GIS in the Library

I have several agendas:

The regional focus makes the project clear, at least in terms of what lies on the bottom layer: a base map of Rockbridge and adjacent counties, to which layers can be added by various interested parties, in aid of various projects contained within that space. I don't know exactly HOW that base map gets made, though I presume it could be built from the topographical maps which I think David Harbor already has in digital form --and presumably in a form that ArcView can display.

I'm imagining that a user could call up the base map and the topo layer, and then make a new layer with additional information --blast furnace locations, or mines, or hydrology, etc.-- either by entering directly onto the new layer via ArcView, or by importing a layer made with, say, ArcInfo or maybe with another translatable format like DXF.

Eventually there would be a catalog of available layers, among which a user could choose, and which the map server would deliver to the web. Some projects would use only small parts of the region (Woods Creek watershed, say, or the hinterland of Glenwood furnace, or trails in the James River Face), and a user would zoom in to see the detail.

There are so many existing maps of Rockbridge and environs, many of which might eventually join this archive as the time and effort was allocated to transfer their contents to digital form. I don't know of any effort like this, but it seems like such an obvious thing to do that SOMEbody must have played with something similar...

One unknown is compatibility of existing digitizers with existing software --whether the Geology Department equipment will work with ArcView, whether the CAD software in Physics & Engineering will produce files that can be transferred to something readable by ArcView, whether the sort of registration I used to do with AutoCAD is practical... if it was, then a basemap could be plotted for entry use with a big digitizer. Basically, the question for the UVa visit is: how do the digitizers interconnect with ArcView? What steps does a user have to go through to actually MAKE a map in electronic form, starting from a paper map?

A while ago I grabbed ARC/INFO export files for Rockbridge (see C:\rockbr\), from the TIGER data provided by UVa, but I don't know how to get them translated into something that ArcView could open --seems that the ARC/INFO command 'IMPORT' is necessary --and indeed there is an Import utility (import71.exe) with ArcView.

A look at Getting to Know ArcView GIS indicates that shapefiles can be created converting existing features into shapes and by drawing new shapes... You can convert features in themes created from ARC/INFO coverages, SDE database files, and CAD drawings into shapes. You can also 'convert' features that are already shapes and save them in a new shapefile. This lets you extract selected features from a large theme and create a smaller theme with only the desired features... (pg 23-2)
In the example they give, an air photo is marked up, using Draw tools, but it's not really clear how the original air photo got into ArcView. Can a JPG be used somehow? ("ArcView supports images and grids for display only" --p 8-3, and there's an example using "Image Data" as a Data Source Type, but the stuff bundled with ArcView 3.1 includes JPG image support, it says). And presumably digital orthophoto quads can be used, and raster maps of quads too. summarizes support for image format issues, in the context of what comes with the SDchool/Library bundle.

It does seem that various extensions enlarge the possibilities: a digitizer extension [which is free], the CADReader extension [also free], the Spatial Analyst extension (not free, but allows one to "create and analyze grid themes" --p 8-3) are mentioned. But just HOW one assembles data and views and shape files is still a bit murky --and it seems like it would matter quite a bit what choices were made in setting up the base map layer(s).

A look at Processing Digital Images in GIS (Verbyla and Chang, SCIENCE G70.212 .v47 1997), which covers both ARC/INFO and ArcView and answers quite a few of the questions above. And features like Hot Link (which can open a text file, an image, an ArcView document or project, or run an Avenue script) are described, with step-by-step directions. Some operations can't be done with ArcView, but can be imported from ARC/INFO --thus, the REGISTER command in ARC/INFO is an interactive utility for affine transformation in image rectification (unwarping images). It appears that Avenue and Spatial Analyst can be combined to accomplish muchh the same thing (pp 181-184).