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I have to show scale in my reports, so I need to know. Please bother to tell me.

RAJEEV SHYAMAL GHOSH
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  • Just as LISS4 produces images at 1:250000 scale, so on which scale does Sanitel record the image.In the metadata of sanitel, it is given about the volume but not about the scale. So I have to know the scale of sanitel data. – RAJEEV SHYAMAL GHOSH Sep 25 '19 at 11:03

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The scale is related to the map and not to the source data set (image or vector). Of course, it doesnt make sense to show an image on a map if its resolution is not appropriate, but it is always "technically" feasible.

The smallest pixel size of Sentinel-2 is 10 m (for bands 2,3,4 and 8, aka blue, green, red and NIR). So the maximum scale to use it without seeing the pixels is about 1/50000 (considering that the resolution of your eye is approximately 0.2 mm). On the other hand, the swath width of Sentinel-2 is 290 km, so showing a full scene on a A4 page would be approximately 1/1500000.

In practice, most GIS softwares will compute a scale on the fly when you zoom in and out on your image, because it is georeferenced. If you are not using a GIS software, you need to compute the scale by yourself (based on the ratio between the extent shown and the size of the map along X or Y dimensions)

radouxju
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  • According to you, Sanitel captures images at a scale of 1: 500000. – RAJEEV SHYAMAL GHOSH Sep 25 '19 at 11:04
  • No, I did not say that. First, I mentioned 1/50 000 as a scale at which you don't see pixels (approximately, it depends on your vision), and not 1/500 000 . Second, you can show the image at different scale and still use Sentinel-2 data at smaller or larger scale; – radouxju Sep 25 '19 at 14:42
  • I know that we can give scale according to ourselves. But each satellite has a scale according to which it captures the image. I am grateful for your reply. – RAJEEV SHYAMAL GHOSH Sep 27 '19 at 05:32