final test essay

Photogrammetry

The first aticle in my assessment has the following title: Microcomputers and Photogrammetry. A new Application: The Videoplotter. It was written by Angrad, Ganon, and Nolette. This article describes the original of a new type of a fresh type of instrument called videoplotter which consists of a microcomputer using a high resolution monitor and driven by ideal software. That shows just how stereo-images are stored in searching for form and displayed on a screen on which 3-D measurements and plotting can be obtained, using a stereoscope, digital mapping techniques, and a measuring mark which has the advantage of being part of the image matrix ( Agnard ou al., 1165 ). The article gives a total description and use of the videoplotter.

Two main parts are identified: the Equipment part plus the Software component. The hardware of the videoplotter consists of: a great IBM-PC XT with a couple of floppy drive units, a color screen, and an image stereoscope mounted in front of the keep an eye on. The two audio system images are displayed for the screen and a computing mark is brought into exposure to the corresponding picture points, which are observed in 3-D by the poerator ( Agnard er approach., 1166 ). The software component is mainly a suitable program that performs the necessary processing and computation of relative and absolute positioning from the screen-coordinate measurements. Assessment of the system was carried out by means of a great expeeriment in which a paper diapositives of a version were produced and digitized with a great HP Scan-Jet digitizer. A subject was after that chosen and a rectangular grid was projected on the thing. Well-defined details and other targets were located at distinct spots for the object. The BC-1 deductive plotter utilized to determine the floor coordinates of there targets. By comparing the BC-1 ground values with that received by the videoplotter, the order of precision of the fresh systemcan always be obtained. The results showed which the accuracy fall season within the 1-mm ecpected buy of accuracy and reliability ( Agnard et ‘s., 1166 ). The article concludes by talking about some ways to improve the program. More sophisticated application, higher image resolution and rate digitizers, higher speed and ability computers, and higher resolution color displays are necessary to improve the program.

The second article has the pursuing title: Digital Terrain Types: An Overview. It had been written by N. Doyle. On this page, the definition, source, acquisition, storage area, application, and furure of DTM info, are talked about. The author began by giving the next definition ( Doyle, 1481 ):

An electronic Terrain Unit ( DTM ) can be an bought array of numbers that symbolizes teh space distribution of terrain attributes.

The space distribution is definitely represented by simply an XY horizontal synchronize system plus the terrain feature which is noted is the terrain elevation Unces. We can how to use alternative method of define location by lat., longitude, and terrain level. The term DTM had it is origin during working hours performed by Prof. C. L. Miller at MIT about 1955-60. A DTM

program has 4 major factors:

* Digital Data Purchase:

DTM info can be acquired from existing roadmaps by manuallyor automatically following contour lines using digitiziing tables or perhaps by using scanning services devices. The other major method to obtain digital info is by photogrammetric steremodels where encoding devices that happen to be bulit generally in most photogrammetric systems record teh data in writing or permanent magnet tape. A few photogrammetric musical instruments are equipped with programmed image correlators, and produce a high density level points. Floor surveys will be another supply of DTM data. Direct source of digital height data happen to be radar and laser altimeters carried in aircraft and spacecraft and spacecraft ( Doyle, 1482 ).

*Digital Data Preprocessing:

Attained DTM data needs comprehensive computer preprocessing to arrange the info in the appropriate format. Preproceesing includes info editing, file format conversion, synchronize transformation, and interpolation ( Doyle, 1483 ).

2. Data Storage space and Management:

DTM data has to be organized to enable them to be determined, stored, and retrieved in an efficient method. The basic storage area medium is definitely magnetic tape. In order to mange the day files, they must be croossindexed by content and insurance coverage ( Doyle, 1483 ).

* Applications of DTM info:

One procedure that is involved in the application is definitely, given XY, and asked to find Unces. In addition , offered an array of XYZ coordinates models at fixed intervals, conspiring to find the worth of Z . at any various other value of XYZ.

Some the direct application of DTM are asfollows ( Doyle, 1484 ):

1 ) Determination of contour lines.

2 . technology of single profiles.

3. Era of perspective views.

some. Earthwork computations.

5. Nav control system.

6. Landscape simulation.

six. Terrain versions.

In conclusion, the rapid expansion in the capability to handle surfaces data in completely digital form retains forth the promise of reducing the drudgery of cartographic businesses, and of minimizing time and cost so that managers and decision makers will know how to make the utmost utility with the resources worldwide ( Doyle, 1485 ).

REFRENCES

*Agrad, J. P. P. A. Gogan, and C. Nolette, (1988). Vol. fifty four, No . 8, p: 1165-1167. Microcomputers and Pjotogrammetry. A new tool: the Videoplotter. Photogrammetric Engineering and remote Sensing

*Doyle, Farrenheit. J., (1978). Vol. 44. No . doze, p: 1481-1485. Digital Landscape Models: A review. Photogrammetric Anatomist and Remote control Sensing

*Fussell, J. And D. Rundquist, (1986). Volume. 52, No . 9, L: 1507-1511, About Dfining Remote control Sensing. Photogrammetric Engineering and Remote Realizing

*Keating, Big t. J., (1979). Vol. forty five, No . 6, P: 735-740. Digital Orthophoto Production Using Scanning Microdensitometers. Photogrammetric Engineering and Remote control Sensing

*Marsy, S. E., (1979). Volume. 45, No . 2, Digital Map Modification. Photogrammetric Executive and Remote control Sensing, P: 193-200.

Lin, Hsin-Piao, 98, Vol. 34, P: 1524-1525, Photograametric prodiction of cellular satellite fading in side of the road tree-shadowed environment, Electronics Words

Kalkhan, M. A. (1998). Vol. nineteen, P: 20499-2060, Assessing the accuraxy of Landsat Thematic Mapper category using double sampling. Foreign Journal of remote Sensing.

Fraser, C. S., (1998). L: 37, A lot of Thoughts on the Emergence of Digital Close Range Photogrammetry. Pgreay

Obaidat, Mohammed Taleb., (1998). L: 3-25, Online video system to monitor archeological sites using ground-based photogrammetry. Journal of Surveying Engineering.

Mugnier, Clifford J., (1998). Low cost digital image photogrammetry. Journal of Ship Production. Vol. 18, P: 202-213