1. Desktop, Mobile & Web Based GIS/ Collaborative GIS
Lecture 4
Activity: Career Awareness Module 3 (SDSU)
Produced by Mark Abbott 7/20/07
Revised 8/4/07 - TT

2. Desktop GIS
Create, edit, and analyze geographic data on your desktop computer.
See your data on a map.
Analyze your data to reveal patterns, relationships, and trends that are not readily apparent in tabular format.
Create publication quality, professional maps.
Beyond showing you your data as points on a map, ArcGIS Desktop allows you to manage and integrate your data, perform advanced analysis, model and automate operational processes, and display your results on professional-quality maps.

3. ArcGIS Desktop
ArcGIS Desktop is software that allows you to discover patterns, relationships, and trends in your data that are not readily apparent in databases, spreadsheets, or statistical packages.
ArcGIS Desktop
ArcGIS Desktop is software that allows you to discover patterns, relationships, and trends in your data that are not readily apparent in databases, spreadsheets, or statistical packages.
Desktop GIS is ArcGIS Desktop, ArcGIS Engine, and ArcGIS Explorer.
Learn more about Desktop GIS.

4. Desktop GIS Advantages Disadvantages
You have all the data and processing at your station
Disadvantages
You must invest in the processor and storage space
Data and maps are not easily shared

5. Mobil GIS
Mobile GIS is the expansion of a geographic information system (GIS) from the office into the field.
A mobile GIS enables field based personnel to capture, store, update, manipulate, analyze, and display geographic information.
Traditionally, the processes of field data collection and editing have been time consuming and error prone. Geographic data has traveled into the field in the form of paper maps. Field edits were performed using sketches and notes on paper maps and forms. Once back in the office, these field edits were deciphered and manually entered into the GIS database. The result has been that GIS data has often not been as up-to-date or accurate as it could have been.
Firefighters, police officers, engineering crews, surveyors, utility workers, soldiers, census workers, field biologists, and more use mobile GIS to complete the following tasks.
Field Mapping—Create, edit, and utilize GIS maps while in the field
Asset Inventories—Create and maintain an inventory of asset locations and attribute information
Asset Maintenance—Update asset location, condition, and schedule maintenance
Inspections—Maintain digital records and locations of field assets for legal code compliance and ticketing
Incident Reporting—Document the location and circumstances of incidents and events for further action or reporting
GIS Analysis and Decision Making—Perform measuring, buffering, geoprocessing, and other GIS analysis while in the field

6. Mobile GIS integrates one or more of the following technologies:
Mobile devices
ArcGIS Mobile
ArcPad
StreetMap Mobile Software Developer Kit
Global Positioning Systems (GPS)
Wireless communications for Internet GIS access
ESRI's developments in mobile GIS have enabled GIS to be taken into the field as digital maps on compact, mobile computers, providing field access to enterprise geographic information. This enables organizations to add real-time information to their database and applications, speeding up analysis, display, and decision making by using up-to-date, more accurate spatial data.
ArcGIS Mobile—An SDK powered by ArcGIS Server to build and deploy centrally managed, fully customized mobile applications that can synchronize with the server.
ArcPad—An out-of-the-box, complete mobile mapping and field data collection solution that provides database access, mapping, GIS and global positioning system (GPS) integration via handheld and mobile devices.
StreetMap Mobile Software Developer Kit—An SDK that allows developers to create custom mapping and navigation applications for in-vehicle systems or personal navigation devices available exclusively to ESRI business partners.

7. Mobile GIS Advantage Disadvantages Portable
Allows for some map processing
Disadvantages
Minimal storage space
Need a desktop for most processing

8. Web Based GIS
Access 2D maps, 3D globes, reference layers, and functional tasks via the Web to support your GIS work.
Contribute your own data for publishing through ArcGIS Online and make it broadly available to other users.
Purchase the data you see in ArcGIS Online and publish it on your own server.
ArcWeb Services
ArcWeb Services offer a rich set of Web services application programming interfaces (APIs) for integrating Web mapping functionality and GIS content.

9. Web Based GIS Advantages Disadvantages
Minimal processor and storage space needed
Many data sets available
The processor on the web server is likely to be more powerful than your desktop unit
Disadvantages
Must have a fast network connection
Data resides off site
Dependent on resources off site, not under your control

10. Collaborative GIS
Web Based GIS where multiple users can add data to a single map.

11. Collaborative GIS Advantages Disadvantages Allows for input from:
Multiple Users
Multiple Data Sets
Multiple Perspectives
Disadvantages
Lack of control over input to the map and revisions

12. Raster vs. Vector Lecture 5
Activity- Raster Data Representation Exercise (Based on the assignment from Grossmont College; Judd Curran)
These materials were developed by Kenneth E. Foote and Donald J. Huebner, Department of Geography, University of Texas at Austin, 1996.
Produced by Mark Abbott 7/20/07
Revised 7/29/07 - TT

13. Raster and Vector Reality
One of the sharpest distinctions among GIS is the way that location is represented in a database, as either a raster or vector position.  
These materials were developed by Kenneth E. Foote and Donald J. Huebner, Department of Geography, University of Texas at Austin, 1996.

14. Raster vs. Vector "Raster is vaster, Vector is more correcter"
Vector- A coordinate-based data structure commonly used to represent linear geographic features. Each linear feature is represented as an ordered list of vertices.
-A line in computer graphics designated by its end points (xy or xyz coordinates). A vector layer does not use pixels for storing image information. Instead, it stores a vector object as a set of properties that describe its attributes, dimensions, and position in the image.
Raster- A two-dimensional array of black and white cells, called pixels or picture elements, which when displayed on a screen or paper, form an image or representation of an original document.
-A data structure for maps based on grid cells.
"Raster is vaster, Vector is more correcter"

15. The Raster View of the World
A raster based system displays, locates, and stores graphical data by using a matrix or grid of cells.
Each cell has an (x,y) location and a (z) value which stores attribute data about that location.
Each cell or pixel has discrete attribute data assigned to it.
Raster data resolution is dependent on the pixel or grid size and may vary from sub-meter to many kilometers.
Because these data are two-dimensional, GISs store various information such as forest cover, soil type, land use, wetland habitat, or other data in different layers.
Layers are functionally related map features.
Generally, raster data requires less processing than vector data, but it consumes more computer storage space.
Scanning remote sensors on satellites store data in raster format.

16. The Vector View of the World
A vector based system displays graphical data as points, lines or curves, or areas with attributes.
Cartesian coordinates (i.e., x and y) and computational algorithms of the coordinates define points in a vector system.
Lines or arcs are a series of ordered points
Vector systems are capable of very high resolution (less than or equal to .001 inch) and graphical output is similar to hand-drawn maps.
This system works well with azimuths, distances, and points, but it requires complex data structures and is less compatible with remote sensing data.
Vector data requires less computer storage space and maintaining topological relationships is easier in this system.

17. Advantages and Disadvantages
Method
Advantages
Disadvantages
Raster
Simple data structure
Compatible with remotely sensed or scanned data
Simple spatial analysis procedures
Requires greater storage space on computer
Depending on pixel size, graphical output may be less pleasing
Projection transformations are more difficult
More difficult to represent topological relationships 
Vector
Requires less disk storage space
Topological relationships are readily maintained
Graphical output more closely resembles hand-drawn maps
More complex data structure
Not as compatible with remotely sensed data
Software and hardware are often more expensive
Some spatial analysis procedures may be more difficult
Overlaying multiple vector maps is often time consuming 
One system can be converted into the other
These materials were developed by Kenneth E. Foote and Donald J. Huebner, Department of Geography, University of Texas at Austin, 1996.

18. Raster data can be converted to Vector and vice versa
Note: Converting from one system to the other can introduce error.
These materials were developed by Kenneth E. Foote and Donald J. Huebner, Department of Geography, University of Texas at Austin, 1996.