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Welcome to AgWare News! The concept of this newsletter is to update our customers of upcoming training seminars, new releases, quick program fixes, program enhancements, and other general information. We hope that you will enjoy receiving this valuable information and that you will be interactive with your thoughts and comments. Please also check out our website at www.uaar.net.
Introduction:
By Bob Nielsen, Certified Professional Soil Scientist
Aerial photography is becoming more widely available and is an important tool for the rural appraiser’s tool box. These photographs provide a bird’s eye view of the subject property and serve as excellent base maps or images for appraisal reports. From this unique vantage point, many features of the subject property can be shown that maybe difficult or impossible to explain in narrative form. Some of these features include roads, streams, water features, land use patterns, and fence lines to name but a few.
Given the abundance of sources for aerial photography and the various distribution formats, it is important that the appraiser have a fundamental understanding of aerial photography or imaging in order to select the right products for their appraisal reports. Over the next few news letters we will discuss some of the basic terminology and types of aerial photography; formats and format requirements to view, draw on, and print aerial images or maps, and imagery sources.
Overview: Aerial photographs are the most commonly utilized kinds of remotely sensed images. They are used for all manner of land resources, cartographic, and appraisal surveys in the public and private sectors. They are often employed as "base maps" upon which thematic data (property lines, field boundaries, soils, etc.) are portrayed. Most generally, aerial photographs are black and white images but color images are available in some areas and may soon place the black and white format.
Although both aerial photographic maps and aerial photos present a "bird's-eye" view of the earth, aerial photographs are NOT necessarily maps. Because by definition, maps representations of the earth's surface, meaning that they are directionally and geometrically accurate (at least within the limitations imposed by projecting a 3-dimensional object onto 2 dimensions). Aerial photos are not corrected to fit the earth’s surface and display a high degree of distortion as the user moves from the center of the photograph to its edges. That is, the topography is distorted, and measurements made from a photograph are not very accurate. Nevertheless, aerial photographs are a powerful tool for identifying and visualizing a subject property’s features.
Aerial photographs that have been corrected for distortion and fit the earth’s curvature and terrain are Orthophotographs. Orthophotographs are more readily used for measurement and spatial analyses because they do maintain a constant scale across the image. Orthophotographs are digital images that are produced by making geometric corrections to scanned aerial photographs. The distortion in aerial photographs is removed by unwarping the effects of terrain, removing the perspective projection of the camera, and then fitting the image to a particular map projection to create an "image map" that has a uniform scale and a known accuracy.2
Summary: Aerial images are widely available over the internet or can be ordered on a CD from national, state, and local governmental sources and private vendors. These products come in various formats, accuracy of scale, and costs. In future newsletter, I will explain the differences in format, various imagery and photographic map sources, and what image format works with what software.
The important thing to remember is, if you need accuracy in measuring distance or area from an aerial photograph then you are better served with one of the orhtophotographic products then with an aerial image. Also, the orhtophotographic products are more compatible with and easily incorporated into Geographic Information System (GIS).
The following web references are provided for those who wish additional information:
How to use the UAAR 2005 Image Optimizer:
If you have been using UAAR 2005 chances are you have seen the below dialog box when closing an appraisal. A new Image Editor was added to help optimize images and reduce the size of reports. Even with this new feature getting images sized correctly can be a tricky task.
Why should I care about large images anyway?
Using large images in reports will increase the time it takes to open and save reports. Reports will also take more time to share over a network or via e-mail. In some cases too many large images can cause your system to start thrashing. Thrashing will cause a system to dramatically slow down and you may see and error message from Widows warning you about low virtual memory. Some printers can also have problems when printing large images.
On the other side of things you can optimize an image too much. Images that have been over optimized look blurry or grainy. The difference can be even more dramatic when printing the report. Modern printers can show 10 times more data then you can see on the screen. So you want the images large enough that they look good when printing but not too large that they cause problems.
The Image Editor has a lot of options. I will touch on a few that I find the most useful. You don't need to close the report to get the image editor to appear. It can also be accessed directly from the Image Editor menu option under the Tools menu.
The bottom of the image editor will show you all the different images in your report. You can choose to optimize one image at a time or apply new settings to all your images at once. You can flip or rotate your image and adjust the brightness as well. There is a known issue with the image editor. You can't rotate your image without optimizing it. If you change any of the images settings the Save button will enable. However, clicking it will save the changes to the image and apply the current optimization settings. You can set Image Quality to High to minimize the changes, but the image will still be optimized.
There are a few items of special note on the form. The "Optimize For Current Cell Size" is one option you probably want to uncheck. Leaving this will optimize the image for viewing on a screen. Any extra information that could be used by the printer will be lost. You will probably be much happier with the results if you uncheck this box. Another item to note is the file size column in the image grid. This can be useful to see which images need to be optimized. It can also be useful for the settings we will be looking at in a minute. One last note about this screen, the Save button will cause the changes to be applied to the report but will not save the report. You will need to do that once you exit the Image Editor screen. As noted in the warning above once you save the report you can't restore your images without the original image file. After all, the purpose here is to make the report file smaller. Once the file is saved any extra image data that was removed by the optimization is gone for good. The Save As button will let you export the image from your report. This can be useful if you scanned an image directly into your report or don't have the original image and need to extract it to use it in a different program.
The best way to learn how this form works is to try it out. Open a new container and add a few photo pages. Add some images from your last appraisal and open up the image editor. Try to optimize some of your images with different setting and then print the report. You may find that unchecking the Optimize for Current Cell size and using the High or Med quality settings give you a smaller size with little to no visible difference in your images. Make sure you try some map images as well. Text can be hard to optimize on images. You may be happy with results on a digital photo but not with area maps.
This new image stuff is OK but I just want the program to leave me alone!
Well, OK. If you look under the menu item Edit -> Preferences -> Application and switch to the Saving tab you can control when you are prompted to optimize image sizes. In fact you can turn off the prompt all together. You can still use the Image Editor under the Tools menu item even if you turn off this prompt. Before you turn it off consider just changing the K bytes value to something larger than 100. If you look back at the Image Editor I pointed out where you could see the size of the image files. Chances are the photos from your digital camera are in the 300-400 kilobyte range. If that is the case just set the size in your preferences to 500 or 600 kilobytes. Then in most cases you will never see the question when closing a report. However, if the setting on your digital camera gets changed and you suddenly start taking 3 Megabyte images you will get a warning. In that case you probably do want to optimize the images, either with the software provided by your camera or now, directly in UAAR.
Warning: When you use the Image Editor in UAAR 2005 you cannot undo your changes once you save the report. Make sure you are happy with your changes before saving. The save button on the image editor does not save the report. It saves your current change in memory. However, once you close the image editor and save the report itself your changes will be permanent. The only way to restore the images would be to re-add the image from the original file.
If you have questions on this tip or other tips that you would like to share please e-mail us at agware@uaar.net.
The following are the AgWare seminars for 2005. Please fill out the attached registration form and fax it back to us at 605-787-6163 if you are interested in attending. All classes will be held in Rapid City, SD. and will be two days. The cost will be $300.00 for ASFMRA members and $400.00 for non-members (plus 6% SD tax).
**Please note additional training may be added during the year. ASFMRA Chapters frequently request training in conjunction with their chapter meetings, which we happily do. If there are 10 or more individuals interested in your area please contact us and we will assist you in organizing a seminar.
**Continuing Education hours are between 14 and 16 hours based on your state.
For more information on our seminars please contact Agware at 605-787-7871 or AgWare.
We would like to know what you think of the newsletter along with any comments and ideas for future issues.
AgWare, Inc.
PO Box 138
Piedmont, SD 57769
Phone: 605-787-7871
Fax: 605-787-6163
Email: agware@uaar.net
Website: www.uaar.net
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