UCGIS Virtual Seminar - Fall 1998 [Back][Refresh][Options][Search] Part 2: Research Questions [Edit*][Delete*] [Image] Part 2: Research Questions - Dawn Wright 09/27/98 Discussion [Image] To move the discussion to research E. Lynn Usery 10/07/98 questions, let me pose an... [Image] [Image] Re: NGS Map Supplement on Byong-Woon Jun 10/08/98 Poplutation and Resources [Image] [Image] National Geographic population Ronald William 10/09/98 map Ward [Image] [Image] stimulate your glands! Wilmot Greene 10/09/98 [Image] [Image] NG caveats forgotton E. Lynn Usery 10/09/98 [Image] [Image] NGS Map Erik Shepard 10/09/98 [Image] [Image] Good comments! Ronald William 10/12/98 Ward [Image] An additional citation to geographic Byong-Woon Jun 10/07/98 representation [Image] [Image] Additional reference E. Lynn Usery 10/08/98 [Image] ... Byong-Woon Jun 10/07/98 [Image] Comment Erik Shepard 10/11/98 [Image] Some final thoughts Erik Shepard 10/12/98 [Image] [Image] Follow up on your comments Kurt L. Johnson 10/22/98 [Image] comment Guangxiang Cheng 10/19/98 [Image] Post new message in this thread ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: September 27, 1998 09:43 PM Author: Dawn Wright (dawn@dusk.geo.orst.edu) Subject: Part 2: Research Questions - Discussion Discussion Topics will include: Process representation Identification of entities and relationships in different problem domains Representation to accommodate interoperability (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1568) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 07, 1998 08:36 AM Author: E. Lynn Usery (usery@uga.edu) To move the discussion to research questions, let me pose another challenge. Check your library or other source for the current issue of National Geographic. Examine the map supplement, "Population and Resources." This static map representation is somewhat deceiving. Pay particular attention to the fires in Africa and the light sources around the world. Were you aware that much of the African continent is on fire? What is wrong? Comment on this "representation" of processes (fire, energy, population increase, etc., for UN regions). How could one better represent the time dimension portrayed on the map for the various phenomena shown? Do you think this map will be easily interpreted by the lay public? Professional geographers and cartographers? (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1763) ----------------------------------------------------------------------- [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 08, 1998 02:14 PM Author: Byong-Woon Jun (bwjun@arches.uga.edu) Subject: Re: NGS Map Supplement on Poplutation and Resources I think the map is a little confusing in representing and visualizing night lights of the world such as fires, fishing fleets, human settlement lights, and natural gas flares. For example, the African continent is on fire. The confusions resulted from two following factors. One is the fact that "it is a static visualization with a fixed data representation attempting to represent dynamic phenomena" as Dr. Usery mentioned. Actually, the National Geographic Inc. used a composite image of cloud-free observations made over a six-month period (Oct. 1994 through Mar. 1995) to represent these dynamic phenomena. The other is the limitations of the traditional paper-based map as a cartographic medium depicting static situations on a plane surface at one specific scale. I think there are two ways to well represent the time dimension portrayed on the map. One way is to make a series of snapshot maps over time and thus show them on a sheet of map at the same time. The other way is to make an animated map using multimedia or hypermedia technology to represent and visualize dynamic phenomena. Any comment? (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1817) ----------------------------------------------------------------------- [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 09, 1998 07:19 AM Author: Ronald William Ward (ronward@arches.uga.edu) Subject: National Geographic population map The National Geographic map you are commenting on is complicated, there again. population is a complicated matter. My opinion is that, given the limitations of the paper map paradigm, National Geographic has put forth a reasonable effort in depicting some of the population variables included in the map. The pattern of fire distribution across the Sahel in west Africa is what I would expect to see in a grassland area dependent on fire as part of its ecological requirements. A caption in the Mid-Atlantic states that the pattern of fire in the area shows fires aggregated for a six month period of time. This seems to me to be explanation enough, as well as serving to reveal the extent to which the Sahel burns over a six month period. With regard to estimating population by use of night time satillite images showing city lights, the authors of the map took reasonable care to explain the many caveats involved in using the map for that purpose (the lack of lights in N. Korea does not mean that that country has a low population). Furthermore, when taken from the context of energy use over six months the map is a more than adequate visualization of the diparity in energy consumption between more developed and less developed countries. Of course, if we can get away from the traditional cartographic paradigm of paper maps and move toward better (and more accessible) representation of time in the virtual environment, then the data show in the National Geographic map could be represented more accurately and with less necessary critical interpretation. As form paper representations, the authors of the map could have shown a concatination of six one month slices - but this may have required even more user interpretation, and thus been more difficult to understand, than the six month aggregate approach. With regard to the map's legibility by the lay public, I do not think the map will be easily understood by most National Geographic readers. Especially if we consider that maps should be designed to show a large amount of information at a glance, then I must admit that a great deal of misinformation could be extracted from National Geographic's mode of representation. On the other hand, I don't know if it is a good idea to design a complicated representation such as this so that the lay public doesn't have to closely read a caption or ten. The map is covered with explanitory captions explaining all relavent caveats - people should read these captions. As for professional geographers and cartographers, no group of professionals should be held more responsible for reading everything included on this map than geographers and cartographers. Again, when all is said and done, I think the cartographers at National Geographic did a pretty good job for a paper map. Perhaps the main issue encompassed by this map is not the poor representation of time, but the necessity to develop representational methods through and past the traditional cartographic paradigm. Ron Ward (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1829) ------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 09, 1998 09:21 AM Author: Wilmot Greene (mot@uga.edu) Subject: stimulate your glands! I am going to have to disagree (with a touch of hesitation) with Ron here. Ron, you wrote " Especially if we consider that maps should be designed to show a large amount of information at a glance, then I must admit that a great deal of misinformation could be extracted from National Geographic's mode of representation." The word that gives me a problem here is the word "should". Road maps that you buy at a gas station 'shoud' be designed to be easy to read, but not N.G. maps. I would personally be dissapointed if I could ingest an entire N.G. map in minutes. I am sure that I am not the only one of us who gets excited when I go to the mailbox open the N.G. and see the issue contains a map. It is fun to actually read and slowly decipher these maps, so if it takes a while,,,thats ok. I think the layperson could avoid misreading this map if he/she put some time into it, and if they don't invest thier time into reading the map fully, then that is not the cartographer's fault. Right? We know Carl Sauer ( i think ) said "maps should stimulate our glands" well, this map is no quickie! However, I do agree that the time element in this map is ,,,well,,, improvable. Mot (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1835) ------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 09, 1998 01:16 PM Author: E. Lynn Usery (usery@uga.edu) Subject: NG caveats forgotton While NG does provide explanation of the 6 month composite image, the fact that a satellite sensor is easily saturated with bright objects (fire, lights) is not discussed. For example, it has been demonstrated that a single 18" reflective mirror will completely saturate an 80 meter instantaneous field of view (IFOV) of a satellite sensor (This was done with early Landsat MSS). In reality, does the whole of the African savanna burn every 6 months? Actually the representation presents many small fires in a series of images which when composited appear much larger than they really are. This explanation for the resulting presentation is certainly not common knowledge to the lay public and probably not common to many professionals. From a representation point of view, I think we have to do much better than the NG map at conveying geographic information over time. Hopefully, this discussion and the readings will stimulate some of our bright young students to attack some of the representation problems. (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1837) ----------------------------------------------------------------------- [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 09, 1998 11:39 AM Author: Erik Shepard (shepard@uga.edu) Subject: NGS Map Some good points were made both by Ron and Mot. To stray a little from the representation discussion, I think that we do definitely need to consider our audience. A road map is indeed designed to be quickly glanced at (I hope! I don't want to drive down the road next to the person who has to scrutinize their map closely!) while maps such as the National Geographic map are meant to convey a lot more information and can tolerate a bit of ambiguity because the user is expected to examine closesly. As far as representation goes, I don't know that we will ever find a good way in traditional cartographics to represent time. I mentioned the possibility of acetate overlays in the discussion the other day; beyond something like this, though, there is the problem that paper is static and time (by definition) is not. The two are add odds with each other. We've considered mathematical models as descriptors of time functions. This will work fine in an interactive system like a computer, but again with paper this still is not good since we have trouble plotting these functions in the first place. My (perhaps argumentative) contention: 2 dimensional paper maps will never be able to give a good representation of temporal data (unless we ignore some other dimensions of the data). (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1836) ------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 12, 1998 12:12 PM Author: Ronald William Ward (ronward@arches.uga.edu) Subject: Good comments! Erik, "As far as representation goes, I don't know that we will ever find a good way in traditional cartographics to represent time. I mentioned the possibility of acetate overlays in the discussion the other day; beyond something like this, though, there is the problem that paper is static and time (by definition) is not. The two are add odds with each other." I would agree that this is certainly the case. As the use of computers becomes more and more prevailant, we should see the end of traditional paper maps at some point. Of course this brings up issues of accessibility (save it for GIS and Society), but consider how common televisions are in our society - for better or worse, TVs are ubiquitous across economic class distinctions. Consider again that TVs are not as ubiquitous in other parts of the world - but time being what it is (marching forward), and some personal experiences included, it's just a matter of time before most people who want a TV will have one. Computers, and hence virtual 3-d animated maps, I would expect to follow that same course. Ron Ward (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1883) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 07, 1998 11:14 PM Author: Byong-Woon Jun (bwjun@arches.uga.edu) Subject: An additional citation to geographic representation I'd like to provide an additional citation to geographic representation for you. Here is the article: Smyth, C.S., 1998, "A Representational Framework for Geographic Modeling", in Egenhofer, M.J. and R.J. Golledgem (eds.), Spatial and Temporal Reasoning in Geographic Information Systems, New York: Oxford University Press, pp. 191-213. Geographic modeling is the representation of complete spatio-temporal environments in geographic space and time. This article presents a conceptual framework for representation of geographic modeling. The framework presented is suited for developing representations appropriate to specific applications. The framework consists of a representational theory structured as an abstraction sequence. The elements of the sequence are (1) an explicit ontology, (2) an expression of that ontology in a formal system, (3) a model design in terms of a computational model of that formal system, (4) a realization of the computational model in a concrete implementation. The sequence organizes the development of a geographic model. It can also provide a feedback mechanism that allows the representational theory to be just complex enough to meet the needs of a particular application. The theorectical basis for a representational framework can be drawn from many spatial and temporal models and practice of cognitive science, computational gemetry and computer-aided design, artificial intelligence, GIS, temporal databases, mathematics, physics, and simulation systems. The article argued that applied on a conceptual or meta-level, the framework can aid in the construction of more general purpose geographic information systems. Hope you find it to be informative. (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1795) ----------------------------------------------------------------------- [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 08, 1998 01:13 PM Author: E. Lynn Usery (usery@uga.edu) Subject: Additional reference Thanks Jun for providing the reference. This reference complements the existing set very nicely and will help us understand the "basic requirements" for a general purpose representational theory. Can others provide additional references? (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1809) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 07, 1998 11:15 PM Author: Byong-Woon Jun (bwjun@arches.uga.edu) (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1796) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 11, 1998 02:34 PM Author: Erik Shepard (shepard@uga.edu) Subject: Comment Just a comment. I finally got around to reading *last* month's GIS world, which had an article on temporal GIS. I thought that it was interesting that they discussed many of the potential applications for temporal GIS, but did not have any discussion on temporal data models. (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1858) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 12, 1998 01:38 PM Author: Erik Shepard (shepard@uga.edu) Subject: Some final thoughts Now that we are onto a new topic, I thought that I would post what I found to be some of the most salient points of the discussion. It seems to me that the big areas for GIS research in representation are in incorporating truly spatial (i.e. 3D) and temporal data as well as work examining breaks away from the traditional map model (i.e. using spherical coordinates vs. planar coordinates and using "predicitive" mathematical models instead of sampled data). Object-oriented design, in my opinion, lends a lot to help us structure our thoughts and lets us develop them in relative safety but does not develop the model for us. Moreover, it seems as though we need some sort of unifying element to geographic data instead of raster vs. vector, etc. A final concern that we always need to be concerned with is the idea of backwards compatibility. There are literally terabytes upon terabytes of data which have already been generated in one or more of the existing representations. We need to make sure that we preserve enough of these representations to convert our existing wealth of knowledge. (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=1893) ----------------------------------------------------------------------- [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 22, 1998 09:23 AM Author: Kurt L. Johnson (Kurtljohnson@worldnet.att.net) Subject: Follow up on your comments I agree Erik, much like your stated comments, the biggest mountains to climb are the 3-D and the temporal ones. However, I would also add in the difficulty of representing data at the "atomic level of detail". We seem to have a pretty good handle on collecting that level of sophiscated data today. As things get more and more detailed and specific, it gets harder to describe them taxonomically while maintaining some level of compatability with the rest of the database. I admit my computer background is slim to none, but it is hard for me to fathom how to accomplish this. See ya (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=2214) ------------------------------------------------------------------------ [Top][Previous][Next][Print][Reply][Edit*][Move*][Delete*] Date: October 19, 1998 10:17 AM Author: Guangxiang Cheng (gcheng1@tiger.lsu.edu) Subject: comment Due to the more complex approaches on spatiotemporal phenomena in GIS, more efforts should be put in this area. In the discussion of priority areas for research, most priorities are to solve dynamic phenomena in GIS. I think it is appropriate. (http://forums.library.orst.edu/forums/Index.cfm?CFApp=7&Message_ID=2108)