generating the maps
Once the field data collection is complete, the process of
creating the maps can begin. There are several items that serve as an aid in the
production of the high-quality mapping product. These items include: the
collected data, engineering drawings, digital orthophotography, and a mapping
application to pull it all together.
The ArcGIS Desktop
The Environmental Systems Research Institute (ESRI) was founded in 1969 at Redlands, California and has become a world leader in Geographic Information Systems (GIS) software. The ArcGIS Desktop is a scalable family of software for geographic data creation, integration and analysis. The ArcGIS Desktop consists of: ArcReader/ArcExplorer, ArcView, ArcEditor, and ArcInfo.
Small utilities that do not want to edit the data that has been collected, but would like to do some simple viewing and printing on their PC can use ArcExplorer. ArcExplorer allows the utility to import different shapefiles and label/re-label features in their system. It also allows for the replacement of outdated shapefiles with current or better ones. For example, if a system/city is photographed with higher resolution photography, those older aerials can be taken out of the existing digital map file and the newer aerials can be imported without re-publishing. There is no charge for ArcExplorer software as it is a viewing software only. It is similar to Adobe Acrobat Reader in that regard.
ArcView will allow a utility to edit or build its own maps. The layers creating the map must be in a shape file format. The shape file is an ESRI file that contains shapes (points, lines, and polygons) and allows for some basic information (attributes) about the shapes. KRWA can provide some simple programming applications to make things easier for the utility. KRWA has used these Visual Basic Applications (VBA) to allow a client system to select a waterline and be able to easily change the diameter, type of pipe, year installed, etc. The cost of ArcView is approximately $1,500 to $2,000.
If it is necessary for the utility to have their information in a geodatabase, they must have ArcEditor or ArcInfo to be able to use the full abilities of a geodatabase. The best reason to use a geodatabase is to be able to use the utility network tools. The utility network tools will allow a user to click on a waterline with a leak and highlight what valves need to be closed to isolate the line. There are certain tracing features to show water flow direction among other things, but the tool used the most by utilities is to highlight valves to isolate a water line.
Most of the small communities do not need these capabilities. In Garden City, KS for example, these capabilities are used, but the city recognizes it has a very complicated distribution system. Cities half the size of Garden City or a population of 15,000 may be able to use these tools, but a town the size of 10,000 or less may not get much use from them. In addition, a high level of software familiarity is essential.
Layers, Themes, and Transparencies
Using the ArcGIS Desktop requires some skill and specialized training. It is similar to a CAD application in that it uses layers (ArcView calls them themes) synchronized to a coordinate system. The themes can be compared to sheets of transparencies. The transparencies can consist of: digital orthophotography, the collected points, sections and section lines, roads and road names, and the digitized or created system features. The themes are stacked and when looking through them all, just as you would a stack of transparencies, it all comes together to create a base map.
Attributes are information in the database about the feature. Examples are: pipe size, pipe type, and date of installation. These details can be integrated into ArcView with some of the previously mentioned visual basic applications as a "link" to a feature, but to gain the full use of the data ArcInfo is required. Full use is defined as searching, sorting, preparing reports, identification utilities, etc.
The attributes in both cases work best when formatted into a data model. A data model is a simple list of attributes that pertain to each class of feature, classes such as valves, meters, lines, or hydrants. You can create a specialized data model or use an existing data model. When using an existing data model, you only need to use the fields that are relevant to your project.
|Sample Data Model|
|ESRI Data Model - Pressurized Main|