Example SURE 425 Exam Questions

• Define the following terms: object, instance feature, heuristic
• How does the Spatial Data Transfer Standard (SDTS) differentiate between a point and a node? Give an example of each. SDTS has three specialized spatial object types: complete chain, area chain, and network chain. What are the differences?
• What are the benefits of the National Spatial Data Infrastructure (NSDI)? Identify the steps needed for implementation of the NSDI. Several challenges are presented in the Strategic Plan for the NSDI. Identify and describe four of them.
• Metadata is data about data. Describe four of the data elements for metadata. What are metadata? What is the value of metadata from both the user and producer perspective? What are the major uses of metadata?
• What is the National Geospatial Data Clearinghouse and how will it be used?
• There are two extremes in the conceptual model of space: entities and continuous fields. Describe them.
• Examples of practical forms of spatial reference are the specific Cartesian or azimuth coordinates. Identify and give an example of three other spatial referencing devices.
• To be useful, a GIS must provide a toolbox to the user that will meet the capabilities they envision. To do so, the system must fulfill a number of capabilities. Describe the conditions which a GIS must fulfill.
• What is the importance of the measurement scale? Give a specific example.
• Your employer just returned from a convention where he/she frequently heard the term spatial/geographic information system. They know you studies GIS at Ferris and ask you to describe a spatial information system to them. What is your answer?
• Convert the hexadecimal value 02C to its binary equivalent.
• What is the difference between a simple list and an ordered list?
• There are two extremes in the conceptual model of space: entities and continuous fields. Describe them.
• Describe the difference between a regular tessellation and an irregular tessellation.
• In a vector model, nodes carry important information. Explain.
• Convert R7, C9 to the Morton Order. What is the row and column number for Morton position 28? Given a sample data set, find the (a) row order, (b) row-prime order, (c) Morton Order, and Peano Order.
• One of the properties of regular tiling is shape (also self-similarity). What is it and why is it important in tesselations?
• Given a sample data set, show the quadtree representation of that data.
• Using tesseral arithmetic, determine whether the quadtree leafs 0332 and 2 are adjacent. Using the notation x,y where x is the quadtree leaf and y is the value for the leaf, explain how you would find the quadtree structure by overlaying two maps. Find the quadtree structure and the leaf attributes for a derived map by overlaying two input maps defined by their quadtree structure and leaf attributes.
• The Octahedral Quaternary Triangular Mesh (O-QTM) was introduced by G. Dutton. Describe this method of global tessellation. What are the advantages of the O-QTM tessellation? Describe how the O-QTM has a built in mechanism for documenting scale and accuracy. The basic form of O-QTM is a series of 8 triangles covering the globe. Explain the process of subsequent divisions.
• When acquiring digital data from a data supplier, we need to consider the data characteristics to see if they are compatible with the application. Give a few concrete examples.
• What is the difference between interpolation and extrapolation?
• What is the difference between a pointwise and global method of interpolation? Describe the advantages of using trend surfaces as global interpolators. How is a pointwise random-to-grid interpolation performed? Give a graphical example. Describe the two different methods used in patchwise methods of interpolation. What are the advantages of a patchwise model over a global model of interpolation?
• Describe two different general sampling schemes used in a DTM. What is progressive sampling? Explain how it works. Describe systematic sampling for a DTM extraction and explain why this method is favored by the photogrammetric operators. Identify weaknesses in using a random sampling scheme in DEM data collection.
• Describe the process of picking a TIN model from DEM data using the VIP (Very Important Point) algorithm. Use a sketch with your description. How is the Fowler and Little algorithm employed in creating a TIN model? How is the drop-heuristic method employed in creating a TIN model.
• Sketch the Delaunay triangulation for eight points given in a figure by linking points in the figure. Is the line segment EG in the Delaunay triangulation? Explain why or why not. Given the elevation data for the figure, show how the ridge line between two points can be maintained within a Delaunay triangulation.
• What is the general position assumption? What is the empty disk property and how is it used in Delaunay Triangulation? A regular grid is not a general position assumption. How can we act on the grid points so that the general position assumption is fulfilled?
• Explain a strategy for determining if a point lies within or without a polygon. Use a sketch along with your explanation.
• Describe the procedure used in the Douglas-Peucker algorithm and give a graphical example.
• Describe two of the elements of line generalization.
• What is the purpose of line simplification? How is a three point moving window used in line simplification? Give a graphical example along with your written explanation. One method of line simplification is the retention of only a fraction of the points within the data set. What are the disadvantages of this line simplification method? Also give a graphical example. Describe the Jenks' linear simplification algorithm.
• Find the shortest Euclidean, Manhattan and Network distance from point A to point B in an accompanying figure.
• The fractal dimension indicates how measures of the object change with generalization. Explain. What is the Steinhaus Paradox? How is the fractal dimension determined? What is the difference between geometric and statistical self-similarity?
• What are the important criteria for an ideal curve?
• Describe what a TIN model is. Describe how distance ordering is used to triangulate a TIN.
• Using the 4-connectivity model (or 8-connectivity model), draw the drainage network for this DEM. If a channel starts only when the flow reaches a volume of 3, what does the channel network look like? Remember to define a tie breaking rule (state in your answer) and enforce it.
• What is a pit in a DEM? Explain the process of flooding pits to form lakes. How is the Base:Height ratio important in measuring DTM photogrammetrically?
• Describe how the minimum enclosing rectangle is used in line-line intersections. Graphically show this with an example.
• Describe three sources of error in spatial data. Describe the National Map Accuracy Standards (NMAS). What are the differences between Engineering Map Accuracy Standards (EMAS) and the ASPRS standards for large-scale mapping? Koppe's formula is an alternative to the NMAS. Explain.
• Your company has decided to submit a request for a proposal to implement a GIS for a county containing a large metropolitan area with a lot of surrounding farm land. The company has put together a team to draft the proposal with different members leading the discussion on different areas of the project. As the survey engineer, your task is to study the issue of creating a digital terrain model. Assume that this county has data to some degree under different formats. Select a method for creating the DTM and justify the selection, keeping in mind the applications of this data by the different departments within the county. Also, clearly identify the realistic assumptions for this hypothetical study.

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This page is maintained by Bob Burtch and was last updated on 19 October 2000.
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