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I'm beginner of ARCGIS and RS. I have many problems with the procedure. One of them is
I have NDVI images and Soil map. Both are at the different resolution: NDVI is 250 m. soil map is 1000 m. So I wanna ask how can I change the resolution from 1000 m to 250 m.

Thanks a lot

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3  
If you intend to do any combined analysis with these layers, the worst resolution is going to be the highest level of detail that you'll be able to correctly have any confidence in. That being said, you'll also save 3x the time by reducing the resolution of the 250m dataset to 1000m and then proceeding. –  Jim B May 25 '11 at 18:28
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@Jim Good points. The 3x actually varies according to the grid's storage format and the complexity of the processes that will be applied to it, but overall a better estimate is 15x: the 1000m grid has only 1/16th as many cells as the 250m grid. –  whuber May 25 '11 at 18:43
    
Oh right... the second dimension... :) –  Jim B May 25 '11 at 20:39

3 Answers 3

The operative word is Resample, the version link is provided, similar links exist for prior versions of Arcmap. Also be aware of resampling issues associated with the resampling method and the nature of the data being assessed.

EDIT If you want to go the reverse route (ie decrease resolution) see Aggregate or Resample but be careful to choose your options based upon your input data type.

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I would like to add Block Statistics as another method to alter the resolution of a raster. Depending upon your specific goals, Block Statistics allows fine control of how pixels are assigned based on:

  • A user defined neighborhood (e.g. rectangle, circle, wedge etc)
  • The type of statistics calculated within each block (e.g. mean, majority, variety etc).

In this example, pixel values are assigned based on a 3 X 3 rectangular window using "maximum" statistics.

enter image description here

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Import image, define projection and export with lower resolution.

  1. Open an empty Project in ArcGis.

    a. Click on the following icon:
    enter image description here

  2. Define datum.

    a. Click with mouse right button at the word “Layers”:
    enter image description here

    b. Select “Properties”.
    enter image description here

    c. Go to the field “Select a Coordinate System” and choose as from option list, the desired geographic coordinate system and datum to be applied to data. Click “Ok”.
    enter image description here

  3. Open an image of interest.

    a. Click on the following icon:
    enter image description here

    b. Choose file which correspond the image of interest and click “Add”.
    enter image description here

  4. Export the image at lower resolution.

    a. Click with mouse right button on the image to be exported, select “Data”, and then, select “Export data”.
    enter image description here

    b. Define the new pixel resolution:enter image description here
    Remark: always keep equal pixel dimensions (example given; go through 250 m x 250 m to 1000 x 1000 m.

    c. Define local, name and extension type of the file that will be created.
    enter image description here

    d. Check if image’s properties are in agreement with what was expected.
    enter image description here

    e. Click on “Save”.

    Any revision/edition toward improvements will be gladly accepted.

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It seems that in this way, you do not have any control over algorithm behind it. Though it will change the resolution. –  Tomek Apr 3 '13 at 11:36
    
@Tomek. It's work for me when I need to open images in software less powerful (i.e. do not handle with high resolution images) than ArcGis. Thought it would be a good information, once it is very fast to do it. –  Andre Silva Apr 3 '13 at 11:50

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