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Opening .tiff geoimages consumes enormous memory

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  • J Offline
    J Offline
    john_hobbyist
    wrote on last edited by john_hobbyist
    #3

    But the .tiff is compressed, isn't it?

    I execute this code to open the .tiff

    code.py

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    • gde23G Offline
      gde23G Offline
      gde23
      wrote on last edited by
      #4

      You're right. Didn't think about that.
      What size (in pixels) does the image have and what datatype do you load it to?
      Then you can easily calculate what size (in memory) it should have as a openCV mat object and if the image should fit into your PCs memory.

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      • J Offline
        J Offline
        john_hobbyist
        wrote on last edited by john_hobbyist
        #5

        5000 x 7000 pixels. I use opencv.

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        • mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by mrjj
          #6

          Hi
          A 500 MB tiff is massive if high compression is used.
          Unless you have 32+ GB ram, it might not be possible to open it.

          The alternative is to load it in chunks
          https://wiki.qt.io/Loading_Large_Images

          But depending on what you need to do with it, it might not be a solution.
          Also I have not tested this with the TIFF format.

          Ah, never mind. you want use openCV to load the image.

          update:
          You might want to check out
          https://github.com/pearu/pylibtiff
          it's a python wrapper for libtiff which is supports tiles (chunks) directly.
          So you might be able to load it via this and us openCV to display.
          https://answers.opencv.org/question/86621/reading-geo-tiff/#86740

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          3
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #7

            Hi,

            One thing to take into account: to represent a compressed image in a format like RGB, you will have to decompress it. You are mixing storage and usage. Depending on what you need from that image, you may have a thumbnail already embedded into it. In any case, you really should analyse what you need to do with that image and then adapt your code for that. Like suggested by my fellows there are tools to deal with these kind of data.

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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            • J Offline
              J Offline
              john_hobbyist
              wrote on last edited by john_hobbyist
              #8

              I am trying opening the tiff with this command:

              QImageReader reader("/home/UbuntuUser/Desktop/UAV.tif");
              print(reader)
              

              but something is wrong... Any idea?

              update:

              File "code.py", line 547
                  QImageReader reader("/home/UbuntuUser/Desktop/UAV.tif");
                               ^
              SyntaxError: invalid syntax
              
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              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #9

                What does "but something is wrong" mean ?

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                2
                • mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #10

                  Hi
                  That looks like c++ syntax but you are using python, right ?
                  So is it not like
                  r = QImageReader("/home/UbuntuUser/Desktop/UAV.tif")

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                  • J Offline
                    J Offline
                    john_hobbyist
                    wrote on last edited by john_hobbyist
                    #11
                    This post is deleted!
                    mrjjM 1 Reply Last reply
                    0
                    • J john_hobbyist

                      This post is deleted!

                      mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by
                      #12

                      @john_hobbyist

                      Hi
                      Why this old version ?

                      Anyway, what are you trying ?

                      Building PyQT4 from source ?

                      Also is there any reason you want to use the competing Qt binding from another company instead of the
                      official support one called pyside2 ?
                      https://pypi.org/project/PySide2/
                      https://doc.qt.io/qtforpython/

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                      2
                      • J Offline
                        J Offline
                        john_hobbyist
                        wrote on last edited by john_hobbyist
                        #13

                        @mrjj

                        I don't know what goes wrong...

                        I just try to handle large tiff images instead of using opencv (that makes my program realy slow) with QTimagereader

                        Sorry, I didn't identify it was a competing company...just a result in google when tried to install PyQt4

                        Ok, I will look at it.

                        mrjjM 1 Reply Last reply
                        0
                        • J john_hobbyist

                          @mrjj

                          I don't know what goes wrong...

                          I just try to handle large tiff images instead of using opencv (that makes my program realy slow) with QTimagereader

                          Sorry, I didn't identify it was a competing company...just a result in google when tried to install PyQt4

                          Ok, I will look at it.

                          mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by mrjj
                          #14

                          @john_hobbyist
                          Hi
                          Np I just wondered why you want Qt4 version and build from the source when
                          PyQt5 is there and seems to be installable directly.
                          Also here is how to use it
                          https://programtalk.com/python-examples/PyQt5.Qt.QImageReader/
                          Do note none of them use setClipRect to load image in chunks but
                          should be easy to add.

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                          1
                          • Christian EhrlicherC Offline
                            Christian EhrlicherC Offline
                            Christian Ehrlicher
                            Lifetime Qt Champion
                            wrote on last edited by
                            #15

                            QtImagrReader is for sure not the correct way to handle geotiff. Either use openCV or better gdal for such tasks.

                            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                            Visit the Qt Academy at https://academy.qt.io/catalog

                            J 1 Reply Last reply
                            2
                            • Christian EhrlicherC Christian Ehrlicher

                              QtImagrReader is for sure not the correct way to handle geotiff. Either use openCV or better gdal for such tasks.

                              J Offline
                              J Offline
                              john_hobbyist
                              wrote on last edited by
                              #16

                              @Christian-Ehrlicher

                              I am trying GDAL in order to print the image:

                              from osgeo import gdal
                              import sys
                              
                              ds = gdal.Open('UAV_image.tif')
                              print(ds)
                              

                              and I get this error:

                              <osgeo.gdal.Dataset; proxy of <Swig Object of type 'GDALDatasetShadow *' at 0x7fb89062b840> >
                              

                              Any idea what I am missing here?

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                              • Christian EhrlicherC Offline
                                Christian EhrlicherC Offline
                                Christian Ehrlicher
                                Lifetime Qt Champion
                                wrote on last edited by
                                #17

                                @john_hobbyist said in Opening .tiff geoimages consumes enormous memory:

                                Any idea what I am missing here?

                                Nothing. All is fine.

                                Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                Visit the Qt Academy at https://academy.qt.io/catalog

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                                • J Offline
                                  J Offline
                                  john_hobbyist
                                  wrote on last edited by
                                  #18

                                  Why I cannot see the image?

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                                  0
                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #19

                                    The Python print function only print strings or a string representation of the object.

                                    Check if GDAL provides a widget or equivalent for that.

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                    2
                                    • J Offline
                                      J Offline
                                      john_hobbyist
                                      wrote on last edited by john_hobbyist
                                      #20

                                      Ok, until now OpenCV requires ~24GB RAM, gdal does not work. Is there any QImageReader sample code to open the .tif? I am searching the google for this...nothing found.

                                      mrjjM Christian EhrlicherC 2 Replies Last reply
                                      0
                                      • J john_hobbyist

                                        Ok, until now OpenCV requires ~24GB RAM, gdal does not work. Is there any QImageReader sample code to open the .tif? I am searching the google for this...nothing found.

                                        mrjjM Offline
                                        mrjjM Offline
                                        mrjj
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #21

                                        @john_hobbyist
                                        Hi
                                        in what way did GDAL not work ?

                                        Also, Mr @Christian-Ehrlicher made me realize that geotiff is a special tiff so
                                        even QImageReader can read an image in sections. it might not really do what you want.

                                        What do you need to do to this image ?

                                        1 Reply Last reply
                                        1
                                        • J john_hobbyist

                                          Ok, until now OpenCV requires ~24GB RAM, gdal does not work. Is there any QImageReader sample code to open the .tif? I am searching the google for this...nothing found.

                                          Christian EhrlicherC Offline
                                          Christian EhrlicherC Offline
                                          Christian Ehrlicher
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #22

                                          @john_hobbyist I wonder what you want to do with this image when you even don't know the basics of this format... it's a georeferenced image with multiple images and bands inside. It's not a simple picture at all.

                                          Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                          Visit the Qt Academy at https://academy.qt.io/catalog

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