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Trinity River COMMON VISION Program

Digital Files and Contents
Trinity River Corridor Engineering Mapping

Contours

Topography - Digital 2-Foot Contours (CL)

The Trinity River Engineering Scale Mapping Database contains the most detailed contour mapping ever performed on a regional level in North Texas. Contours have been mapped to 2 foot intervals utilizing stereo compilation, and are in compliance with National Standards of Map Accuracy. All digital contours are closed and have been divided into 13 different categories, reflecting differences in elevation interval, visibility, and interaction from other structures.

Arc/Info Data Structure

Polygon Attribute File Structure

 DATAFILE NAME: CL.PAT                                              07/09/1996
    6 ITEMS: STARTING IN POSITION    1
 COL  ITEM NAME         WDTH OPUT TYP N.DEC  ALTERNATE NAME
    1  AREA                8   18  F    5
    9  PERIMETER           8   18  F    5
   17  CL#                 4    5  B    -
   21  CL-ID               4    5  B    -
   25  FEA_CODE            2    3  B    -
   27  ELEV                2    4  B    -

Sample Polygon Attribute File Contents

 $RECNO                 AREA          PERIMETER   CL# CL-ID FEA_CODE ELEV
      1    -34,999,998.65555       24,000.00000     1     0   0         0
      2     13,679,875.59377       19,545.05203     2     0  81         0
      3            145.31813           64.59594     3     1  81       467
      4        265,164.54808       24,058.11406     4     2  81       469
      5        255,170.73005       24,171.05544     5     3  81       467
      6        256,062.53010       23,937.38056     6     4  81       465
      7        312,058.97619       25,487.57939     7     5  81       465
      8        336,419.82954       26,768.41614     8     6  81       461
      9        284,453.62133       23,117.43371     9     7  81       459

Arc Attribute File Structure

 DATAFILE NAME: CL.AAT                                              07/09/1996
    9 ITEMS: STARTING IN POSITION    1
 COL  ITEM NAME         WDTH OPUT TYP N.DEC  ALTERNATE NAME  ANNOTATION
    1  FNODE#              4    5  B    -		     
    5  TNODE#              4    5  B    -	  	     Elevation 	1	
    9  LPOLY#              4    5  B    -
   13  RPOLY#              4    5  B    -
   17  LENGTH              8   18  F    5
   25  CL#                 4    5  B    -
   29  CL-ID               4    5  B    -
   33  FEA_CODE            2    3  B    -
   35  ELEV                2    4  B    -

Sample Arc Attribute File Contents

 $RECNO   FNODE# TNODE# LPOLY# RPOLY#             LENGTH   CL# CL-ID FEA_CODE ELEV
      1       2      1      3      1            25.55400     1     1  76      9999
      2       3      2      4      1            41.52367     2     2  76      9999
      3       4      3      5      1            57.82982     3     3  76      9999
      4       5      4      6      1            62.04282     4     4  76      9999
      5       6      5      7      1            76.03102     5     5  76      9999
      6       7      6      8      1            65.52953     6     6  76      9999
      7       8      7      9      1            55.94042     7     7  76      9999
      8       9      8     10      1            47.97103     8     8  76      9999
      9      10      9     11      1            45.80769     9     9  76      9999

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Feature Code Description
The codes listed below are the standards for features currently existing in the engineering mapping database. All of the features that have been mapped have been assigned a code. They should serve as a guide for understanding the data set and performing data analysis.

Contour Lines (CL) Arc Features

FEA_CODE : FEATURE DESCRIPTION

  • 66 Index Contour - Line identifying 10 foot contour interval.
  • 67 Index Contour Obscured - 10 foot Contour Line interpolated due to visual interference from other ground features/structures.
  • 68 Index Depression Contour - 10 foot Contour Line marking a depressed feature (sink hole, pit, etc...)
  • 69 Index Depression Obscured - 10 foot Contour Line marking a depressed feature interpolated due to visual interference.
  • 70 Intermediate Contour - Line identifying 2 foot contour interval.
  • 71 Intermediate Obscured - 2 foot Contour Line interpolated due to visual interference from other ground features/structures.
  • 72 Intermediate Depression - 2 foot Contour Line marking a depressed feature (sink hole, pit, etc...)
  • 73 Intermediate Depression Obscured - 2 foot Contour Line marking a depressed feature interpolated due to visual interference.
  • 74 Index Hidden - 10 foot Contour line through as obscuring structure such as a building or bridge.
  • 75 Intermediate Hidden - 2 foot Contour line through an obscuring structure such as a building or bridge.
  • 76 Contour Closure Line - Outer boundary line marking the extent of the digital information presently utilized. Closes off polygons that may or not extend into other data files.
  • 77 Index Contour (hidden text) - 10 foot Contours hidden by text placement.
  • 78 Intermediate Contour (hidden text) - 2 foot Contours hidden by text placement.

Contour Lines (CL) Polygon Features

FEA_CODE : FEATURE DESCRIPTION

  • 81 Area Label - Polygons representing areas located within a particular 2 foot contour interval.

 

 
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