Advanced Tiger Conversion (Coverage)
Summary
Converts a set of U.S. Census Bureau TIGER/Line files to a set of ArcInfo coverages.
Usage
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Advanced Tiger Conversion performs the following conversion and processing tasks:
- Converts TIGER\line files to coverages.
- Builds output coverages for line, polygon, and point.
Once the Advanced Tiger Conversion converts your data, it begins to process the output coverages. It merges the polygon points with line features by combining features from the output line and area coverage with the output area point coverage, then builds line and polygon topology for the merged coverage.
TIGER data is normally topologically correct but can contain intersection errors. An intersection error occurs when two line features overlap without intersecting at a node, usually because the shape record that defines the shape of the line feature is missing. The ensuing two-point arc may cross over features that the shaped arc would not.
Polygon topology must be present to fully process TIGER data. If an intersection error is detected when topology is being built, polygon topology will not be created, and the tool will issue a message and stop processing.
- Merges line features and creates polygon labels.
- Provides handling of intersection errors.
- Copies and relates attribute tables to feature attributes.
- Optionally joins TIGER attributes to feature attribute tables.
The Join attributes option will join the basic line, area, and landmark point features to their feature attribute tables. This makes display and query easier and is recommended for simple applications.
TIGER data contains very large attribute tables that can sometimes slow down ArcInfo processes.
- Optionally projects to either UTM or State Plane coordinate systems.
You can specify either UTM or State Plane coordinate systems for your output coverages. If this option is not used, the projection for each coverage will be defined as Geographic. The tool will define the datum using the version number read from the TIGER/Line file. Datasets earlier than 1995 are in NAD27, and those released in 1995 or later are in NAD83 with the exception of Hawaii, which is only in NAD27.
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Converts all versions released after April 1989.
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Starting in 2007, the U.S. Census Bureau switched to a shapefile based format. Use the Feature_Class_To_Coverage tool on these.
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This tool does not support Record Types F and G released with the 1992 School District version. These are temporary record types, not found in earlier or subsequent versions.
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The output coverages created in the TIGER file conversion will always be in double precision. TIGER/Line files often contain tiny line segments that would be lost if converted to single precision.
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Advanced Tiger Conversion creates up to three output coverages. An ouput point coverage and an output landmark coverage are only created when the dataset contains area point and landmark features.
Syntax
| Parameter | Explanation | Data Type |
in_tiger_file_prefix |
The filename prefix, common to all files in the set of TIGER/Line files being converted. The prefix may include a directory pathname. | String |
out_cover_prefix |
The prefix of the output coverages to be created from the TIGER/Line files. | String |
join_attributes (Optional) |
Determines if the basic line, area, and landmark point features will be joined to their feature attribute tables.
| Boolean |
projection (Optional) |
The spatial reference of the output coverages.
| String |
zone_number (Optional) |
The zone number of the specified coordinate system. | Long |
tiger_version (Optional) |
The input TIGER/Line files version.
| String |
restart (Optional) |
Determines whether processing will continue if the TIGER data contains intersection errors.
| Boolean |
Code Sample
The following stand-alone script demonstrates how to import a set of TIGER/Line files to a set of coverages.
# Name: TigerTool_Example.py
# Description: Imports coverages from TIGER/Line files
# Requirements: ArcInfo Workstation
# Author: ESRI
# Import system modules
import arcpy
from arcpy import env
# Set environment settings
env.workspace = "C:/data"
# Set local variables
inTigerFilePrefix = "tgr23005.bw"
outCoverPrefix = "C:/output/bla23005"
joinAttributes = "NO_JOIN"
tigerVersion = 1995
# Execute TigerTool
arcpy.TigerTool_arc(inTigerFilePrefix, outCoverPrefix, joinAttributes, "",
"", tigerVersion, "")