to a limited number of popular public places, such as museums and airports. In this...
Article
Virtual reality allows for highly immersive simulated experiences and interaction with virtual objects. However, virtual objects do not have real masses. Providing the sense of mass for virtual objects using un-grounded haptic interfaces has proven to be a complicated task in virtual reality. This paper proposes using a physically-based virtual han...
Article
Physical representations of data offer physical and spatial ways of looking at, navigating, and interacting with data. While digital fabrication has facilitated the creation of objects with data-driven geometry, rendering data as a physically fabricated object is still a daunting leap for many physicalization designers. Rendering in the scope of th...
Article
In this paper, we introduce a multi-factor wavelet-based deep recurrent neural network (Multi-WRNN) model for more accurate pricing of the crude oil future market. This model is capable of including several key factors (e.g. stock-change and refinery capacity utilization rate) flexibly. The Multi-WRNN model enables us to classify the time series of...
Article
Many papers have applied the meshless method to approximate a function by using a set of scattered data. To use a meshless method, we need to predefine a positive real number as a radius of the local sphere or a positive integer as the number of interior points. This is while the effect of a fixed number as the radius of a local sphere or as the nu...
Preprint
Full-text available
Physical representations of data offer physical and spatial ways of looking at, navigating, and interacting with data. While digital fabrication has facilitated the creation of objects with data-driven geometry, rendering data as a physically fabricated object is still a daunting leap for many physicalization designers. Rendering in the scope of th...
Article
A novel method to create a physicalization of Digital Earth resulted a new type of analogue and tactile geographic information system (GIS). The model was tested by students in Australia, who shared insights into how the model supported their learning about the concept of “overlay” while providing an interesting and engaging learning platform. Obse...
Article
Globe-based Digital Earth (DE) is a promising system that uses 3D models of the Earth for integration, organization, processing, and visualization of vast multiscale geospatial datasets. The growing size and scale of geospatial datasets present significant obstacles to interactive viewing and meaningful visualizations of these DE systems. To addres...
Article
Full-text available
Conventional Discrete Global Grid Systems are well suited for storing and indexing data on the Earth’s surface, but not for data above and below the surface. To properly support volumetric data, a 3D version of this data structure is needed. One promising approach for this is the Spheroid Degenerate-Octree Grid (SDOG), first proposed by Yu and Wu i...
Article
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This Special Issue is dedicated to research papers on topics related to global grid systems, from their geometric foundations to their cutting-edge applications [...]
Article
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The amount of information collected about the Earth has become extremely large. With this information comes the demand for integration, processing, visualization and distribution of this data so that it can be leveraged to solve real-world problems. To address this issue, a carefully designed information structure is needed that stores all of the i...
Article
Full-text available
Geospatial sensors are generating increasing amounts of three-dimensional (3D) data. While Discrete Global Grid Systems (DGGS) are a useful tool for integrating geospatial data, they provide no native support for 3D data. Several different 3D global grids have been proposed; however, these approaches are not consistent with state-of-the-art DGGSs....
Article
Full-text available
In this paper, we introduce two local surface averaging operators with local inverses and use them to devise a method for surface multiresolution (subdivision and reverse subdivision) of arbitrary degree. Similar to previous works by Stam, Zorin, and Schroder that achieved forward subdivision only, our averaging operators involve only direct neighb...
Chapter
Full-text available
In this chapter, we provide a thorough discussion on Digital Earth with particular focus on Discrete Global Grid Systems (DGGS), which are a standardized representation of the Earth. We describe the necessary components of a DGGS, such as the underlying 2D representation, indexing system, projection, and cell types. We also discuss a selection of w...
Article
Blood flow data from cardiac 4D Flow MRI (magnetic resonance imaging) holds much potential for research and diagnosis of flow-related diseases. However, understanding this data is quite challenging – after all, it is a volumetric vector field that changes over time. One helpful way to explore the data is by flow visualization, but most traditional...
Article
LifeBrush is a Cyberworld for painting dynamic molecular illustrations in virtual reality (VR) that then come to life as interactive simulations. We designed our system for the biological mesoscale, a spatial scale where molecules inside cells interact to form larger structures and execute the functions of cellular life. We bring our immersive illu...
Article
This paper presents a recurrent neural network (RNN) which is improved by using an efficient discrete wavelet transform (DWT) for predicting a high-frequency time series. In the combined DWT-RNN model, first, a multiresolution based on B-spline wavelet of high order d (BSd) is used to decompose the time series into several smooth data sets. Therefo...
Article
In this paper, we introduce a framework that allows NURBS subdivision curves to be defined on the sphere and ellipsoid in a multiscale manner. This is achieved via modification of a repeated invertible averaging (RIA) framework for spherical B-Spline curves, which is constructed in terms of spherical linear interpolations. By incorporating vertex w...
Conference Paper
Cardiac 4D Flow magnetic resonance imaging (4D Flow MRI) is a recent powerful technology that uniquely enables in-vivo acquisition of time-varying volumetric blood flow velocity field information in the three spatial dimensions over the cardiac cycle. Hence, 4D Flow MRI has emerged as an important medical diagnostic tool for evaluation of blood flo...
Article
Full-text available
Textures composed of individual discrete elements are found in everything from human-made glass-tilings to forests and tropical coral. We propose an interactive sketch-based system for synthesizing scenes consisting of many discrete element textures. We have implemented an example-palette, a design window where a user can use our sketch-based tools...
Conference Paper
Full-text available
Building and interacting with 3D agent-based simulations that contain a large number of agents is a significant challenge. What if we want to create an intricate new arrangement of agents, or reconfigure a large number of agents? We present LifeBrush, a cyberworld for interactively painting large and elaborate multi-agent simulations with commodity...
Article
Full-text available
In this paper, we present techniques for offsetting spherical curves represented in vector or raster form. Such techniques allow us to efficiently determine and visualize the region within a given distance of a spherical curve. Our methods additionally support mul-tiresolution representations of the underlying data, allowing initial coarse offsets...
Article
Full-text available
Landscape models of geospatial regions provide an intuitive mechanism for exploring complex geospatial information. However, the methods currently used to create these scale models require a large amount of resources, which restricts the availability of these models to a limited number of popular public places, such as museums and airports. In this...
Article
Full-text available
Artistic anatomical illustrations often focus on cross sections of long, layered, cylindrical structures. Such illustrations emphasize structures along transitions between focal points over a snaking path that optimally traverses the span of a limited space. The transitions between focal points form a multilevel visualization hierarchy. In this art...
Conference Paper
Full-text available
Panorama maps are stylized paintings of terrain often seen at tourist destinations. They are difficult to create since they are both artistic and grounded in real geographic data. In this paper we present techniques for rendering real-world data in the style of Heinrich Berann's panorama maps in a real-time application. We analyse several of Berann...
Article
Full-text available
There exists a wide variety of geospatial data sets that are too complex to easily visualize and understand on a computer screen. A physical model of an architectural project usually helps one better understand and interact with the space. Similarly, a scale model of the Earth supporting a resolution independent data visualization can be a good vis...
Article
Full-text available
It is possible to define multiresolution by reversing the process of subdivision. One approach to reverse a subdivision scheme appropriates pure numerical algebraic relations for subdivision using the interaction of diagrams [1, 2]. However, certain assumptions carried through the available work, two of which we wish to challenge: (1) the construct...
Poster
Full-text available
To get better performance for generating spectral indices visualization, we use wavelet techniques that distribute workload between client and server. This way operations on Landsat imagery data sets can be efficiently performed.
Article
Full-text available
Partition of Unity Parametrics (PUPs) is a generalization of NURBS that permits the use of arbitrary basis functions to model parametric curves and surfaces. An interesting problem for PUPs is the identification of subdivision, reverse subdivision, and multiresolution schemes for this recently developed and flexible class of parametric curves and s...
Article
Full-text available
Digital Earth is a global reference model for integrating, processing and visualizing geospatial datasets. In this reference model, various data-types, including Digital Elevation Models (DEM) and imagery (orthophotos), are universally and openly available for the entire globe. However, 3D content such as detailed terrains with features, man-made s...
Conference Paper
Full-text available
Since graphs are ubiquitous representations of data that are used in many applications, creating graph layouts is an important problem. These graph layouts are usefully discussed in terms of aesthetics that originated from mathematical concepts. In contrast, we explore the use of alternative aesthetics to inspire the visualization of graphs. We pre...
Article
In this paper, we present an approximating multiresolution framework of arbitrary degree for curves on the surface of a sphere. Multiresolution by subdivision and reverse subdivision allows one to decrease and restore the resolution of a curve, and is typically defined by affine combinations of points in Euclidean space. While translating such comb...
Article
Hierarchical grids appear in various applications in computer graphics such as subdivision and multiresolution surfaces, and terrain models. Since the different grid types perform better at different tasks, it is desired to switch between regular grids to take advantages of these grids. Based on a 2D domain obtained from the connectivity informatio...
Article
Full-text available
Energy systems are under pressure to transform to address concerns about climate change. The modeling and visualization of energy systems can play an important role in communicating the costs, benefits and trade-offs of energy systems choices. We introduce EnergyViz, a visualization system that provides an interface for exploring time-varying, mult...
Article
Full-text available
In this article, we present the construction of an interactive multilevel focus+context visualization framework for the navigation and exploration of large-scale 2D and 3D images. The presented framework utilizes a balanced multiresolution technique supported by a balanced wavelet transform (BWT). It extends the mode of focus+context visualization,...
Conference Paper
We introduce CINAPACT-splines, a class of \(C^\infty \), accurate and compactly supported splines. The integer translates of a CINAPACT-spline form a reconstruction space that can be tuned to achieve any order of accuracy. CINAPACT-splines resemble traditional B-splines in that higher orders of accuracy are achieved by successive convolutions with...
Poster
Full-text available
Discrete Global Grid Systems (DGGS) are spatial reference systems that use a hierarchical tessellation of cells to partition and address the entire globe. DGGS are designed to portray real-world phenomena by providing a digital framework on a common discrete geospatial data structure and they are commonly used to create virtual globes. DGGS differ...
Conference Paper
Full-text available
Multiresolution analysis is an important tool for exploring large-scale data sets. Such analysis provides facilities to visualize data at different levels of detail while providing the advantages of efficient data compression and transmission. In this work, an approach is presented to apply multiresolution analysis to digital Earth data where each...
Article
Full-text available
The creation of a digital representation of the Earth and its associated data is a complex and difficult task. The incredible size of geospatial data and differences between data sets pose challenges related to big data, data creation, and data integration. Advances in globe representation and visualization have made use of Discrete Global Grid Sys...
Conference Paper
Full-text available
Recently, Runions and Samavati [7] proposed Partion of Unity Parametrics (PUPs), a generalization of NURBS which replaces B-spline basis functions with arbitrary Weight-Functions (WFs) while preserving affine invariance. A key problem identified by Runions and Samavati was the identification of classes of weight-functions which are well-suited to g...
Conference Paper
Full-text available
Figure 1: The work-flow of Cover-it: Starting with (a) an input model, we generate (b) a 2D layout of simple patches and (c) an animation showing how these patches fit on (d) the 3D print of the model. As guides, (e) the patch outlines are etched into the print to support the creation of (f) the final covered print. ABSTRACT The ubiquity of 3D prin...
Conference Paper
Full-text available
a) (b) (c) (d) (f) (e) Figure 1: The work-flow of Cover-it: Starting with (a) an input model, we generate (b) a 2D layout of simple patches and (c) an animation showing how these patches fit on (d) the 3D print of the model. As guides, (e) the patch outlines are etched into the print to support the creation of (f) the final covered print. ABSTRACT...
Technical Report
Full-text available
The creation of a digital representation of the Earth and its associated data is a complex and difficult task. The incredible size of geospatial data and differences between data sets pose challenges related to big data, data creation, and data integration. Advances in globe representation and visualization have made use of Discrete Global Grid Sys...
Article
Multidimensional projection has become a standard tool for visual analysis of multidimensional data sets, as the 2D representation of multidimensional instances gives an important and informative panorama of the data. Recently, research in this torojection, a recently proposed resampling mechanism that allows users to generate new multidimensional...
Conference Paper
Full-text available
Constructing or refining complex reservoir models at the appraisal, development, or production stage is a challenging and time-consuming task that entails a high degree of uncertainty. The challenge is significantly increased by the lack of modeling, simulation and visualization tools that allow prototyping of reservoir models and development conce...
Article
Full-text available
Digital Earth frameworks provide a tool to receive, send and interact with large location-based data sets, organized usually according to Discrete Global Grid Systems (DGGS). In DGGS, an indexing method is used to assign a unique index to each cell of a global grid and the data sets corresponding to these cells are retrieved or allocated using this...
Article
Given a set of symmetric/antisymmetric filter vectors containing only regular multiresolution filters, the method we present in this article can establish a balanced multiresolution scheme for images, allowing their balanced decomposition and subsequent perfect reconstruction without the use of any extraordinary boundary filters. We define balanced...
Conference Paper
In this paper, we present the construction of a multilevel focus context visualization framework for the navigation and exploration of large-scale 2D and 3D images. The presented framework utilizes a balanced multiresolution (BMR) technique supported by a balanced wavelet transform (BWT). This devised framework extends the mode of focus context vis...
Article
Energy systems are under pressure to transform in order to address concerns about climate change. The modeling and visualization of energy systems can play an important role in communicating the costs, benefits and tradeoffs of energy systems choices. We introduce a visualization tool that provides an interface for exploring time-varying, multiattr...
Article
Sketching and doodling are two techniques commonly used by choreographers to design a dance sequence. These sketches usually represent the trajectory of the dancer in the scene. A set of annotations can be used to differentiate the various dance movements. In order to have more control over the choreographed dance, a 3D animation is preferable. Thi...
Conference Paper
Full-text available
The most common graph visualization techniques still use node- link layouts; where the nodes represent the entities and the links represent the edges or relationships between the entities. In node- link layouts, the issues of edge density, edge crossings and general edge congestion remain one of the major challenges. In this paper, we introduce a n...