Master Image

[Reginald Hanfy]

LogicallyI would have thought, I use the image before the flood as the first input (master) and the image after the flood as second input (slave).

After I computed everything I need for the measurement of displacements (Read -> Apply Orbit File -> Back-Geocoding -> Interferogram -> TOPSAR Deburst -> TopoPhaseRemoval -> 2x Goldstein-Filtering -> SNAPHU Export -> all the stuff in SNAPHU -> SNAPHU Import -> Phase to displacement) I get quite a nice picture with everything I wanted, except that when I compared it to an orthophotograph, my displacements were just the exact contrary of what really happend (like when there had been any uplift, my displacement map would show a subsidence and vice versa.)

SNAP shows the information relative to your master image. So an Image was taken after an event should be your master image, and an image was taken before the event should be your slave.

Or maybe, it would be also possible to multiply your result image on the -1 in the Raster->Band Math.

am somehow confused with this answer. is it always the case or it is a special case for this situation, because from my knowledge the master should be the image before and the slave the image after. just like @Mia i dit same and on comming out the master image was choosen to be the one after the event so its somehow confusing because from this same forum it is said the master should be the image before. please more light if possible.

Good evening,

I have analyzed the interferometry of 5 groups of 2 S1A_SLC_IW images

(2 January_14january/14_January_26January/26January_7February/7 February_19February/19february_3 March).

I have done all the steps and at the end I have calculated the vertical displacement for each of them.

In order to have a feedback, I have done the same steps using the first and the last image used in the previous groups (2 January_3March).

I thought that I would have had in the same pixel the sum of the values obtained for each previous analysys but it it did not go that way.

I have used for each analysys the first image like master and the second like slave.

I have read your post and I have read that I should do it in reverse.

Please tell me if I have to consider each first image like slave and second image like master and why?

Please can you help me and tell me why my calculate are wrong?

Thanks.

Have a nice evening and please give me a feedback

theoretically, the sum of the short pairs should equal the total displacement between the first and the last image. But there are many error sources which distort both measurements. Have a look at these slides: _errors

It is happening a very strange things.

I have analyzed two time the same 2 images and I have done the identical steps.

The two results have different values.

If I consider the same pixels the displacement values are different.

How can it is possibile?

Please help me,

Thanks.

Thank you for your answer but I can not understand.

If I take the same images and do the same processing, how is it possible that the result is different?

So based on when I do the processing, does the result change?

This way the result is not reliable.

In addition, the values obtained by me are not slightly different but very different (the sign also changes).

Considering two equal pixels, the results are as follows:

The only thing I can think is that pixels do not correspond exactly to the same point, so there can be a difference.

But anyway it seems very strange that it is so substantial.

It seems too strange because I did the same identical steps using the exact same images.

Can you please clarify this concept?

Thank you.

InSAR measurements are relative so only differences like (pixel 1 - pixel 2) have a meaning. And if unwrapping starts at a random location that can explain the rest. Unwrapping is a messy and imperfect process on noisy interferograms with layover and shadows for example.

ok but the difference between two pixel corresponds at a geolocation.

so if I obtaine a different differencebetween the same two pixels using the same images and the same process, it is a problem.

How can I solve the problem and obtain the same result?

Good morning,

nobody can help me about the starting pixel of Snaphu?

Furthermore I need your help about another question:

I have done a subset of an image using the coordinates of a city (N,S,E,W) and at the end I have exported the final result on google earth (.kmz).

I have noted that there is an error about the coordinates, infact I have not the full city but only a part.

I have repeated the operations more times but the problem is the same.

Somebody can help me please?

Thanks.

best regards.

Good morning,

nobody can help me about the starting pixel of Snaphu in order to havethe same results in different processing of the same images and about the coordinates that do not corrspond at he real cordinates?

Please help me.

Best regards.

To be honest, I disagree with Spielberg on this. I think this is one of a handful of images that are absolutely key to his film-making (the Moon shot in ET: The Extra-Terrestrial is an obvious one, along with the shot of Francois Truffaut signing to the aliens at the end of CE3K), but you can see why he holds this in such high regard.

One workaround you could use is to hide and/or cover the image widget that is placed in the master with an image widget that is placed directly on the page. In this way, you would not have to break away the entire master or modify the current images overrides, but you would be able to more easily control the visible images.

Am I right in thinking this needs to be done every single time an image is updated? Presumably if I fire up an image just to do a simple take like updating Chrome, the MCS service will start and re-create all the settings that were cleared.

In case you are using Non-persistence VDI - Yes, the above mentioned KBA needs to be followed if the MCS services are in the started state. However, you may try having the MCS services in the disabled state while making the required changes and then set services in stop state once you are done. This way once you fire up the image again it will automatically start the MCS services. This is something that is not officially documented but logically should work.

I tried setting the service to disabled and then using a script to set it back to auto on first boot but that hasn't worked. Looks like tamper prevention is preventing the script from changing the service start type.

What i want to know is if its possible to configure one of these machines to our specification as a master and then create an image/clone of it to roll out to the rest of them. They will all come Licensed with Windows 10 Pro i assume OEM.

It is possible that the OEM license is burnt into the BIOS of each computer.But if it is not, doing the activation will avoid 30 computers trying touse the same license and getting it black-listed by Microsoft.

Using sysprep requires some knowledge and mistakes are possible(see issues on our site).Cloning is just a matter of pressing the button, no learning curve at all.Many companies use cloned hard disk as the simplest solution,even using specialized cloning devices for mass production.When the OEM license is burnt into the BIOS, this is by far the simplestsolution.

Depending on what exactly you're needing to customize, you may be able to avoid all of the licensing problems by using a setup script instead of re-imaging the systems. Systems of the same model coming from a manufacturer will all come with the same image on them. Create a PowerShell script or write a short program that modifies a system to meet your requirements (install/remove software, modify registry, configure system settings, etc etc). Your systems would start in the same state and run the same script, so they should end up in the same state. But, by avoiding imaging, you've also avoided the headache that is Windows licensing.

When creating a master image for Windows or Linux, you may include an agent installation. However, there are files and registry settings that you must set per host. By removing and changing files, the agent generates new files once the agent reboots. If the host is imaged with these files and you attempt to link several imaged agents, you receive a 409 UUID error.

Note: Do not restart the agent service on the host until you have taken the image. Restarting the agent service regenerates the UUIDs, tags, and files that the prepare-image command has purged.

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I am updating my documentation on master image creation. Just wondering

what others are doing to customize their master image. Such as:

Turning of external accounts,

Setting time machine to not offer new disks for backup

Deleting networkinterfaces plist

I am currently on hold on my cell phone calling a utilities company so I am very bored and can't do anything. I am also not in my office so I don't have my complete list of notes on my image handy but I can give you a rough draft of what I do to create a master image.

If we're talking about a base OS image, I do very little...

1. Perform OS custom install with all selectable options turned off.

2. Run latest Mac OS Combo updater

3. Go through Setup Assistant, create primary IT admin account.

4. Turn on SSH (Remote Login) and ARD (both for admin account only).

5. Change machine name to "unmanagedclient"

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