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Hi James, Thank you for providing that detail. Yes, that is interesting. Perhaps we can connect directly to discuss your needs specifically. Let me know if you need any help obtaining an evaluation license for the image analyst extension. Thanks again, Dan
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04-29-2020
08:57 AM
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Hi James, The behavior you are seeing is incorrect. In map space, the image (X, Y) coordinates displayed in the Image Information Pane should absolutely correlate to the pixel location of the underlying image. In fact, the coordinates next to the image (x, y), should display the accurate pixel location of the cursor, or point of interest, regardless of working in map space or image space. However, you are running into a bug which is interfering with correctly reporting image (X, Y) coordinates in the Image Information Pane when working in map space (i.e. Projected or Geographic). We are working on enhancements and bug fixes to the underlying image coordinate system (ICS) that will address this issue so that the coordinates are correctly displayed in the Image Information Pane. Also of note is the status bar at the bottom of a map view. When working in image space, the image coordinates are displayed in parentheses next to the ground coordinates. If you don't mind, can you verify that the image (X, Y) coordinates are correlating correctly to the underlying image when working in image space? Also, would mind sharing any details on the type of image you are working with? Is the image a satellite image or an airborne image? What image format are you working with? Thank you, Dan
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04-28-2020
03:16 PM
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It looks like that the stretch renderer was applied. If you access the image layer properties from the ToC can you manually change the renderer in the display from Stretched to RGB Composite?
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07-30-2015
10:34 AM
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Regarding pixel depth, this is not the same as spectral value/digital number, in fact signature is different too. Pixel depth is a data type definition for a raster, it is representative of each pixel in the raster. Another way to think about it would be that it is the possible range of values for a given pixel. Hence 8 bit raster can store up to 256 values per pixel (0 - 255). A 16bit raster can store up to 65536 values for a given pixel (0 - 65535). So in a remotely sensed context, an image that was captured using a sensor that was sensitive enough to "see" enough differences in a location on the earth (say a 1m x 1m spatial resolution) to occupy a 16bit range would have much higher radiometric resolution than a sensor that could only detect an 8 bit range. This is per spectral band. A signature is a little different. A signature in this case is another way of talking about a spectral response curve for a give location across all spectral bands. Light is absorbed/reflected off of a leaf differently across different parts of the em spectrum (i.e. bands). Some materials have characteristic spectral response curves, so the pattern of their 2D plots are recognizable, and so people have used the term "signature" to refer to this. As for signed vs. unsigned. In a practical sense, I've only seen this when a describing depth/elevation. If you have terrain that is below sea level (e.g. some areas in death valley, Ca) and you have a raster that represents elevation, you may use negative and positive values to describe below and above sea level).
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07-29-2015
05:10 AM
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Just a small point of clarification, not all rasters have a spectral resolution, since not all rasters are technically measuring the EM spectrum with sensors tuned to a specific set of wavelengths. Some raster's pixel data represent categorical data, such as land cover classes, soil types, forest types, elevation classes, slope, aspect, or may even be derived from scanning a paper map. Given that I thought it was worth making this distinction. It might better be said that, "A remotely sensed image has...." .
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07-29-2015
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