Satellite Image Processing

Dear all,
I am a new KNIME user.
I would like to use the platform for processing satellite images, but I have encountered difficulties therefore I looking for your help.
I imported two spectral bands of the LANDAST ETM + image using the Image Reader node, I calculated the NDVI with Image Calculator and I exported the result obtained by using Image Writer node.
The resulting image, however, is not geo-referenced. Why I lost the reference system during the workflow? How I can fix this problem ?
Thanks in advance.

Hello @Maggy,

Apologies for the delay on getting a response. Could you possibly share the workflow that you are running? It sounds like everything is working as expected until the Image Writer.

When you mention Geo-referenced what exactly are you expecting as an output?

Regards,
Ryan

Hi Ryan,

Thanks for your availability.

The desired output is an image (in this case the NDVI) in GeoTIFF format, incorporating geographical references in the image.

The B3 and B4 bands of the examined satellite image are geo-referenced (EPSG: 32633 - WGS 84 / UTM zone 33N), instead the output obtained from the processing of the two bands has an unknown reference system (I imported the output in the QGIS platform) and this does not allow me to overlap images (input and output) for subsequent processing.

Attached is my workflow.

Satellite Image.knwf (22.4 KB)

Hey Maggy,

I took a look and don’t have the actual image files to see how the output progresses through the flow. What I can say is that there is no image / pixel processing available only vector data.

I hope this helps,
Ryan

Hi Ryan
Excuse me.
I am sending you a sharing link to the folder containing satellite images (B3 e B4).

Satellite Images (B3 and B4)
Thanks,
Maggy

Hey @Maggy,

I would be curious to know when the images are losing the geo-reference, is it directly after the image calculator?

Also please ignore my previous comment, that is not necessarily true.

Regards,
Ryan

@Maggy,

Just found out that all metadata on the image gets lost when loaded in. The reason being is that with images often attached metadata is not standardized so from KNIMEs perspective it would be difficult to maintain / update the product, which is why this gets discarded. An exception to this is EXIF image data in JPEGs which is a much more reliable standardized piece of metadata.

Apologies for the delays on the responses and I wish I had better news or a solution to give.

Regards,
Ryan

Hey @rsrudd

Thanks for your availability.
If I could to find a solution I will update you.

Best regards,
Maggy