SDO_GEOMETRY is an Oracle spatial database object type that can be used to store a wide variety of spatial data like points, lines, polygons etc. Different mapping tools like Shape Objects, Shape Viewer etc., or full featured GIS products like ArcGIS, are used to visualize spatial data. These mapping tools for visualizing and analyzing spatial data primarily expect the input to be in the form of ESRI shapefiles. Shapefiles provide a simple, non-topological file format for storing geographic and attribute data. It is comprised of three main files with extensions .shp, .shx and .dbf. The .shp file has geodetic descriptions, the .shx file is an index into the shape file, and the .dbf file contains the descriptive attributes of the spatial object, such as name, area, length, population, etc. This thesis concentrates on developing a software tool to convert Oracle spatial tables, which contain an SDO_GEOMETRY column, into ESRI shapefiles to achieve the inverse functionality of shp2sdo, available on Oracle website.
To be precise, the SDO_GEOMETRY column in an Oracle spatial table has the locational information, and this is transformed to .shx and .shp files; the non-locational information in the table is translated into a .dbf file.
Spatial data is used by GIS (Geography Information System), the technical side of geography, and many other related fields such as geology. Proper storage of spatial data is of utmost importance. Oracle spatial geometry type SDO_GEOMETRY is the primary way to store spatial data in oracle tables. Different shapes like points, lines, polygons, circles etc. can be stored using SDO_GEOMETRY objects.
ESRI (Environmental Systems Research Institute) shapefiles or simply shapefiles are a popular file format for storing geospatial data. The data for a feature is stored as a shape comprising a set of vector coordinates. It is developed and regulated by ESRI as an open specification for data interoperability among ESRI and other software products. It can be used to describe geometries like points, polylines, polygons etc. which can represent rivers, boundaries etc.
The purpose of this software tool is to convert the spatial data stored in Oracle tables to shapefiles which can be displayed using mapping tools (like map objects, shape viewer, ArcGIS) that are readily available. This tool renders geospatial data, stored in a database, in visual format that can be easily understood and analyzed by anyone.
Viewing Oracle spatial tables does not require a transformation to a shapefile. Oracle provides a Map Viewer tool, not packaged with Oracle and Oracle spatial, for viewing Oracle spatial data. Map Viewer uses ORCL, essentially a Java servlet engine written by Oracle. It is not an easy utility to use and can have a steep learning curve. One of the advantages of this thesis is to broaden the visualization choices available and also to have a spatial mapping tool that is far easier to use than Map Viewer.
The user manual with a brief description of the tool and how to use it, can be obtained from here
The ReadMe.doc file for the sd2shp tool, that gives information on how to download and run the tools can be obtained from here
The SDOtoShp GUI tool (run by just double clicking it) can be downloaded from here and the command line tool (run in the command tool window) can be downloaded from here