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Ann Arbor GIS Metadata

Ann Arbor Geographic Base File (AAGBF)

Category Administrative/Ownership Data Base
Name

aagbf

Type ArcInfo Coverage
   
Abstract The Ann Arbor Geographic Base File (AAGBF) is comprised of two related components; graphic features consisting mainly of street centerlines, and descriptive information regarding address ranges, census geography, and voting/ administrative districts. This data layer is important to all applications which deal with address matching, voting districts, and demographic characteristics.
   
Maintenance Staff audited address and district designations using PC ArcInfo in 1990. Repositioned graphics to match planimetric features using Unix ArcInfo in 1994, and interfaced with Sybase in 1995 and MS SQL Server in 1998. Presently, update of detailed graphic and attribute information continues using the GBF Maintenance Application developed in Arc Macro Language (AML) by ITSD. Future plans include extension of detailed graphic and attribute data into the expanded Large-Scale GIS Data Base Update Project Area (1997).
   
Source 1990 TIGER Census Geography
   
Agency/Contact Information Technology Services Department / mjohnson@ci.ann-arbor.mi.us
   
Accuracy National Map Accuracy Standards for 1"=100', 1-2 foot positional accuracy
Projection NAD83 State Plane, Michigan South Zone 6401
Units US Survey Feet
Spheroid GRS1980
   
Domain Large-Scale GIS Data Base Development Project Area extended to 48000' by 48000' tile boundary
Format Double Precision Network Coverage, Polygons with INFO attributes, Arcs with INFO attributes and related SQL table AAUIS.GeoBase
Count 1729 Polygons, 7031 Arcs
   
Qualifications Information stored in the SQL table AAUIS.GeoBase is linked through a common unique key, GeoBase_ID, that is shared with the Arc Attribute Table (.AAT). The SQL table contains the same address range, street characteristic, and administrative/voting district attributes as the .AAT, plus additional fields relating to update tracking.

The .AAT contains essentially the same administrative/voting district attributes as the Polygon Attribute Table (.PAT), and includes street characteristics and address range information.

Qualifications The best source of ZIP Codes is the SQL AAUIS.Address table which is used by many City applications. Due to nature of the way in which ZIP Codes are assigned to frontages along street center lines, the aagbf layer does not represent ZIP Codes accurately.

Census Place attributes have not been completed and usage is questionable.

Assignment of Theoretical Address Ranges was only partially completed. Future plans include finalization of that assignment.

AAGBF.PAT - Polygon Attribute Table Definition and Content

Column Field Name Width Output Type N Dec Alt Name Indexed? Field Content
                 
1 AREA 8 18 F 5   - Polygon Area (square feet)
9 PERIMETER 8 18 F 5   - Polygon Perimeter (feet)
17 AAGBF# 4 5 B -   * Polygon Internal ID
21 AAGBF-ID 4 5 B -   - Polygon User Assignable ID
                 
25 ZIP 11 11 C -   - ZIP Code
30 PLACE 4 4 C -   - Census Place 1990
34 TRACT 6 6 C -   - Census Tract 1990
38 BLOCK 3 3 C -   - Census Block 1990
41 NEIGHBORHOOD 3 3 C -   - Neighborhood
44 SUBNEIGHBORHOOD 2 2 I -   - Sub-Neighborhood
46 WARD 1 1 I -   - Ward
47 PRECINCT 2 2 I -   - Precinct
49 SUBPRECINCT 2 2 C -   - Sub-Precinct (splits)
51 COUNTY_COMM 2 2 I -   - County Commissioner
53 STATE_HOUSE 2 2 I -   - State House
55 STATE_SENATE 2 2 I -   - State Senate
57 US_HOUSE 2 2 I -   - US House
59 POLICE_DIST 1 1 C -   - Police Patrol District

AAGBF.AAT - Arc Attribute Table Definition and Content

Column Field Name Width Output Type N Dec Alt Name Indexed? Field Content
                 
1 FNODE# 4 5 B -   - From Node Internal ID
5 TNODE# 4 5 B -   - To Node Internal ID
9 LPOLY# 4 5 B -   - Left Polygon Internal ID
13 RPOLY# 4 5 B -   - Right Polygon Internal ID
17 LENGTH 8 18 F 5   - Arc Length (feet)
25 AAGBF# 4 5 B -   * Arc Internal ID
29 AAGBF-ID 4 5 B -   - Arc User Assignable ID
                 
33 GEOBASE_ID 5 5 I -   * Unique ID Link
38 ST_DIR_PREFIX 2 2 C -   - Street Direction (Prefix)
40 ST_NAME 30 30 C -   - Street Name
68 ST_NAME_SUFFIX 5 5 C -   - Street Type
72 ST_DIR_SUFFIX 2 2 C -   - Street Direction (Suffix)
74 ST_CLASS 4 10 B -   - Feature Classification Code
                 
76 LT_PARITY 1 1 C -   - Left Side Designation
77 AC_LT_LO_ADDR 4 10 B -   - Actual Left Low Address Number
81 TH_LT_LO_ADDR 4 10 B -   - Theoretical Left Low Address Number
85 AC_LT_HI_ADDR 4 10 B -   - Actual Left High Address Number
89 TH_LT_HI_ADDR 4 10 B -   - Theoretical Left High Address Number
93 LT_PLACE 4 4 C -   - Left Census Place 1990
97 LT_ZIP 11 11 C -   - Left ZIP Code
102 LT_TRACT 6 6 C -   - Left Census Tract 1990
108 LT_BLOCK 3 3 C -   - Left Census Block 1990
111 LT_NEIGHBORHOOD 3 3 C -   - Left Neighborhood (GEO)
114 LT_WARD 4 10 B -   - Left Ward
115 LT_PRECINCT 4 10 B -   - Left Precinct
117 LT_SUBPRECINCT 2 2 C -   - Left Sub-Precinct (Split)
119 LT_COUNTY_COMM 4 10 B -   - Left County Commissioner District
121 LT_STATE_HOUSE 4 10 B -   - Left State House District
123 LT_STATE_SENATE 4 10 B -   - Left State Senate District
125 LT_US_HOUSE 4 10 B -   - Left US House District
127 LT_POLICE_DIST 1 1 C -   - Left Police Patrol District
                 
Column Field Name Width Output Type N Dec Alt Name Indexed? Field Content
                 
128 RT_PARITY 1 1 C -   - Right Side Designation
129 AC_RT_LO_ADDR 4 10 B -   - Actual Right Low Address Number
133 TH_RT_LO_ADDR 4 10 B -   - Theoretical Right Low Address Number
137 AC_RT_HI_ADDR 4 10 B -   - Actual Right High Address Number
141 TH_RT_HI_ADDR 4 10 B -   - Theoretical Right High Address Number
145 RT_PLACE 4 4 C -   - Right Census Place 1990
149 RT_ZIP 11 11 C -   - Right ZIP Code
154 RT_TRACT 6 6 C -   - Right Census Tract 1990
160 RT_BLOCK 3 3 C -   - Right Census Block 1990
163 RT_NEIGHBORHOOD 3 3 C -   - Right Neighborhood (GEO)
166 RT_WARD 4 10 B -   - Right Ward
167 RT_PRECINCT 4 10 B -   - Right Precinct
169 RT_SUBPRECINCT 2 2 C -   - RightSub-Precinct (Split)
171 RT_COUNTY_COMM 4 10 B -   - Right County Commissioner District
173 RT_STATE_HOUSE 4 10 B -   - Right State House District
175 RT_STATE_SENATE 4 10 B -   - Right State Senate District
177 RT_US_HOUSE 4 10 B -   - Right US House District
179 RT_POLICE_DIST 1 1 C -   - Right Police Patrol District