﻿<?xml version="1.0" encoding="utf-8"?>
<gis_data_model>
  <feature_type name="Road Segment" geometry="LineString">
    <attributes>
      <attribute>
        <name>Road Name</name>
        <data_type>Text</data_type>
        <description>The name of the road that this road segment belongs to.</description>
        <nulls_allowed>Yes</nulls_allowed>
        <default_value>No Default Value</default_value>
      </attribute>
      <attribute>
        <name>Road Type</name>
        <data_type>Text (List of Values)</data_type>
        <description>The type of road. This value is from a list of acceptable values.</description>
        <nulls_allowed>No</nulls_allowed>
        <default_value>Urban Street</default_value>
      </attribute>
    </attributes>
    <policies>
      <creation_policy>
        <Paragraph>Road segments are created in three (3) primary ways. (1) Created from waypoints collected at the endpoints of the road segment and at key locations on the road segment. (2) Created from GPS tracks collected while traveling along the road segment. (3) Created from aerial photos, satellite photos, or public domain maps.</Paragraph>
        <Paragraph>If the first method is used to create a road segment, waypoints should be collected at road endpoints or intersections, at major angle points, and at the beginning and end of major curves. If the second method is used, the track sample rate/interval for urban streets should be set to no less than 25 feet. Other types of roads should not be sampled at less than 100 feet. If the third method is used to create a road segment the name and source of the image or map used to create the road segment geometry should be included in the metadata for the feature. (See the metadata policy for more information.) No minimum scale has been determined for images used for digitizing road segment geometry, but the geometry obtained should be comparable in precision to the geometry that can be obtained by handheld, recreation grade GPS receivers.</Paragraph>
      </creation_policy>
      <modification_policy />
      <destruction_policy />
      <metadata_policy />
    </policies>
    <relations>
      <related_spatial_features>
        <related_spatial_feature>
          <feature_type>Road Crossing</feature_type>
          <dependency_description>Road Crossing depends on Road Segment</dependency_description>
          <description>A Road Crossing feature located the point in which another linear feature (that is not a road) crosses a road segment.</description>
        </related_spatial_feature>
        <related_spatial_feature>
          <feature_type>Road Intersection</feature_type>
          <dependency_description>Road Intersection does not depend on Road Segment</dependency_description>
          <description>A Road Intersection feature is located at the point of intersection between two (2) or more Road Segment Features.</description>
        </related_spatial_feature>
        <related_spatial_feature>
          <feature_type>Road Terminus</feature_type>
          <dependency_description>Road Crossing depends on Road Segment</dependency_description>
          <description>A Road Terminus feature locates the terminus or end of a Road Segment. Road Terminus features are not placed at Road Intersection features, but at the location of a dead end or cul-de-sac.</description>
          <restrictions>
            <restriction type="Topology">
              <rule>A Road Terminus Feature must be located at the end point of a Road Segment feature.</rule>
            </restriction>
            <restriction type="Topology">
              <rule>A Road Terminus Feature must not be located at a road intersection feature.</rule>
            </restriction>
          </restrictions>
        </related_spatial_feature>
      </related_spatial_features>
      <related_non-spatial_features>
        <related_non-spatial_feature>
          <feature_type>Road Maintainer</feature_type>
          <dependency_description>Road Maintainer does not depend on Road Segment</dependency_description>
          <description>A Road Segment is maintained by an organization or entity known as a road maintainer.</description>
        </related_non-spatial_feature>
      </related_non-spatial_features>
      <related_temporal_features>
        <related_temporal_feature>
          <feature_type>Road Segment Constructed</feature_type>
          <temporal_type>Event</temporal_type>
          <dependency_description>Road Segment Constructed does depend on Road Segment</dependency_description>
          <description>A Road Segment is constructed.</description>
        </related_temporal_feature>
      </related_temporal_features>
    </relations>
  </feature_type>
</gis_data_model>