Linear References tab - HxGN EAM - Version 11.07.01 - Feature Briefs - Hexagon

Use the Linear References tab of the equipment screens to define features of the linear equipment and their location.

See below for important attributes of the equipment screens that make the equipment linear:

• Type - System Codes Types entity LRTP.

  There are four different types:

  • Linear Reference System - To define features of a general nature, but ideally used for repeating or recurring features like distance markers or segmentation along the linear equipment. Features of this type can themselves be used as a reference to define the location of other linear references, like points of interest. For example, the old oak tree is located 50 feet north of milepost 8.

  • Point of Interest - To define features of a general nature, but ideally used for things that are unique and are not frequently repeated, such as a welcome center on a highway.

  • Related Equipment - To define the relationship with any other equipment, either a point equipment like a utility access hole, bus stop, or traffic light or a linear equipment like a parallel road, a culvert or a bridge crossing.

  • Related Part - To define the relationship with a part, such as ties, gravel, communication cable etc., that is used in or around the linear equipment.

• Class - Group your linear reference records by class. Later, this classification will be important to group the features for display on the graphical linear overview. Create a class for Entity LREF (Linear References).

  Consider the following examples:

  • You have a road that is 15 miles long and is named Kennedy Highway for the first 10 miles and from thereon is called Highway 14. This requires two linear reference records. The first record from 0 to 10 and the second from 10 to 15. The system knows these records belong together, and the graphical linear overview will display them next to each other if you assign the same Class to both records. For this example, it makes sense to call the Class Name, but you are free to use any description you like.

  • Your rail track is 5 miles long. The first 3 miles use wooden ties then 1 mile of concrete followed by the last mile of steel. You have these defined as parts (P1, 2, and 3). This time you create three records (Type is Related Part): P1 from 0 to 3, P2 from 3 to 4 and P3 from 4 to 5. You can group them together using a class called Ties.

• Equipment - Can only be entered if Type is Related Equipment.

• Part - Can only be entered if Type is Related Part.

• Condition - Can only be entered if the selected part is tracked by condition.

• Reference Description - Free description of the feature. This field will be available on most screens where you can define the location of the linear work, linear inspection, etc.

• From Point - Starting point of the feature. This must fall between the From Point (=Equipment Starting Point) and the Equipment Starting Point plus the defined Equipment Length as stated in the top section above the grid on this tab.
  But there is one exception to this rule. If you are referencing equipment and the referenced equipment is linear, you may choose a From Point that starts before the header equipment. Since the relative start of any linear equipment is always 0 that means you can enter a negative From Point in this case. The image below shows a child that is 14000 feet long. The parent is only 10000 feet long. The first 2000 feet of the child are not located on the parent, hence the negative From Point of the child on the parent.

  Make sure you do not confuse the from points on this screen. The From Point in the top is the starting point of the header equipment. The From Point you are populating here is the starting point of a linear reference feature like a milepost, a signal, etc. that is located along the linear header equipment.

• From Reference - Reference to another feature along the linear equipment. This feature must be of Type Linear Reference System, for example a milepost. Once you enter this field the system will also overwrite the From Point with the corresponding value. After entering a From Reference, you can also specify:

• From Offset - The distance of the feature to the selected From Reference. Once you enter this field the system will also apply this distance to the From Point immediately.

• From Offset Percentage - You can also use a percentage to estimate this distance. If a feature is located about halfway between two mileposts and you measure position in feet, then when you enter 50% here, the system will calculate an offset of 50% of the distance between these two mileposts. Normally, if the mileposts are placed perfectly, that would be 50% of 5280 feet is 2640. If you enter 10%, this would be 528.

• From Offset Direction - Since the offset is always a positive number, you still need the ability to specify the location of the feature as it relates to the selected From Reference. Is it 25 feet before or after the milepost? If the linear equipment Direction is north and the From Offset Direction is also north, then the feature is located after the milepost, providing that your look at the world, starts at the beginning. So, if the milepost is located at 5290 feet, 25 feet north would locate the feature at 5315 feet. Changes to this field will impact the From Point immediately.

  These additional fields help identify the location of the feature:

  • From X Coordinate

  • From Y Coordinate

  • From Latitude

  • From Longitude

• To Point - End (point) of the feature. This must fall between the Equipment Starting Point and the defined equipment length plus the Equipment Starting Point and must also be equal or greater than the From Point.
  The same exception for linear equipment as described for the From Point applies here.

  Additional fields to help identify the end point of the feature that function and serve a similar purpose as those fields for the starting point are:

  • To Offset

  • To Offset Percentage

  • To Offset Direction

  • To X Coordinate

  • To Y Coordinate

  • To Latitude

  • To Longitude

• Point Reference - Most features have no length. For example, a milepost or a signal. In that case, the From and To values should be the same. If you select Point Reference, the system will automatically make the To side equal to the From side.

• Date Effective - Date the record becomes effective or active. Date Effective and Date Expired are used to track the historical changes to the features of the linear equipment. From 1961 to 2008 the track used wooden ties, but since 2009 the ties are steel. The speed limit was 60 mph until 2010, after which it was increased to 65 mph.

• Date Expired - Date the record becomes in active.

• Geographical Reference - Optional alternative description of the feature. This field will be available on most screens where you can define the location of the linear work, linear inspection, etc.

• Inspection Direction - See above.

• Flow - See above.

• Apply to Children - If selected, this makes the record appear on the linear references tab of the children. This way bus stops, or traffic signals only must be defined one time on the parent record. To place the feature correctly on the child record, the relationship between the parent and the child needs to be clearly defined on the Linear References, Segments or Routes tab and in the equipment structure.

  The bus stop of the parent at 3,000 feet will display on the child at 5,000 feet. The traffic light at 8,000 will display on the child at 10,000 feet. This is consistent with the child being offset -2,000 before the parent. Linear reference records displayed this way on a child cannot be changed on that child equipment. You can recognize these "foreign" records because Source Type, Source Code and Source Org. will be populated.

• Apply to Route/ROW - If selected, this makes the record appear on the linear references tab of the parent route or right of way. It is the opposite function of the Apply to Children checkbox. Note that Apply to Route/ROW only works for the relationships between the three linear equipment types (Right of Way, Route and Segment). This way bus stops, or traffic signals only must be defined one time on the child record. To place the feature correctly on the parent record, the relationship between the parent and the child needs to be clearly defined on the Segments or Routes tab, but there is no need to also define it in the equipment structure.

• Repeat Every Length - Certain features appear more than once on a linear equipment, like distance markers, utility access holes, etc. To ease data entry, use the build in repeat feature. Enter a distance and select the appropriate unit of measure for Repeat Every Length. When you save the record, the system will create a set of duplicate records but with a different From Point and To Point based on the selected distance for Repeat Every Length. The set consists of as many copies that fit in the remaining length of the equipment. If the equipment is 5,000 feet long, the From Point is 1,500 feet long, and Repeat Every Length is 1,000 feet long, the system will generate 4 records in the set. One at 1,500, 2,500, 3,500 and 4,500 feet.

• Starting Sequence - You can enter the Sequence number for the first record the system saves. Leave this blank to start with 1 (one).

• Sequence - System assigned sequence number

• Set ID - System assigned identification number. All records that belong to the same set will have the same identification. The system uses the Set ID for updates and deletes. The system will ask if an update or deletion is also applicable for all consecutive records in the same set. Updates to Repeat Every Length are included in this capability. The system will delete and recreate the records based on the new distance selected.

  If you clear Repeat Every Length in update mode, the system will ask if you want to remove the record from the set. Once removed it cannot be added back again.

• Display on Overview - Select this to view the record on the Linear Overview.

  Even if selected, Class must also be populated for the record to become visible on the Linear Overview.

• Color - The color of the bar on the Linear Overview. For example, you can specify brown for wooden ties and blue for steel. If no color is specified, the system will use defaults.

• Icon - The icon displayed in the bar on the Linear Overview. If no icon is selected the system uses the icon associated to the Class. First the Class of the linear reference record and then the Class of the equipment or Part.

• Icon Path - If you fill in Other in Icon this field becomes unprotected, and you can pick your own icon for display. Ideally the size of these icons is 16 by 16 pixels.

• Relationship Type - System Codes entity "RETP." Relationships are user defined, for example parallel, perpendicular, crossing, overpass, etc.

• Horizontal Offset - Horizontal distance to the linear equipment. The bus stop could be 6 feet away from the edge of the road.

• Horizontal Offset Type - System Codes entity "OFTP," System Codes "H" (Horizontal types) and "*" (All types). Offset types are user defined, for example North, South, East, West, Right from centerline, From right, etc.

• Vertical Offset - Vertical distance to the linear equipment. The traffic light could be hanging 18 feet above the road.

• Vertical Offset Type - System Codes entity "OFTP," System Codes "V" (Vertical types) and "*" (All types). Offset types are user defined, for example Above, Below, etc.

• Qty. per UOM - You can specify an amount per distance UOM. Enter 1 meter if you have 1 tie per every one meter.

• Width - You can specify a width. Enter 6 feet if the gravel path is 6 feet wide.

• Height - You can specify a height. Enter ½ feet if the gravel layer on the path is 6 inches deep.

Buttons

• Split - You can split a selected linear reference record into two parts. Originally for the complete length of 12 miles the speed was 60 mph. After January 1st however, the last 4 miles will be 65 mph. On the Split Linear Reference popup enter:

• Date Effective - Date the change takes or took effect. January 1st.

• Split point - Distance where the break will occur. Enter 8 miles.

• Description Segment 1 - This defaults and remains 60 mph.

• Description Segment 2 - This defaults to 60 mph. Change it to 65 mph.

• Insert Inside - You can split a selected linear reference record into three parts. Originally for the complete length of 12 miles the road surface was dirt. After January 1st however, mile 4, 5 and 6 will be gravel. On the Insert Linear Reference Inside popup enter:

• Date Effective - Date the change takes or took effect. January 1st.

• From Point - Starting point of the new segment. Enter 4 miles.

• To Point - Ending point of the new segment. Enter 7 miles.

• Description - This defaults to Dirt. Change it to Gravel.

  Both buttons will update the selected linear reference record and set the Date Expired equal to the day before the entered Date Effective. Then they will create new records (2 for a split, 3 for an insert inside) to represent the new situation effective on the Date Effective.

• Custom Fields - You can enter Custom Field values for each linear reference record, as required. Custom Fields are controlled by the entity "LREF" and the linear reference Class that you selected for the record.