07-10-2018 04:00 PM
I do have a question and I would like to change the dimensions of my two TIF files. They are both large width and height...they have no projection.
Is there a way for me to change that ?
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07-10-2018 08:35 AM
Could you please elaborate on what you mean by "change the dimension"? Do you want to subset a section of the image? Do you want to rescale / resample / downsample to a different pixel size? Etc.
07-10-2018 09:26 AM
Thank you, Ian.
I am sorry I could not provide in more detail.
What I want to change the dimension in Width and Height. My historical aerial photos was scanned by a contractor and came in with the external hard drive that has all the historical hard drive..
There are couple that I wanted to change the dimension is because a few of them has large dimension and some of them have smaller dimension...
For example, one of my aerial photos I have shown me in Layer info: Width 13398 Height : 16759.
The map info(Pixel Center) shows here
But I am not sure if I could change the dimension here ?
07-10-2018 10:04 AM
Interesting. So your data provider scanned the images and tagged the TIFFs with the micron scanning pixel size. Which is technically correct, but doesn't really help from a geospatial perspective.
But you can work with it. I'm assuming from what you're saying that you want a smaller image dimension (fewer rows and columns) but retaining the whole image extent? I.e. down sampling the pixels. Is so, one of the simplest things would be to use the Raster tab > Resolution group > Spatial menu > Resample Pixel Size option. Select your "big" images as input and then specify the output pixel size you want. So if you wanted one with half the rows / columns and the input pixel size is 0.0014 cm, you could specify a desired pixel size of 0.0028 cm.
You can Batch this process if you want to apply it to multiple images.
You can also set the output file format to TIFF, but if you want them to be JPEG encoded still make sure you first set your TIFF preferences to achieve that (the default is uncompressed if I recall).
Hope this help.