A 3.044Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
This review requires some background. My county has a Geographic Information System (GIS) parcel base. It delineates boundaries. Should it be under the control of a planner, a computer specialist, a geographer or a surveyor? I believe that this is the most important question that needs to be resolved in this decade.
Needless to say, I am in favor of, at a minimum, surveyors having control of anything in the GIS that has to do with legal boundaries. Surveyors understand the mathematics and the leg al principles. I also believe that surveyors should control the control. This, or course, will necessitate learning more about GISs, (knowledge which should be tested in the required examination).
Perhaps this is the time to address what I see as a major obstacle. As surveyors, we have been concerned with our own hard-earned data in which we take great pride. We use other people’s surveys. When we do, we verify the data and by law and custom become accountable for the accuracy of whatever data we use. One of the advantages of a GIS is the ability to use other people’s data, and yet for surveyors, the use of other data for which it is not possible to ascertain the reliability is very foreign to us. Still, we use USGS Quads all the time, and although we would never set a boundary with one, we still find them useful. So consider, if you will, the possibility that we might find uses for the data available from the many, many sources of GIS data.
That would be a good reason for adding GIS to what we do now. Can surveyors expand the kinds of services we offer? I hope so. Technology continues to encroach on the kinds of information for which surveyors were once the sole suppliers. Shall we be reduced to masters in the eyes of the courts who are called on to decide on boundary disputes? But I digress.
One of the reasons that many surveyors have not embraced GIS is that the leading software programs cost thousands of dollars and require a huge learning curve. Is Manifold System a real GIS program? I will let you judge for yourself after reading this review.
Manifold System is marketing a GIS for $245.00. What do you get for $245.00? You get a real GIS. You get more than 3000 pages of documentation on the disk. You get a tutorial with a step-by-step on how to use their GIS, and you can download the document “How Do I Do This in ArcGIS/Manifold: Illustrating Classic GIS Tasks,” by Arthur J. Lembo, Jr., of Cornell University.
Figures 1 and 2 show the opening screen. On the left is the graphic screen and on the right is the project screen. In Figure 1, I have selected the File Menu and under that the Import to show the wide
selection of importable types. I selected Drawings, which brings up the screen in Figure 2. As you can see, you can import a huge selection of different types of graphics (and their attendant database files where available). I have selected MapInfo files (*.mif) and opened all that were available on the
Manifold System disk. These are shown in the Project Window. Each one of these projects has a graphics file and a table (database file). You can look at the graphics file and/or the table by double clicking on it. So what?
Everything on a computer-generated map is referenced to a particular coordinate system. This could be said of CAD drawings as well. How is that different from geo-referencing? No difference except that the coordinate system is in latitudes and longitudes (standardized to a mathematical model, for example, WGS84). For mapping, this 3D coordinate system has to be projected onto a plane surface. An example of a plane coordinate projection is the State Plane Coordinate System. All such systems project objects in 3D space onto a 2D surface. Look again at Figure 2. When new information is added, the database tables are immediately upgraded, as are the drawings. Just click on the table and click on the item to be edited.
Figures 3 and 4 show how simple it is to change the coordinate system of a drawing. In Figure 3 the main body of the United States is shown in latitudes and longitudes. It looks strange when displayed on a flat surface. To project the map onto a flat surface or to change the projection to a different projection, go to the Edit Menu and pick Projection. You are presented with many different projections. You probably won’t know the proper parameters. Just select the Suggest button and a proper set of parameters for the projection you have selected appear. The Lambert Conformal Conic is a popular projection, and as you can see in Figure 4, it is the projection one most often finds for maps of the mainland. Another important fact is that when you set the base map at the projection you wish, all other data will automatically be brought into the map in that projection.
Figure 5 shows my old friend, Dona Ana County Parcel Map. Manifold System points out one of the shortcomings of Shape files, that is, projected Shape files do not contain the pro-jection information; therefore, although the projection in NAD83 State Plane Coordinates in feet, New Mexico Central (and cursor position correctly specified) the units are still indicated as latitude and longitude. Unless otherwise directed, Manifold System assumes that coordinates are geodetic. ESRI seems to have abandoned *.shp in favor of a new standard file type, *.lyr (layer), which is the one standard file type that Manifold System cannot read as yet.
Figure 5 also demonstrates one of the improvements Manifold has brought to GIS. You can get tabular information on anything by double clicking it. Note that a feature is highlighted and can be edited directly. Note also that you can print out the tabular data directly. You can also show the intrinsic tabular data (the area, type, number of legs, defining coordinate, the latitude and longitude, etc.). There is a lot of information at your fingertips.
The Manifold tutorial shows you where and how to download free GIS data from the U.S. Government (there is an enormous amount of free data available). The kinds of data you may not have seen are census data, and topographic data.
I recently read a GIS magazine that will be publishing a regular column to educate geographers and the like in surveying. The overlap of surveying and GIS is growing and the availability of positional information with RTK is shrinking the area of surveying expertise. We do not have the luxury of ignoring GIS. Manifold System is the least expensive way in both time and money to correct this blind spot. The hands-on experience you will gain using the Manifold System will bring you up to snuff faster than a class or course. If we are as smart as we think we are, we should be able to learn G I S faster than the geographers can learn surveying.
Joe Bell is licensed in California and New Mexico. He has been reviewing software for surveyors since 1982.
A 3.044Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE