INSTRUCTOR DR. HOWARD TURNER P.L.S.

Transcription

1 ORTHOPHOTO PRODUCTION WORKSHOP CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA INSTRUCTOR DR. HOWARD TURNER P.L.S. In this workshop, you will learn how to produce an orthophoto. This will include the base rectifier software. You have set-up a project file with camera data, control data, photo and model data. You have been supplied with two softcopy photogrammetry images of the Cal Poly campus scanned at 22.5 microns. The camera data from the camera calibration report is given. The control data from a filed map is also given. The inner orientation was completed. The relative orientation was performed. The absolute orientation was performed. A digital terrain model has been collected. This laboratory exercise attempts to clearly and concisely convey the information necessary to create and use an orthophoto. This laboratory does not attempt to cover every tool in the software, but rather discusses the steps necessary to create a new orthophoto and use it as a backdrop for civil and GIS display. OBJECTIVES Upon completion of the exercise you will be able to perform the following functions. = Produce an orthophoto from an existing DTM. = Learn how to view the orthophoto in monoscopic views. = Learn how to view detail in MicroStation in image products. 1

2 1. Select Start>Programs>Base Rectifier>Base Rectifier. The following form will appear 2

3 2. Enter the following information into the form. Project The path and name of photogrammetry project (e.g. C:\calpoly\test1\project). Photo The strip and photo id that will be used to make the orthophoto (e.g. 1~3). Input Image(s) The path and name of the image to be used to make the orthophoto (e.g. C:\Images\calpoly\cal1~3.cot). Output Image(s) The path and name of the orthophoto image created (e.g. C:\Images\calpoly\orthocal1_3.cot) Overview Options Create: Full Set, Sampling Method Average. 3. Select the Rectification and DTM Options tab at the top of the form. The following form will display. 3

4 4. Enter the following data into the form. Interpolation Options Registration Options Design File Digital Terrain Model Options DTM Areas not covered by DTM Input Zero Options Cubic Convolution Sharpness 0.5 Spacing in Pixels 32 Define Image Rectangle. The values are taken from the design file. Enter path and file of design file that contains the dtm points (e.g. C:\calpoly\dgn\dtm-1~4-1~3.dgn). Elevation Data from GRD or TTN file. The path and file name to the TTN file. Zero Filled. Preserve Input Zeros in Output Image. 5. Select the Process Options tab on the top of the form. The following form appears. 4

5 6. Select Add Job. A job appears in the job list. Select Immediate. Press OK. The following form appears. 7. On the desktop, Select Start>Programs>Base Rectifier>Place Control Points 5

6 The following form appears. 8. In the Place Control Points form, enter the path and file name for the project (e.g. C:\calpoly\test1\project). In the Design File field, enter the path and name of the design file where you want the control points to appear (e.g. C:\calpoly\dgn\dtm-1~4-1~3.dgn). For Level, enter 1. For Color enter 2. For Weight enter 1. For Size enter 150. Press OK. 9. Select Start>Programs>Irasc>I_RASC. 6

7 The following form opens. 10. Select the design file that contains the DTM points. Press OK. 7

8 The design file opens. It contains the DTM points and the control points. 11. On the I/RASC C Command Window, select File>Open. The following Form appears. 8

9 12. Select the file name (e.g. C:\images\calpoly\orthocal1_3.cot) for the orthophoto you generated earlier. Click Apply. The following image will appear. 9

10 13. Window the area around control point 3587 ( the white cross target). Compare the position of the plotted control point with the target. Plot the orthophoto. 10