Satellite images in ArcMap - An Introduction 

Landsat data provided by the USGS has a Level 1 correction already applied - you can read more about it here: landsat.usgs.gov/landsat8.php - there is a link on that page to the User's Handbook that has more detailed information. I hope that helps.

Thank you! 😃

Sorry for the late reply - for some reason I didn't see your comment until now. It's hard to tell what might be happening. If your image looks red, then that's likely because you're assigning the red on your monitor to a band that has high values. For example, if you assign the near infrared band to appear as red on your display, then vegetation will appear red as it has high values in that band. For an NDVI, the values will have maximum range of -1 to +1, but how they appear will depend on the color scheme you apply.

You're welcome! An image rectification video is a good idea. I'm afraid I won't have time to do it anytime soon though - but it's on my to do list!

Building pyramids is just a trick the software uses to display the image more quickly as you zoom in and out. It doesn't change the actual image data. You can read about them here: desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/raster-pyramids.htm

Sorry, but I don't have much background in geology, so can't really help you.

+em sreang sorry I just have the introductory ones - I'm sure there are others on RU-vid though

Ok, professor. thanks

Glad you think so!

I'm not sure what you mean by not clear - perhaps it needs to be enhanced, as most imagery is fairly dark by default

Yes, that could certainly work - for example if you have before and after images.

thanks, i need to check the deforestation of my research area about how much deforestation took placed during the last 20 years and make a pictorial graph of last 20 years.

You're welcome!

+Sonu Hansda great - glad it was helpful

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ArcGIS supports many different file formats - you can find a list of them here, including a column that indicates whether compression is supported: desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/supported-raster-dataset-file-formats.htm

Thank you, but I want to compress a multi band raster image in arc gis or Erdas imagine, May u explained the process? Please

If you store the data in an Erdas .img file I believe it is compressed automatically. According to this page desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/raster-compression.htm , this also happens when you store raster data in a geodatabase "ArcGIS can store compressed data in the following formats: IMG, JPEG, JPEG 2000, TIFF, Esri Grid, or in a geodatabase. When storing data in the geodatabase, the blocks of data are compressed before they are stored." - I have to admit I don't normally think about it much, as I just let the software compress as needed.

No, it's not working. I had already seen ds but unsuccessful. Please make a video of raster image compress

ok thanks for your job to me, but what about erdas?

Hi Charles - sorry, but I'm afraid I'm not able to devote the necessary time to walk you through it. However, this page has the instructions I think you need: support.esri.com/en/technical-article/000012441

Thank you very much for your quick response, i will look at it and see how it will help my work. thanks again

Sorry it wasn't what you were looking for. Perhaps this video will help you: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1ytgbKs93Kk.html