Let's talk about the Arc video.
This involves some detailed discussion, since the discussion covers the details Esri is glossing over in the video but which in the real world of doing real life georeferencing are the big difference between easy and tedious.
If you watch this videoyou will see how easy it is to georeference a simple jpeg (no coordinate system) in Arc. The impressive thing to me is that it is interactive. In Manifold it is a batch process. With Arc you can see the improvements with each additional control point. In Manifold you don't know whether you've done enough or, perhaps, over done it with control points until you hit the Register button.
The Esri video is a good example of how cramming everything into one window makes it harder. Using two windows, a "from" window and a "to" window (to use Esri's nomenclature), makes it a lot easier. For example:
With Arc you can see the improvements with each additional control point.
Ah, no you can't, because with Arc the "from" thing you're georeferencing hides the "to" thing below. The more control points you add, the harder it is to add them. In the real world, good georeferencing rarely can be done with only three control points. Esri admits that in their video, where they add many more control points and the narrator comments "see how much better that is?" Well, you can't actually see how much better it is because the "from" thing hides what's below.
Esri also skips over the increasingly tedious process of adding control points, where for each one you have to turn the layers off and on so that where you place control points in the upper layer doesn't hide where you need to place control points in the lower layer. That's really clumsy and annoying.
The impressive thing to me is that it is interactive. In Manifold it is a batch process.
In both Arc and Manifold the process is interactive. The key work in georeferencing is placing control points. The ability to do that rapidly and accurately with the fewest motions is golden.
Arc makes that difficult because overlaying the "from" thing on the "to" layer makes the process of adding control points clumsy and tedious. That's precisely why Esri's video skipped over the tedious process of adding seven or eight additional control points. If you had to add 40 control points, as are often required to do a good job of georeferencing historic maps, like the Elliot Map of Gettysburg, you'd go nuts with the Esri approach.
Manifold makes it easy because with two windows, one for the "from" and one for the "to" you can see both layers all the time. You can easily add control points to the "from" layer without having to simultaneously hide that layer, pan / zoom into a view that's better for the "to" layer, and add a control point in the "to" layer.
If you do a lot of real world georeferencing, there are a few things you learn you need for faster and easier workflow. Esri makes those key things harder, while 9 makes them easier:
First, what are convenient views in "from" layers in terms of panning and zooming aren't usually the convenient views in "to" layers. If you have to pan and zoom back and forth from what's best for the "from" layer to what's best for the "to" layer every danged time you add a control point, that very rapidly becomes annoying. That's how it's done in Arc and that becomes really annoying after the first ten or so control points. With 9 you can leave the "to" window zoomed and panned however it is convenient while you choose and mark control points in the "from" window, and vice versa. That's really useful when georeferencing to locations that are view-dependent. For example, several of the control points in the Elliott Map georeferencing project take advantage of locations in the "to" layer that are seen as a result of hill-shaded terrain elevation, such as relics of ruins of walls. Whether those are seen or not seen well depends a lot on the zoom level. You have to zoom out to see they are there, and then you zoom in to the cloud of terrain pixels to place the control point in the middle of what you saw zoomed out.
Second, it usually is faster and more convenient to add all the control points you plan on using in the "from" layer, and then add the equivalent control points in the "to" layer. That's just faster workflow because it allows you to rapidly click, click, click to place control points. You can't do that with Arc, because Arc requires you to do each from-to pair at the same time.
Third, you can do a way more efficient job of picking what you want to use for control points when you can see both "from" and "to" layers at the same time. Then it's immediately obvious what features are distinctive and visible in each, so you can rapidly and with confidence click, click, click on features that are common and good to use for control points. You can't do that with Arc.
Esri's video hides much of that from you by picking an example where the author did the tedious parts ahead of time or where he hid the tedious parts by editing them out of the video. For example, looking at the starting JPEG, how do you know what features in there are also shown distinctively with good detail in the "to" destination? You don't know, because you don't see the "to" destination, but still you have to pick that first point to click in the "from" layer on faith that when you rubber band to the "to" layer you'll find something as distinctive. The author of the video clearly tried that out in advance, so he knew to click the point of land extending out into the water.
But if you try that in real life you'll see it's incredibly annoying and tedious to try to choose sensible control points to click in the "from" layer without knowing whether there will be equivalent control point locations in the "to" layer. And knowing what will work in advance is part of doing interactive georeferencing quickly, easily and with high quality.
A good example is the Elliott Map of Gettysburg that's used as an example in the Manifold web site. That's a real-world example using around 50 points that's easy to do in Manifold but which take many times longer in Arc and would have you tearing your hair out in frustration at the inconvenience of how Arc does it. The inconvenience comes from having to do everything in one window: you can't see what control points do because the "from" layer hides the "to" reference, and not being able to see both "from" and "to" layers in two different windows at the same time makes it far, far harder to pick candidate control points.
In the case of the Elliott Map that latter bit is the key to successful georeferencing: if you can simultaneously see the "from" Elliott Map scan and the "to" target layers, you can quickly pick out features in common, such as houses shown on the Elliott Map that still exist and are visible in aerial photos. But if you can't see both at the same time, it's way too hit and miss to try to find equivalent locations, and for the ones you can find it's too hard to pick from them which are better quality than others.
With Arc you can see the improvements with each additional control point. In Manifold you don't know whether you've done enough or, perhaps, over done it with control points until you hit the Register button.
Not so. You can see that in the Manifold georeferencing videos, where you interactively can see what the control points do by clicking Preview. You don't have to hit the Register button.
In Manifold you click the Preview button and you get a great view of how the control points you've set up will work, and that Preview is much better than what you get with Arc, because with Arc you cannot see the improvements with each additional control point, since the "from" thing hides the "to" reference below it. Manifold previews don't hide what's below since you can use partial opacity and you can use the slider interactively to compare the georeferenced preview to the reference layer. You can also change the georeferencing algorithm (affine, etc) to see what that does. It's a far more effective interactive user interface if you want to see how additional control points or georeferencing methods change things.
It's also a plus to click Preview to see a Preview, because you don't want to make the mistake Esri does of covering your work with control points in the "to" layer all the time.
If you want to make an apples to apples comparison, choose an Esri video that shows the entire process. The video cited doesn't do that. Instead, it skips over real-world details that make it harder:
* It skips the setup of the initial JPEG. If you bring in a JPEG that genuinely has no coordinate system it often ends up off the African coast in the 0,0 location. Here, they've picked an example using MD state plane where it ends up on land and not too far from where you can pan the underlying map to a first "to" location easily. They also choose an example where there's a named feature they can pan and zoom to without the hair-tearing frustration of finding something equivalent that isn't in the lookup database, like you usually have to do with georeferencing of drone photos. That's a big cheat.
* It skips the examination of the proposed "to" layer to pick out a viable control point to start the process, so that when you first click in the "from" layer you know that you've clicked on something that's also distinct in the "to" layer.
* It also skips the review of the "to" layer for the subsequent control points, to know what's visible in the "from" layer is also distinct in the "to" layer. For example, the author knew in advance the road intersection he chose in the "from" layer isn't covered by cloud or trees or is otherwise poorly visible in the "to" layer.
* It skips the tedium of adding seven or eight more control points, that part being edited out of the video to just show the situation after they've been placed. In real life, the back and forth of turning layers off and on and so on for each control point pair while you're in the middle of clicking it gets really annoying.
Unfortunately, Esri does not provide the source data they used so that somebody can independently do a full version of the video that showed all the steps you'd do in real life as they have to be done. If you did that video, and then also did an equivalent video in 9, you'd see how it's much easier in 9.
If anybody wants to contribute links to the data Esri used, that would be a fun video to do to compare.
Ah, and last but not least, where's the video that shows the georeferencing process to be used if instead of georeferencing a JPEG you'd georeference a shapefile that's in an unknown coordinate system? How about georeferencing a JPEG or a shapefile to a vector layer? Those are different processes, which require you to learn a different way depending on what you're using for "from" and "to" layers.