APPENDIX D: SPATIAL DATA ENGINE PROTOTYPE FOR THE MISSISSIPPI
CHRIS REWERTS, CERL
The Mississippi Valley Division (MVD) and the Environmental Systems Research
Institute (ESRI) undertook a cooperative experiment to use ESRI software to manage
MVD data. This experiment was supported in part by the US Army Corps of Engineers
Construction Engineering Research Laboratories (CERL) for the purpose of gaining
understanding of the software tools and their application to real data and operational situ-
ations to address a need. This document reports on observations made during the 12 May
1998 demonstration of the software usage prototype presented by ESRI at the MVD.
Mississippi Valley Division
The MVD comprises all the US Army Corps of Engineers districts that have in com-
mon the Mississippi River System. Previously, the river flowed through two Corps divi-
sions: the Upper Mississippi Valley region (referred to here as UMV) included the St. Paul
and Rock Island Districts of the former North Central Division, and the former Lower
Mississippi Valley region (referred to here as LMV) consisted of the Memphis, Vicksburg,
and New Orleans Districts. What makes the joining of UMV and LMV notable in this
report is that the format of spatial data used by the two are different; more specifically, the
software used to create and maintain the data for the two previous divisions are different.
With a new mission to focus collectively on the entire Mississippi River System, one of
the problems faced by the MVD is how to share and integrate disparate formats of data.
ESRI's SDE (Spatial Database Engine) software is being investigated as a technology that
may provide part of the solution.
The data are primarily geospatial or geographical information system (GIS) data.
These spatial data are also connected, linked, integrated, or associated with tabular data.
The Upper Mississippi Districts are using ESRI's ARC/Info as their GIS, with tabular
data stored as attribute tables in the GIS. The LMV Districts are using Intergraph Cor-
poration's MGE (Modular GIS Environment) for their GIS and CADD (computer-aided
design and drawing) needs, with tabular data stored in SQL*Server (a Microsoft relational
database management system) tables that are linked to spatial features stored in MGE.
These components are part of the Regional Engineering and Environmental Geospatial
Information System (REEGIS), which consolidates all engineering and environmental
data for the Lower Mississippi River System into a standardized geospatial database.
SDE is middleware software that provides linkage between GIS and RDBMS. Essen-
tially, it enables storage of geospatial data in the RDBMS, allowing the exploitation of
two mature software technologies, GIS/CADD and RDBMS, in concert. In addition, SDE
stores and retrieves the data in such a way that they can be accessed and used by a vari-
ety of GIS softwares from various hardware architectures. For example, in the case of
the MVD demonstration, ARC/Info data loaded into the SDE database could be accessed
using not only ARC/Info but MGE as well. Without SDE, ARC/Info data would have to
undergo arduous conversion to MGE format for this to be possible. SDE CADD client
software enables MGE data to be loaded into the SDE database and then accessed by
This description of SDE and SDE CADD client software is extremely brief, since much
more thorough information is available at the ESRI Web site at http://www.esri.com/