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Planimetric Features

Category Land Data Base lb_data
Name(s) .bridges .dams .hydro .plss .rails .streets
Description Select Planimetric Features
Type ArcInfo Library base_lib
   
Abstract The planimetric feature sets represent a collection of linear features that we usually see on reference maps and are extremely important to all GIS/mapping applications. Available planimetric feature data layers include Bridges, Dams, Streams/Shorelines, select Public Land Survey System Section Corners, Railroads, and Edge-of- Pavement features initially collected from April 1993 aerial photography.
   
Maintenance Selective updates to the original planimetric feature sets were made for areas where significant change occurred based upon April 1997 aerial photography. Maintenance of planimetric features data layers continues using the "Planimetric Feature Maintenance Application" developed in Arc Macro Language (AML) by ITSD. Year 2000 modifications corrected the feature creation/modification date field. Future plans include exploring the integration of field data collected by Engineering for maintenance and enhance the planimetric data layers.
   
Source Large-Scale GIS Data Base Development Project (1993) and Update Project (1997)
   
Agency/
Contact
Information Technology Services Department / mjohnson@ci.ann-arbor.mi.us
   
Accuracy National Map Accuracy Standards for 1"=100', 1:1200, 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 Update Project Area, 51.5 Square Miles
Format Double Precision Coverages with INFO attributes
Tiles 96 tiles measuring 4,000' by 6,000', ctiles
Count See Qualifications Table
   
Enumeration
Layer  Layer Coverage  Num  Num  Num   Num
 Name  Description  Name Arcs   Polygons  Points  Anno Subclass
.bridges Bridges/
Overpasses
brdg_cov 143 134 - -
.dams Water Impoundment Structures dams_cov 27 9 - -
.hydro Streams/
Shorelines
hydr_cov 3337 822 - name/70
.plss Section
Corners
plss_cov - - 56 -
.rails Railroads rail_cov 99 - - name/64
.streets Edge-of-
Pavement
pave_cov 5207 - - -
   
Qualifications The April 1993 black and white aerial photography used for the production of the planimetric feature sets has a photo scale of 1:15,840 or 1"=1,320' with 60% forward lap and 30% side lap on Agfa Pan 50 film. Control panels on the ground were used in the aerial mission flown at an altitude of 7,920 feet.

The April 1997 black and white aerial photography used for the production of the planimetric feature sets has a photo scale of 1:7,680 or 1"=640' with 55-65% forward lap and side lap on Kodak 2405 film. Airborne GPS technology along with control panels on the ground were used in the aerial mission flown at an altitude of 3,840 feet. Selective update minimized for funding necessary for the update of planimetric feature sets by focusing resources on areas of significant change between April 1993 and April 1997.

The 9"x9" contact prints of 1993 and 1997 aerial photography are on file at the Planning Department.

xxxx_COV.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 XXXX_
COV#
4 5 B -   * Polygon Internal ID
21 XXXX_
COV-ID
4 5 B -   - Polygon User Assignable ID
                 
25 XXXX_
ID
5 5 I -   - Bridge/Dams Layers Only
or                
25 KFEAT 4 6 B -   - Symbolization Code
30 LOCAL-ID 5 5 C -   - BMMP ID/
Bridge Layer Only

xxxx_COV.PAT - Point Attribute Table Definition and Content

Column Field Name Width Output Type N Dec Alt Name Indexed? Field Content
                 
1 AREA 8 18 F 5   - Point Area ?
9 PERIMETER 8 18 F 5   - PointPerimeter ?
17 PLSS_
COV#
4 5 B -   * Point Internal ID
21 PLSS_
COV-ID
4 5 B -   - Point User Assignable ID
                 
25 KFEAT 4 6 B -   - Symbolization Code

xxxx_COV.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 XXXX_
COV#
4 5 B -   * Arc Internal ID
29 XXXX_
COV-ID
4 5 B -   - Arc User Assignable ID
                 
33 KFEAT 4 6 B -   - Symbolization Code
37 UPDATE 8 10 D -   - Date Modified