A Semantic Issue

[ccpandhare]

How addSteps, removeSteps, etc. work currently :
If no image is specified in the addSteps or removeSteps arguments, then the operation is performed on all images.

Recently we allowed chaining of methods which enables us to do this:

    sequencer.loadImage('image.jpg').addSteps('ndvi-red').run()

As you can see, no image is specified with addSteps. This means that ndvi-red will be added to ALL images present in the sequencer.

What should be done:

• If chained, apply the steps only to the image which is being chained by storing which steps are being chained and the image associated in the object returned by these methods?

or

• Force the user to specify the image.

[jywarren]

I guess I think a diagram would be useful here, showing images, their movement through the steps, etc. I was tempted to say we should just create a separate instance of sequencer for each image... but that doesn't make a lot of sense. Not only is it useful to be able to "cache" any image that's passed through, so we can efficiently rerun things, but if we want to load a new image in, it makes some sense that it wouldn't "flush out" preciously run images. But then, as we load in images, will memory use go up enormously? What if we try to run this on 1000 images as a batch process? What if we don't cache by default, and we don't store per step image state unless specifically set in an options flag like cache: true? I'm not sure yet, but these are the use cases to consider. What do you think? J

…

On Jul 8, 2017 9:26 AM, "Chinmay Pandhare" ***@***.***> wrote: How addSteps, removeSteps, etc. work currently : If no image is specified in the addSteps or removeSteps arguments, then the operation is performed on all images. Recently we allowed chaining of methods which enables us to do this: sequencer.loadImage('image.jpg').addSteps('ndvi-red').run() As you can see, no image is specified with addSteps. This means that ndvi-red will be added to ALL images present in the sequencer. What should be done: - If chained, apply the steps only to the image which is being chained by storing which steps are being chained and the image associated in the object returned by these methods? or - Force the user to specify the image. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#48>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABfJ9OIWFOL3A8ugCdPJHbfevveaX2Vks5sL4OHgaJpZM4ORvRK> .

[ccpandhare]

I think you are right. We should cache the state only if it is required.

Also I have created a pull request which solves the issue I have mentioned above #53