Digitization and Computerization of River System Coordinate Geometry: Project Completion Report

Abstract

A means of referencing various entities along a given stream course is the river mile index. This gives the location relative to the coordinate geometry of the river system. This type of referencing is very useful to a number of agencies both within the State and at higher levels. Detailed map coverage of the State has not been available until recently with the production of 7-1/2 minute orthophoto maps of the entire State of Arizona. Since these maps were produced from imagery obtained during 1972-73, the State has a fairly definite point in time with which the maps were produced. The existing U. S. Geological Survey maps varied by up to 50 years in their generation. A scheme was worked out and six orthophoto maps were annotated using that method for an area around Tucson, Arizona. The problem of developing a computer software package to produce river mile indices was begun but soon shown to be too vast in scope to accomplish all that was desired. Several existing similar programs were examined. The U. S. Environmental Protection Agency (EPA) has a program AUTOMAP which is designed to do all that was sought to be done and much more. The development of a small, crude, local computer program was abandoned. Linkage to the EPA program AUTOMAP was sought and will be effected soon. The enlargement of project scope and envolvement meant that the pilot project was absorbed into a now ongoing activity to digitize the main stream channels and ancillary data. This new enlarged project, with funding from other sources, should be completed this year. The OWRR project may be thought of as the seed of the large project now being conducted. Without the seed the present status would not have been realized.