The Salt River Pima-Maricopa Indian Community (SRPMIC), a 52,000-acre settlement of Native Americans adjacent to Scottsdale, Arizona, is implementing a unique GIS to serve its citizens. Based on Esri's ArcInfo software, the SRPMIC's GIS will develop an extremely accurate cadastral measurement database maintained by surveying and legal description data. Unlike traditional coordinate-based mapping systems, the SRPMIC's measurement-based GIS will store the originating surveying measurements to create an accurate, verifiable cadastral base, rather than obtaining discrete coordinates derived from digitizing existing source maps. By storing the cadastral measurements, the SRPMIC's GIS database can be automatically readjusted whenever datum changes or survey control modifications occur. Additionally, an online record of the originating legal descriptions, as well as a complete cadastral chronology, will be stored simultaneously as the SRPMIC's digital cadastre is developed over time. In effect, the GIS graphics representation for the Community will be created and automatically maintained through the input of textual legal descriptions. This paper examines the database design and implementation issues for the SRPMIC's measurement-based GIS and explores concerns endemic to Southwestern Native American GIS developments in general.
The Texas Department of Transportation recently began a pilot project in the Odessa District to capture differential GPS, inertial data, georeferenced digital images and inventory data on approximately 6000 miles of West Texas roads for their GIS applications. This project is the culmination of an effort, begun within the District in 1988, to display roadway information on digital maps. Odessa's GIS aspirations began by simply manually coloring maps to illustrate roadway sections to be evaluated during each pavement analysis cycle. Because this process was cumbersome and time consuming, it resulted in a less than satisfactory result. Soon thereafter, the Texas DOT implemented a linear referencing system (Texas Reference Markers or TRM) on the roadway network. This system provided a method to identify each data element with a unique key along with markers that were clearly visible in the field. The Texas Reference Marker system became the backbone of a roadway inventory and pavement condition database. The Texas DOT has reviewed a variety of GIS software solutions. As an interim step, and prior to the commencement of this current project, the Odessa District along with TxDOT's Design Division created GPS based county maps with alignments and reference markers on them using SAS Graph. This method provided the District with its first, clearly crude GIS capability. At the same time, the District began to look at updating its photolog (last updated in 1985) in 1992. The photolog was used to document remote project sites, inventory project requirements and prepare plans in the office. The District began evaluating a variety of updated videologging and software tools and planned to procure a new system in 1993. That effort was canceled. However, in late 1994 and early 1995, the District again reviewed new imaging and software tools as part of its GIS plans. The District procured georeferenced digital images, o-GPS and inertial data, Mandli Roadview IV software for ArcView 2.1 and Mandli Roadview Inventory Software. The georeferenced digital images are used to populate, verify and update sign, feature, bridge and surface condition inventories in a Sybase relational database. The georeferenced images are stored on a 90GB RAID (Redundant Array of Inexpensive Disks) based server so that all network users have access to them. A RAID based solution provides a very high performance server, compared to jukebox or obsolete videotape based solutions. The sign, surface condition and milepost databases are used within Texas' ArcInfo, ArcView, Roadview and Sybase environment for analysis and planning purposes.