SDViewer -- Adding Detail: Drill Down to School/Street Segment
This section describes how other mapfiles can be used to add other types of geography. Examples of how mapfiles are added and used are presented. Use of SDViewer project files is described showing how you can modify the scope and types of analysis.
2005 Metropolitan Statistical Areas. The distribution package includes the all U.S. 2005 Metropolitan Statistical Areas shapefile. Click on the Add Layers button, select msa2005r.shp and the following view appears. School districts may now be viewed in the context of metros.
County Boundary File. The U.S. by county boundary file is added with blue boundaries. This mapfile has been added to the project through the use of the WebGeodata tool. The zoom tool is used to zoom into the San Antonio, TX MSA. The identify tool is used to profile the San Antonio ISD school district.
TIGER/Line File; Streets. The TIGER/Line file for Bexar County is added (gray lines). This file has been added to the project through the use of the WebGeodata tool. The zoom tool is used to zoom into the southwest corner of San Antonio ISD. Street detail is now viewable. Labeling is turned on to view names of a few districts near San Antonio ISD.
Schools Point File. The distribution package includes the all Texas schools point file (txschools.shp). This file is added to the project through the use of the AddLayer button. The identify tool is used to profile the Shepard Middle School.
Viewing Street Segment Attributes. The identify tool is used to profile the street segment where the Shepard Middle School is located. Compare the address ranges in the street segment profile in this map with the address of the school in the above map.
U.S. by School District Boundary Files. The default school district boundary files are Census 2000 vintage boundary files. Current definition school district boundary files may be acquired from Proximity and used instead of the Census 2000 versions. The Census 2000 version are used as most districts have not changed boundaries (since 2000) and a wider array of subject matter data exist for the Census 2000 version as compared to other vintages.
Basic Project Files; Opening Your Own Project Files. As described earlier, SDViewer start-up is controlled by three GIS project files (GPRs), one for the contiguous states (sdus.gpr), one for Alaska (sdak.gpr), and one for Hawaii (sdhi.gpr). The three GPR files establish the view that appears in the map windows. Project files are used to automatically open map files that enable viewing certain types of geography, subject matter data, and viewing attributes of each.
School district shapefiles in the project files are as follows:
- Elementary: ussde00.shp
- Secondary: ussds00.shp
- Unified: ussdu00.shp
You may want to change the structure of the project files to meet specific needs. After the project files are created, they are opened using the File>Open Project operation. There is a special rule about project file naming. If the contiguous states GPR is ???us.gpr, then the Alaska GPR must be named ???ak.gpr and the Hawaii GPR must be named ???hi.gpr.
There are many rules about project file content/structure, reviewed elsewhere. But a key one is that all school district layer names must exist in the same manner as specified in the default structures.
Special Data Fields: Locale Code. The locale code might be an attribute of interest and used in a query. For example, setting the QueryList statement to LOCALE='1' would select only those districts categorized as being associated with a "Large City." The locale code is the designation of each district's "locale" based on its geographic location and population attributes such as density. District locale codes are coded in the following manner:
1 - large city
2 - mid-size city
3 - fringe of large city
4 - fringe of mid-size city
5 - large town
6 - small town
7 - rural, outside CBSA/MSA
8 - rural, inside CBSA/MSA