User:Mav/Data Acquisition in GIS notes by maveric149/2002-04-05 Lecture
Data Acquisition in GIS notes by maveric149 2002-04-05 Lecture
Digitizing of data
[edit]turning something into coputer readable format - literally turing it into 1s and 0s. In other words representing something mathematically that was not initially mathematical.
Digitizer =
[edit]is a tablet with a grid of wires under a plastic covering. To mark positions you use a "curser" (mouse-like device). The resolution of the table is based on the number of wires that are in the grid. Wen you push the button on the cursor it sends out a magnetic signal that is picked up by the grid - marking the position.
Scanning
[edit]inside the scanner is an array of photodectors. Alalog would be a satellite moving over the earth and scanning the surface. Its angle in constantly changing. It has a lightsource, surface, and detector array. Physical resolution is the number of detectors in every inch.
Lecture: Digitizing theory, hardware museum pieces
On Scanning:
http://www.scantips.com/ Best beginner's site I've run across so far (pv).
Scanning Manufacturers:
HP, Umax, Microtek, Epson
Scanning Demo
ArcView Image Analysis Extension Demo: Georeferencing an Image
WebSites of the Week on Digitizing:
http://www.ssg-surfer.com/?source=goto
This is the main site for this company
http://www.ssg-surfer.com/html/didger_details.html
This is where the digitizing software info is.
interesting info on current product.
http://www.innovativegis.com/education/primer/sources.html
This has some good information on Digitizing.
http://www.geography.ccsu.edu/harmonj/g378/html/prod/sld001.htm
Here is a Power Point Presentation
useful information for lecture.
http://www.giscafe.com/Download/Digitizing_Tools/
This is a site that has FREE digitizing tools.
I dont know anything about them.
I havent had time to check out the site yet.
http://web.mit.edu/gis/www/arcviewdigitizing/
This is a great site !
It has wonderful screen shots and lays out the exercises very clearly.