Term
| Basic structure of records and fields in a relationship database management system |
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Definition
| A database management system is software designed to assist in maintaining and utilizing databases, or sets of organized files. A file contains a set of records, which are in rows. Each record contains a set of fields, which are divided by delimiters. The address of a record is the relative location of the beginning of the record, using the beginning of the file as a reference. Record addresses can be measured in bytes. |
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Term
| What are the advantages of an indexed file? |
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Definition
| An indexed file allows you to build an index based on a unique key or combination of parts of different fields. The records are sorted by the key field, which is linked to a reference telling you where the second record is. |
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Term
| What is the difference between a primary and secondary key? |
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Definition
You can create a secondary index if you have searches that focus on other fields (because the search still takes a long time). For many things, the secondary elements will not be unique because many records have the same attribute value. (Examples: names of cities, type of political entity.) A secondary index creates an inverted list, allowing you to work backward from the secondary index to a subset of records and then to the primary record.
Secondary indices can be created for multiple variables. The advantages of a secondary index are that you can search for attributes faster and index files are smaller and easier to maintain. However, they also take up additional disk space. There is also some computational expense when you update these indices. |
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Term
| What is the first normal form rule for databases? |
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Definition
| The first normal form rule for databases is that every field can contain only one value. |
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Term
| What are the rules concerning a primary key for a database? |
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Definition
| A database’s primary key must be unique, meaning that it is one unique field or a unique combination of multiple fields. |
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Term
| What is a tolerance level and how is it used in making geometric tests in GIS databases? |
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Definition
| A tolerance level is the allowable difference between measured distances that are said to be equal. Tolerance levels are usually assigned to tests of geometries, which are tests of spatial relationships. If the geometries share a common point, they have a disjoint. If they intersect, they have intersects. If they intersect at boundaries, then they’re considered to be touching. Overlapping geometries are geometries that cross. GIS users must control for tolerance level. |
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Term
| How is the structure of the raster data model different than the vector based relational model? |
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Definition
| Unlike a vector data model, raster data models have a different structure in that attribute values are explicitly stored for each cell. This means that the matrix of values start in the upper left, across the row, and down. The datasets are rectangular. Spatial information is implicitly recorded, as is topological information, which means that adjacency and connectivity can be derived from the cells’ relative position. |
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Term
| What was the tune for the song preceding the network lecture? |
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Definition
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Term
| In the topology of a network, what are the primary components and what information is stored in each? |
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Definition
■Streets as edges – directional indications needed; length or estimated travel time
■Nodes where edges meet – impendence values possible; possible turning movements |
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Term
| What are the alternative way of treating crossing points in the ArcMap network application? |
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Definition
■Nodes only in places that share an endpoint or junction
■Crossing points as nodes – assume crossing points are intersections |
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Term
| What is Dijkstra’s algorithm and how is it used in network analysis? |
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Definition
| This is used to find the shortest path from an origin s to destination d. It finds the shortest path by finding all the shortest paths from s and comparing them until it reaches d. |
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Term
| Summarize the major functions that can be applied in analyzing a network in GIS. |
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Definition
■Create a network dataset
■Create a multimodal network dataset
■Find the best route – add a barrier; derive directions
■Find a service area
■Traveling salesman problem (best route for multiple stops)
■Location-allocation (choosing the best site) |
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Term
| What are the possible sources of data for network modeling? |
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Definition
| Streetmap USA, other commercial products, regional planning agencies, state DOTs, special surveys. |
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Term
| What is the modifable areal unit problem and how will it impact the calculation of spatial statistics? |
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Definition
| This occurs when aggregration causes averaging of potential heterogenous units, which misrepresents the distribution (e.g. you have a economically-challenged neighborhood surrounded by affluent neighborhoods, and when aggregating the data, the poor neighborhood is blended with the wealthy neighborhoods). |
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Term
| What is Moran’s index and what does it measure? Why is it critical to measure this property? |
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Definition
Measures spatial autocorrelation.
+ Value = nearby areas tend to be similar in attributes
- Value = implies dissimilarity
0 Value = uncorrelated, independent, & random arrangement of attribute values
Spatial Autocorrelation indicates whether adjacent or neighboring values in the geospatial data vary together and, if so, how. |
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Term
| Describe point pattern cluster analysis and what it tells you about the distribution of point datasets. |
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Definition
| Reveals spatial patterns, which can provide clues to a possible causal process. Best known techniques are “quadrant counts” and “nearest-neighbor analysis”. Reveals the physical and socioeconomic forces at work. |
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Term
| Compare inverse distance weighting and Krigin and how are they used to interpolate datasets. What types of data is this applicable to? |
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Definition
Interpolation: estimating quantity in places on the map where no measurements were taken.
Inverse-distance Weighting:
Estimating value at unknown points using weighted average of measurements from known points.
Kriging:
Using statistical techniques to model the pattern of distance decay in the existing data.
These techniques are only applicable to continuous variables. |
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Term
| GIS operations for local operations. |
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Definition
| ■cell by cell. Examples are reclassification (recoding), overlay analysis (logical: AND, OR, XOR; arithmetic: SUBTRACTION, MULTIPLICATION, ASSIGNMENT) |
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Term
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Definition
| ■Context or focal operations. A “window” over each cell. Examples are spatial aggregation (average, central cell, median) and filtering (improves image quality). |
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Term
| *Extended neighborhood operational |
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Definition
| ■Statistical analysis—for example, distance, proximity, and connectivity. Buffers and viewshed analysis (visibility from a cell) are extended neighborhood operations. |
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Term
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Definition
| ■Identification of regions and operations on regions. For example, calculating area, perimeter, aor shape are examples of regional operations. |
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Term
| What is cartographic modeling? |
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Definition
| Cartographic modeling is the process of linking operations on different raster layers into a logical sequence to solve spatial problems. Map algebra is used in this process. |
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Term
| What is descriptive cartographic modeling? |
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Definition
| Descriptive cartographic modeling is the process of using map algebra to address a “what is?” question. See pg 185 of the text for an example. This flowchart addresses the question “what is the quality of life in a census block or blocks?” |
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Term
| What is prescriptive cartographic modeling? |
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Definition
| Prescriptive cartographic modeling is the process of using map algebra to address a “what if?” question. This flowchart addresses the question “what would happen if a landslide occurred?” |
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Term
| Be able to sketch out a cartographic model using map algebra |
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Definition
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Term
| What is error propagation? |
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Definition
| Error propagation is based on the idea that accuracy of the new map layer is dependent on the type and level of errors that are present in the input map layers. Thus the quality of input data layers must be known to reduce error propagation. |
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Term
Data capture techniques,for raster and
vector data. |
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Definition
Primary data is the raw, original data. Examples include data from aircraft, satellite, or GPS.
■Primary raster: digital satellite remote sensing images, digital aerial photographs
■Primary vector: survey and GPS measurements |
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Term
Secondary data for raster and
vector data |
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Definition
Secondary data is data derived from another product. Examples include: a scanned photograph which is then converted into a map, and heads up digitizing.
■■Secondary raster: scanned maps or photographs, digital elevation models (DEMs) from topographic maps
■■Secondary vector: digitizing vector objects from maps and other geographic data sources, place name databases, Photogrammetry (the science and technology of making measurements from pictures, aerial photographs, and images) |
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Term
| Give sources of measurement error |
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Definition
■Human error during digitization. This can happen if the person who is digitizing a map does not have a steady hand.
■■Rubber sheeting is “the method of registering one layer of digital data to another by using a set of common points, rather than by coordinates of control points” (p. 509). If two maps used in the same layer have two different scales (e.g. the first map is 1:10,000 and the second is 1:100,000), and you are trying to connect them, matching them by these common points instead of matching them by coordinates can create error. |
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Term
| Give examples of data consistency. |
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Definition
| Verifying data consistency means testing whether the data is logical. If the data is consistent, then 1) ends and corners should meet at a common vertex. Also, 2) adjacent polygons should share an identical boundary |
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Term
| Give examples of a basic editing task in a GIS. |
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Definition
■Digitize new features from a paper map or a scanned map.
■■Construct new features from survey descriptions
■■Map areas or objects based on aerial photos or satellite imagery.
■■Update features that have changed since they were created.
■■Fix errors.
■■Update or correct attributes of features. |
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Term
| Give examples of capturing attribute data for use in a GIS. |
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Definition
■Data loggers – e.g. weather station, soil moisture, vehicle testing, offshore monitoring
■Manual keyboard entry
■Optical Character Recognition (OCR)
■Voice recognition |
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Term
| Give examples of key sources for geographic data. |
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Definition
■Federal agencies -- United States Geological Survey (USGS), Census Bureau, Dept of Agriculture, NOAA, FEMA, EPA
■State and local agencies – Department of Transportation, Dept of Natural Resources
■Universities?
■Commercial sources – Sanborn Map Company.
■Data clearinghouses – NSDI geospatial data clearinghouse |
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Term
| Explain why GIS has become so widely used in local government planning and service delivery. Identify at least two reasons in your answer. |
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Definition
Different departments can use the same map. (Merry)
■■GIS is used to create descriptive summary data
* Land use by type
* Stream lengths
* Stream segment area
* Locations of major polluters, bridges, culverts
■■GIS use becoming more common in municipal government (Acey)
* It can be used to track the status of infrastructure
Age and condition
Maintenance schedules
Location of sewer and water lines
Transportation systems
* It is tied to county land ownership records
* These newer uses of GIS require constant updating of the database. |
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Term
| What is the major trend in the use of GIS across all levels of public decision making? |
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Definition
■Using shared data files (Merry)
■■“Top-down” edicts from the central government are increasingly supplemented by “bottom-up” initiatives arising from the contributions of local communities (Acey). These include public participation GIS |
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Term
| What are the topic areas in civil engineering where GIS can be used and give an example |
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Definition
■Transportation
* Planning and locating new roadway corridors
* Emergency operations need transportation maps
* Traffic flow analysis: Driving a car equipped with a GPS on a specified path (Route 315) at certain times of the day and timing the drive to measure traffic flow
* Asset management
* Roadway inventory
* Centerline base maps
■■Watershed analysis - Hydrologic modeling
* Estimating the magnitude of high-flow events or the probability of low-flow events
* Determining the location and size of flood zones
* Identify high-potential erosion areas
* Slope stability analysis
■■Land cover change
■■Infrastructure management (this was also covered in the CRP lecture) |
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Term
| What are the major steps in implementing GIS? |
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Definition
* Planning Stage
* Design Stage
* Implementation Stage |
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Term
| * Planning Stage in GIS implementation involves? |
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Definition
■Define the basic function and scope of the system, including how many users and how many agencies
■■Interaction with other agency efforts
■■Import data, graphics, CAD from other agencies
■■Identify how data will be exchanged
■■Educate staff and major decisions makers
■■Schedule design and implementation
■■Visit with vendors
■■Test programs |
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Term
| * Design Stage in GIS implementation involves? |
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Definition
■Identify data and analysis needs
■Prepare for costs of new system
■Identify changes in organizational structure that need to happen
■Interview people with GIS expertise
■Identify current data uses and what future needs likely will be
■Incorporate current data into new system
■How will data be displayed?
■Where is the data going to be stored?
■What will standard resolution and accuracy be?
■Schedule frequency of updates of data
■Assess who will have access to what data, and how much access |
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Term
| * Implementation Stage in GIS implementation involves? |
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Definition
■Staff and user training
■Establishing operating procedures
■■Purchasing and maintaining physical infrastructure
■■Making institutional arrangements with other entities to use the system or its data |
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Term
| What are some of the institutional barriers to implementation of a major information technology program like GIS, and how might they be resolved? |
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Definition
■Employees’ unwillingness to change
■Turf-wars over data access and sharing
■Costs of implementation
■Training for employees
■Hiring of new IT people
■Training for managers who don’t use the systems directly |
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Term
| What is deontology and what role does it play in GIS? |
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Definition
Deontology is the idea that actions must follow a strict code of rules regardless of the consequence. For instance, if one believes it is immoral to lie, then they will not lie no matter if them telling the truth causes more harmful consequences then just telling a lie. The inverse of this is performing actions that are considered
to be moral although they cause harm to others. In GIS, the strict adherence to moral oblations could be good or bad depending on the application. It would be good to adhere to the ideal of treating others with respect when designing maps, or making sure that the maps and data being processed is not going to be used in a discriminatory manner. |
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Term
| Give three reasons why we need a code of ethics? |
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Definition
■Denture Unethical Behavior
■Acts as a basis for adjudicating disputes
■Enhances a profession’s reputation
■Acts as a source for public evaluation |
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Term
Describe the URISA Code of Ethics, in terms of obligations to society, and to individuals in society. |
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Definition
*Obligations to Society
■Do the best work possible
■Be objective, practice integrity, provide accurate information, be aware of consequences
■Contribute to the Community to the extent possible feasible, and advisable
■Make findings available, strive for citizen involvement, donate services to community
■Speak out about issues
*Obligations to individual’s in society
■Respect privacy
■Respect individuals
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Term
| Describe the URISA Code of Ethics, in terms of obligations to colleagues and the profession. |
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Definition
*Oblations To Colleagues and the Profession
■■Respect the work of others
■■Cite work properly
■■Contribute to the discipline to the extent possible
■■Publish results for others to learn, volunteer time to professional education
■■Oblations to Individuals and Society
■■Respect privacy
■■Respect individuals
■■Encourage autonomy, avoid undue intrusions into lives of individuals |
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Term
| Describe the URISA Code of Ethics, in terms of obligations employers and funders. |
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Definition
*Obligations to Employers and Funders
■■Deliver quality work
■■Be qualified, keep current, identify risks
■■Be honest in representations
■■Be truthful about qualifications, do an hours work for an hours pay
■■Have professional relationships
■■Hold information confidential, avoid conflicts of intrests with clients, avoid soliciting… gratuity or inappropriate benefit |
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Term
| Give one way that a GIS practitioner can prevent the mis-use of GIS. |
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Definition
■Verification of data quality by original producer
■■Verification of data quality by discipline experts
■■Setting and maintaining data quality standards
■■Introducing changes in data availability |
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Term
| What is the National Spatial Data Infrastructure? |
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Definition
■1994, created by an Executive Order that strengthened A-16 (1990)
■■NSDI: supposed to be the agreed-upon, documented, standardized data models and databases that provide metadata in order to create a coordinated information system |
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Term
| 39) Give two examples of potential new applications of GIS. |
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Definition
■Location-based services
■Global data layers
■GIS curriculum
■Imagery for the nation
■Data-mining
■3D modeling
■ Temporal modeling |
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Term
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Definition
Non-professionals participating in the collection, analysis, and distribution/sharing of data.
Example: people taking photos of streets and uploading them to the streetwatch website
Example: Canadians uploading photos of local flora to an online database |
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Term
| Give to examples of GIS grand challenges? |
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Definition
■Integrating the temporal nature of data and the world into GIS
■The scale of GIS
■Keeping data clean so that its authenticity is verifiable
■Development of richer geodemographic data infrastructures - social networks and real-time data
■Transition from geo-centered to ego-centered mapping
■Support data models for a complete range of geographic phenomena
■Combating terrorism yet preserving culture
■GeoDesign - geographic sketching |
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Term
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Definition
| A table with no predefined links to other tables |
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Term
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Definition
| Has a parent-child-child structure |
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Term
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Definition
| Represents many to many relationships |
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Term
| Object relational database |
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Definition
| Has special properties to handle geometric objects |
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