Geog 469 GIS Workshop. System Requirements

Transcription

1 Geog 469 GIS Workshop System Requirements

2 Outline 1. What are some fundamental issues associated with system requirements? 2. What are your GIS data requirements? 3. What are your GIS software requirements? 4. What are your GIS hardware requirements? 5. What are the GIS staffing requirements?

3 1. What are some fundamental issues associated with system requirements?

4 Scoping Statement 2 parts Scoping statement consists of two parts containing four core elements; each element builds from previous Information Need (Assignment 1) 1) Goals What your project is going to accomplish? 2) Objectives or need-to-know questions How is your project accomplishing that goal? 3) Deliverables or information products Specific items or services that must be produced in order to fulfill the goals of the project produced in completion of an objective Systems Requirements (Assignment 2) 4) Resources Identify the GIS resources (data, software, hardware, people, institutional arrangement) used to produce the deliverables

5 Project in relation to application Project focus on processing data on topic Topic-focused activity, single database Temporary in nature, space and time context Produces a unique product or service End is determined by specific criteria of goal Application focus on repeat projects for topic Topic-support activity, many project databases Ongoing, supports many projects, many contexts Produces similar products or services over and over Processes address goal, but are ongoing

6 The Triple Constraint Every project is constrained by its: Scope: what s included in scoping goal and what s not included? Schedule: anticipated time to complete scope goal; this is time goal. Cost: budget allocated for project completion; this is cost goal Project manager s primary duty is to balance these competing constraints, while satisfying intended business need

7 The Triple Constraint for Goals of Project Management System requirements report helps define the scope, cost, and timing constraints in advance. Target is a deliverable characterized in terms of the scoping, time and cost goals. The image is from Tom Nolan s lecture notes

8 System requirements System requirements - an implementation plan that recognizes and balances constraints of available resources given information products identified during needs assessment System requirements report will be composed of Data requirement Software requirement Hardware requirement Staffing requirement Timing requirement

9 Data Requirements 2. What are your GIS data requirements? Data requirements are based on information needs, i.e. data and information are the same.

10 Data requirements: Components of Master Input Data List Tomlinson (2011) 1. Data identification 2. Data characteristics 3. Data volume considerations 4. Data availability and cost

11 Data Inventory form From Figure 6.18 in Tomlinson (2011) p. 72

12 Data availability vs. data ready Data availability: the date on which you receive data from its source Data ready: the date on which the data are in the system, processed, and ready for use in the creation of an information product Identify functions that move data from available to ready (often called data conversion) Examples: Satellite image requires file transfer and ID creation Paper map requires scanning, digitizing, topology editing, attribute editing, and so on Digital data requires less work most of the time, but still might require conversion to appropriate spatial object type

13 Choosing an appropriate map projection Intended uses of information products Be aware of distortion of geometric properties (e.g. area, shape, direction, distance) in map projections Geographic area of interest Location of standard line/parallels Difference in datum? e.g. NAD27 vs. NAD83 Difference in measurement units due to size of region? e.g. SPC in feet vs. UTM in meters

14 Appropriate map scale The appropriate map scale can be chosen based on feature resolution and error tolerance Resolution: the minimum amount of detail in a feature that can be mapped at a given scale; related to data requirements for information products Accuracy of position: how much error can be tolerated in the data? related to cost

15 Topological editing Is topology needed? Shapefiles Non-topological model Geodatabase Topological rules are assigned to feature data set Topological rules within/between feature class can be defined Use topological editing tool; help you identify potential topological errors given predefined rules

16 Projects are different What are your data questions? Enumerate these, discuss, and bring to class.

17 Software Requirements 3. What are GIS software requirements? Software transforms data into information.

18 Evolution of software from desktops to networks 1980s ~ 1990s GIS vendors provide proprietary customization capability (e.g. AML, Avenue) No standard customization systems existed Programmers had to learn different macro languages to develop applications 2000 ~ 2010 Industry-standard programming languages like Visual Basic, Python, and/or Javascript for customization Programmers work with software components, and more easily assemble them into larger systems Client-server software looms large

19 Evolution through componentization 2010 ~ Services: CyberGIS, Cloud GIS, GeoWeb, Internet GIS, Mobile GIS, Online GIS, Spatial Computing, Geospatial Cyberinfrastructure, Web GIS, Grid GIS Commercial and Open source Software integration: plug and play components using service-oriented architectures

20 Basic terms for GIS software Presentation, business logic, data Client software and server software Stand-alone vs. client/server approach Thin client vs. thick client Middleware

21 Elements of an application Three key elements of application Presentation: provide interaction (display) with users Business logic: perform operations (more than analysis) Data: data access and management Application can be functionally divided into Client: make a request Server: fulfills the request

22 Stand-alone GIS vs. Client-server GIS If the three elements reside in the same machine, the application is called stand-alone e.g. ArcGIS Desktop If the three elements reside in different machines, the application is called client-server e.g. web browser acts as client remote from the server where data and business logic reside Can be implemented with different network configurations on LANs and WANs, e.g. ArcGIS Server (now ArcGIS Enterprise)

23 Thin client vs. thick client Three application elements can be divided into client and server at any point (a to e: a, c, e are components; b and d are connections) System with partitioning point closer to a is said to have thin client (i.e., light work load in client a -b) The system whose partitioning point is closer to e is said to have thick client (i.e., heavy work load in client a - d)

24 Middleware For client to communicate with the server, we need translator to link them. Intermediate connection component is called middleware or application server e.g. ArcSDE functionality links ArcGIS (client) and DBMS (server) in enterprisewide GIS (although ArcSDE has been subsumed into ArcGIS Server)

25 Desktop GIS Client software Focus functions Products Cost ($) GIS viewer Display, query, mapping ArcReader Free Desktop mapping GIS Data use, mapping ArcView ArcEditor 1k-2k Professional GIS Data collection, editing, DB administration, advanced geoprocessing ArcGIS Desktop; ArcGIS Pro 7k-20k

26 Server GIS GIS runs on a computer handling concurrent processing requests from a range of networked clients Lower cost per user Typical costs range between $ 5k-25k Examples of implemented system include Mapquest.com Realtor.com Census.gov e.g. Autodesk MapGuide, ESRI ArcGIS Server, ArcGIS Pro, MapInfo MapXtreme

27 Mobile GIS GIS software for mobile and personal use on hand-held systems Based on location positioning technology (GPS) and wireless networking Typical single-user license cost for ESRI ArcPad is $700

28 4. What are your GIS hardware requirements?

29 Two basic network types Local Area Networks (LAN) Support high-bandwidth communications over short distances High-speed access data Within a building or localized environment Wide Area Networks (WAN) Support communications between remote locations Lower-bandwidth than LAN Internet is a global WAN

30 Four types of client-server architectures 1. Central file server with workstation clients 2. Central DBMS server with workstation clients 3. Centralized application processing with terminal clients 4. Web transaction processing with browser or workstation clients

31 1. Central file server with workstation clients Data is retrieved from the server and processed on the workstation Client contains presentation and business logic (i.e. thick clients) Server contains data management Requires the transfer of large amounts of data from the server to the client High demand for bandwidth Best deployed over LANs

32 2. Central DBMS server with workstation clients Data is retrieved from the server by the DBMS and map rendering is processed on the workstation Only the data required to support the client display need be transferred because DBMS filters data needed Reduce demands on the network Best deployed over LANs

33 3. Centralized application processing with terminal clients Data and application software are both stored and run on servers Significantly reduces network bandwidth requirements Will be best deployed over WANs

34 4. Web transaction processing with browser or workstation clients Application software and data files reside on servers Web browser displays information products via Internet or Intranet (i.e. thin client) Requires sequential support for a large number of user transactions Can be best deployed over WANs

35 Four types of system architecture based on previous descriptions Thick clients Large amount of data transfer Small # users Thin clients Small amount of data transfer Large # users 1. Central file server with workstation clients 2. Central DBMS server with workstation clients 3. Centralized application processing with terminal clients 4. Web transaction processing with browser or workstation clients

36 Staff requirements 5. What are the GIS staffing requirements? People are a very important resource.

37 Staff Roles Project Management Lead Developer Analyst GIS processor specialist Database administrator Cartographer / Geovisualization specialist End user (client) from W. Huxhold MPLIS Guidebook, Chapter 16 Needs Assessment.

38 Consider how you and your client will be using data and information, and processed by software and hardware for what deliverables? Document those resource requirements within a system requirements report.

39 Questions/Comments? End