How to compare the spectral properties
Examining spectral space: One method in ERDAS of exploring spectral properties is by creating feature space layers. This function can be found in classifier > signature editor under feature. This allows the user to create a scatterplot where the data file values of one band have been plotted against the data file values of another band. This can only be done in a two dimensional histogram, but theoretically our data has 6 dimensions of spectral space. In the window titled create feature space images you must input the image you want to evaluate and click output to viewer. You may choose from a list of band pairs at the bottom of the window under feature space layers. From the signature editor dialogue choose feature > view >select viewer. Click inside the feature space viewer. Then select feature > view > linked cursors and click link. Then click inside the viewer with your image. The viewers are now linked. How to subset and mosaic images:¨ There are multiple ways to clip (SUBSET) an image, many of them use the subset command. The method that I have used and found to work the fastest is the following:
How to create signature filesA signature is a set of statistics that is created when clustering and defines a training sample or cluster. The signature is used in the classification process. Each signature corresponds to a GIS class that is created from the signatures with a classification decision rule.Using training sites (clustering in a supervised manner): Training sites can be identified as Areas Of Interest.
How To Evaluate Classification
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Mr. Phien Sayon has been a GIS & Remote Sensing Specialist for WCS-Cambodia Program since Feb 2008. He finished his bachelor degree of science in Land Management &Land Administration in 2008. He graduated Master degree of Law in Land & Immovable Properties in 2010. He became a civil servant of Ministry of Land Management, Urban Planning &Construction in 2009. He became a part-time lecturer on Photogrammetry at Royal University of Agriculture in late 2010…
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Sunday, June 19, 2011
Special tips for Remote Sensing Application (ERDAS Imagine)
Tuesday, January 25, 2011
Download Google Earth Imagery by Google Satellite Maps Downloader
Google Satellite Maps Downloader is a cute tool that help you to get small tile satellite images from google maps. All downloaded small satellite images are saved on the disk. You can view downloaded satellite maps by Satellite Map Viewer. And you can combine them into a big BMP satellite map.
Note: The downloaded images are only for your personal purpose, non-commercial use.
¤¤¤ Start Google Satellite Maps Downloader by Start Menu||All Programs||Google Satellite Maps Downloader
¤¤¤ Define your project properties:
You can view downloaded maps without combining them into one big BMP.
We provide a tool to viewer the images, you can run it from menu "Tools"->"Satellite Images Viewer".
Then open a project from menu "File"->"Open project..." to view the map.
Note: The downloaded images are only for your personal purpose, non-commercial use.
¤¤¤ Start Google Satellite Maps Downloader by Start Menu||All Programs||Google Satellite Maps Downloader
¤¤¤ Define your project properties:
- Project Name
- Left Longitude
- Top Latitude
- Right Longitude
- Bottom Latitude
- Zoom
- Threads count
- Path to save
¤¤¤ There are 4 parameters (Left Longitude, Right Longitude, Top Latitude, Bottom Latitude) to define the area scope of images that you want to download. Thus, I recommend you to define your Area of Interest (AoI) in ArcMap:
¤¤¤ To get Lef-Top and Right-Bottom coordinate (in degrees), you should use Indentify Tool.
¤¤¤ Complete all parameters needed...
¤¤¤ Hit Download button to download. Wait for some minutes to see it finished.
How to view downloaded satellite images?
You can view downloaded maps without combining them into one big BMP.
We provide a tool to viewer the images, you can run it from menu "Tools"->"Satellite Images Viewer".
Then open a project from menu "File"->"Open project..." to view the map.
After downloading, all small images are saved on your disk. Then you can combine them into one big image map. You can run it from menu "Tools"->"Combine images... ".
Now, you get the imagery from Google Earth for the place where you need. I think you should georeference your block image which you just combine. Then you can work with it in ArcMap or any application software.
If you need a quick to georeference your imagery in ArcMap, you would contact me...
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