Stephen Ervin of Harvard University delivers a fascinating presentation about object-oriented diagrams in GeoDesign at the 2010 GeoDesign Summit.
00:01 So, I want to be, not contrarian, about terminology, but offer refinement.
00:08 And I want to talk about diagrams because I think they're really, really interesting.
00:15 And essential to our enterprise.
00:17 And they're like maps, and they're like sketches, both words that we've been tossing around quite a lot lately.
00:24 But they're unique.
00:27 I think most of us can call that a sketch.
00:30 It had characteristics of having been made quickly.
00:32 It has characteristics of representing some real-world attributes like texture sometimes, or color, or outline, et cetera.
00:43 Many of you will recognize that as a map.
00:46 It also has some relationship to some real-world stuff.
00:50 Either shape or scale, but not both.
00:55 And other kinds of abstractions to be sure, but kind of one-to-one mappings.
01:00 That's one reason we call it the map to the world.
01:04 And then there are these critters called diagrams, which are graphic things.
01:10 And they talk about, or represent, or abstract, real-world and spatial things, but in a different way.
01:19 And in critically different ways.
01:23 Diagrams graphically represent high levels of abstraction, just as maps do...
01:28 ...and perhaps in a different way that sketches and photographs do.
01:34 They emphasize critically elements and relations, a good basic database concept, such as topology, for example.
01:47 Duality, singularity, and other kinds of high-level topological constructions...
01:53 ...rather than, for example, measurement or detail that you would find often in a map or a sketch.
02:01 And they're often used in the process of explanation or argument...
02:05 ...whether with yourself or your client, your instructor, your students, your colleagues.
02:12 There are many kinds of familiar diagrams in different disciplines.
02:17 They all have the characteristics I talked about, having elements and relations in them.
02:22 They use color.
02:24 They often use arrows for various reasons.
02:28 They are...even though they may...some of them are more maplike than others.
02:33 They're not maps in ways that we can distinguish them, and to be sure, there are...
02:38 ...this is a continuum, and there are sketchlike maps, and there are maplike diagrams.
02:41 And there are things that are odd hybrids that we can't quite figure out until we see how they're being used.
02:46 And that's an important part of the thing here.
02:50 Here's a famous one. Garden Cities of the Future, Ebenezer Howard.
02:56 This is a fragment of a larger diagram, and he says, "Note: This is only a diagram."
03:03 We can't make the plan; we can't make the map...
03:06 ...and I'll use those two terms interchangeably for now...
03:08 ...until we have a site.
03:10 So there's something different here.
03:12 This is a set of concepts, ideas, elements, and relations that have yet to land on the ground.
03:20 And when they do land on the ground...
03:22 ...then they will generate maps and plans and work orders and construction equipment and all that kind of stuff.
03:29 And here's a canonical, familiar bubble diagram from the architectural and land planning enterprise...
03:36 ...where once again, we see elements and relations and topological constraints like connectedness and maybe family relationships...
03:46 ...where color is used to designate there's something the same about these, but we don't know what it is, perhaps, even.
03:52 Or maybe we can begin, it's so obvious what it is.
03:54 And there's a very simple graphical palette that's constrained by all those semiotic rules...
03:59 ...that Bertrand and others have helped us understand the uses of...
04:03 ...that are used to map these concepts, not their terrain-based implementation.
04:11 But what's so cool, I think, and interesting, and fabulous, and important, about these...
04:16 ...is that in fact they have this...some kind of a relationship to maps.
04:21 They can be derived from maps.
04:23 We can look at a map or a plan and diagram it.
04:26 Or, we can take a diagram and instantiate it as a map or a plan.
04:32 And so they hold this interesting...
04:36 ...dare I say, epistemological relationship to what we know and how we know it, and where it lands...
04:42 ...in the birth of maps and plans, and the design process.
04:48 And Carl showed us multiple examples of diagrams in his talk this morning.
04:49 So, to reiterate, diagrams embody concepts, or ideas, like inside and outside and edge and large and many.
05:01 And if you go back and listen to the video of his tape...
05:04 ...you'll see he talked about diagrams and he said that designs are different 'cause they have different diagrams.
05:10 I collected these diagrams and we combined them.
05:13 And I kind of knew what he was going to talk about, but I didn't actually set him up to say all that.
05:19 Ideas can be implemented and manifested in diagrams, and diagrams can generate maps.
05:26 And you can run this back.
05:28 You can say, from this map let's extract the diagram.
05:30 Let's see what the ideas embedded therein are.
05:34 Now one important role of this is if you want to make a change...
05:39 ...you can take your map up to the diagram and plat the diagram in a different terrain; a different site.
05:44 Maybe you'll have a different map, and a plan, but the same diagram.
05:48 And it's a one-to-many relationship.
05:50 There can be many ideas embedded in a diagram.
05:52 A diagram can generate many maps.
05:55 A map can embody many diagrams together, as we've seen.
06:01 In object-oriented terminology then, that sort of idea that's frankly borrowed from Lenaeus, and it manifests in modern programming...
06:11 ...you could say that diagrams are instantiations of ideas, so ideas are classes in a sense...
06:19 ...and diagrams become instances of them, and maps and plans, in turn, are instances of the diagrams.
06:26 And it's a, I believe, lattice rather than a simple hierarchy, so that indeed, a diagram can have multiple ideas.
06:35 And a map can have multiple diagrams.
06:38 But these are three very different levels of inferentional...inferential argument and discourse.
06:47 We talk about the map, so we care whether there's a cliff, and an obstruction, and a south facing.
06:54 The idea was very simple. Two nodes and a line between them.
07:02 So diagrams support logical analysis and inference as well as spatial.
07:09 And that's important, because we talk about these in slightly different terms interchangeably.
07:14 And logical analysis is not necessarily visual, whereas spatial analysis of maps often is.
07:21 And diagrams sit in between here and support both kinds of inference.
07:26 Well, if the cliff is between these things, then there's a problem.
07:30 That's a spatial inference.
07:32 That they are connected is an ideological concept, or even logical.
07:38 I bow to the diagrams made by ModelBuilder...
07:40 ...but they're a small subset of all the kinds of diagrams that we need to be able to support in this process.
07:46 Here's an example from the planning literature.
07:48 This city river district diagram describes the recurring relationship.
07:53 It further suggests potential linkages.
07:55 The same elements that the generic diagram (city center, main street, peripheral 00:08:15
08:03 ...one role of a diagram is to be able to say, what's similar about this situation and that situation...
08:09 ...which are very different terrain and topography, but have similar urban functioning or connected kinds of roles.
08:15 And you could take this diagram and create a map from it.
08:19 Or you could look at a map and derive a diagram from it.
08:22 But we don't have very good tools for doing that other than the human eye-brain combination.
08:29 Here's a diagram that I caught in the wild this fall at the GSD.
08:35 And I didn't have my camera with me, so I had to reconstruct it.
08:39 You may not know what it is yet.
08:41 What if I tell you that's a waterway?
08:46 That's a highway.
08:48 That's some green stuff.
08:51 And that's some built stuff.
08:54 Well, then that diagram can be instantiated.
08:58 And the differences between the instantiation of the diagram can be noted.
09:05 And here's a diagram that's a different plan of the same diagram.
09:11 And the diagram possibly needs yet another diagram that says they don't have to be parallel.
09:17 And the highway doesn't always have to be between the green and the blue.
09:22 And they can go under bridges and get intermixed.
09:25 Those are design concepts that we want to be able to record and move forward with.
09:30 And so, the act of putting down this one is a lot like building a legend.
09:35 And whether the legend or the diagram comes first, I don't know.
09:38 But making a legend and making a diagram are exchangeable, interactive parts of the design process in important ways.
09:47 And there's an instantiation of that, with some green stuff and some gray stuff and a highway.
09:54 And on it goes.
09:57 Diagrams are subject of active research.
10:01 My Ph.D. thesis at MIT had diagrams in the title.
10:04 That was 20 years ago, and in the last decade...
10:07 ...here, for example, is the fifth international conference on diagrams and diagrammatic representation and inference.
10:13 The artificial intelligence community is very interested in these things for, I think, exactly the same reasons I've talked about.
10:20 The interesting potent inferential role they play...
10:24 ...in graphical and visual knowledge and intelligence and other domains of argument and representation.
10:34 So diagrams are distinguished not so much by their graphic style and conventions...
10:38 ...although there are many of them, and we teach and promulgate them and sometimes invent and break them...
10:43 ...but by their roles in design inference.
10:47 And they're not sketches. And they're not maps.
10:49 But they function halfway in between concepts on the one hand and maps on the other hand.
10:59 And that's what makes them, in my view, so potent.
11:03 Whether something is a map or a sketch or a diagram depends a little bit on how it's used, not so much...
11:08 ...you can't always tell by looking at it.
11:12 But I believe they're essential in our GeoDesign enterprise, and that they require their own research agenda and software support.
11:21 Thank you.
© Esri 2013 http://www.esri.com