Utilizing GIS for Alignment, Right-of- Way Creation, Alignment Feature Creation and Maintenance

Transcription

1 Utilizing GIS for Alignment, Right-of- Way Creation, Alignment Feature Creation and Maintenance Yaneev Golombek GIS Specialist Merrick & Company June 12, 2007 Abstract Geographic Information Systems (GIS) is a key spatial database technology for effective and efficient creation of electronic railroad alignment and is an essential tool for both long term electronic railroad alignment maintenance and maintenance of features that impact an alignment right-of-way. This venture is based on ongoing efforts to convert a traditional hard-copy system into an electronic geo-spatial GIS system consisting of digital roll-maps and.pdf format license agreements and land leases. A chain of procedures can convert hardcopy alignment roll-maps into electronic GIS format that can easily be viewed, altered and shared for internal management purposes. The initial process includes scanning hard-copy roll maps into electronic format, digitizing roll-map alignment from aerial imagery and geo-rectifying a roll map s electronic image to a digitized alignment. Then, distancing features such as milepost and stationing markers are extracted and snapped to the traced alignment and the GIS is configured to provide milepost or stationing at any point on the alignment. Impacting features can be placed on the electronic alignment by inputting proper milepost or stationing into the GIS. Once these features are properly inputted on the alignment, a variety of attributes can be affiliated with each feature and viewed in the GIS. License agreement and land lease document files can be linked to their spatial location in the GIS and viewed. This entire GIS process gives the end-user a single electronic data depot to access all necessary information regarding an alignment or any features that may impact the alignment and allows for easy and effective long-term maintenance of the alignment and these features.

2 Table of Contents Introduction Creating Digital Alignment Integrating Distancing Dynamics into the Digital GIS Alignment Inputting Features and Attribute Information Hyperlinking Customized GIS Applications and Tools Benefits of Process Conclusion References

3 Introduction In the railroad industry, finding new innovative methods to digitally manage railroad alignments and features that impact alignments is a challenge. While a railroad company may have a records room filled with thousands of loose documents including license agreements, land leases, other impacting features and surveyed alignment roll maps, these documents may be decades old, unorganized, falling apart and hard to find. The challenge is making both the alignment roll maps and impacting features not only digital, but also spatially oriented, which is a task that fortunately can be done with Geographic Information Systems (GIS). Consider a few simple scenarios: A railroad company needs to reconstruct a section of its track or conduct construction at some part. Doing so will require providing all information on facility crossings of that section to a design firm so that they can plan accordingly. Is there a way to instantly provide spatially accurate data on that section? Another example: an accident occurs and chemicals leach into the ground. How can one easily and instantly produce spatially referenced maps of all underground facilities in that area to see if critical infrastructure will be affected? Yet another scenario: a railroad company is negotiating Right-of-Way (ROW) crossings with a utility company and would like to create a map that accurately displays all crossings with that company for management purposes. All of these scenarios, as well as dozens more can be accomplished by integrating alignment data and impacting features into a GIS database. GIS is a system of hardware and software used for storage, retrieval, mapping, and analysis of geographic data, specifically geographic data that can

4 1 be mapped out. GIS is a centralized data depot that brings together a variety of spatially referenced features and their associated databases to query, analyze, generate maps, and produce reports. A GIS database is durable yet flexible. As new data and features become available, the process of keeping the GIS updated is simple for anyone with basic database skills. This paper discusses ongoing efforts by Merrick & Company to convert a traditional hardcopy system including roll maps and thousands of Figure 1 paper documents consisting of license agreements and land leases into a single electronic and spatially referenced GIS system/database (see Figure 1). This process involves innovative use of existing ESRI GIS applications, particularly ArcMap, and developing customized GIS applications to work with ESRI GIS software. The end result of this process provides a single, centralized data depot for a user to access all necessary information regarding an alignment or any features that may impact the alignment and allows for easy and effective long-term maintenance of the alignment. Such a database is essential in creating a permanent, nondestructible archive of records. Additionally, such a system is essential for dealing with a variety of internal management, legal and design issues. Converting from Hard Copy to Digital In order to make this entire process work, hard copy roll maps, license agreements and land leases must all be converted to a digital format. Depending on the amount of hard copy data that exists, this process can be arduous, though if done properly, will provide a lasting archive.

5 This process can be simply carried out by utilizing two different scanners. The first is a high speed scanner that can instantly convert each individual license agreement or land lease into a.pdf file. Once each individual agreement or lease is scanned into its own.pdf, it is Figure 2 Scanning to.pdf important that some organization process is followed that gives each file its own systematic unique ID, and separates the.pdfs by some spatial reference, such as the city or town the feature exists near. The second scanner must be wide enough to accommodate the roll maps and have enough memory to process each one, as roll maps can be dozens of feet long. This scanner should save each roll map into a.tif file, which Figure 3 Map Scanner will later be utilized when importing the maps into the GIS. Once these two processes are complete, the initial process of making all records digital is complete. The steps below will deal with making the data geospatial, which opens doors to many advanced types of analysis and data management. Creating Digital Alignment The initial step in the GIS conversion process is to create digital alignment. The digital alignment must be created in a GIS compatible line-file such as a shapefile, or geodatabase feature class. There are a few ways that digital alignment can be created or traced. The two methods described below both require some form of aerial imagery.

6 The simpler way is to trace digital alignment of a railroad alignment if spatially referenced orthophotography is available. Orthophotography is digital imagery in which distortion from the camera angle and topography have been removed, thus equalizing the distances represented on the image. If orthophotography of a railroad alignment is available, a user can use GIS to digitize the track from spatially referenced orthophotography, providing a spatially accurate representation of the track. 2 Merrick Customized Railroad Applications Toolbar (discussed below) ESRI ArcMap Interface Digitized RR Alignment Figure 4 digitizing an alignment using geo-rectified orthophotography. However, orthophotography may not always be available. In these situations, it is best to utilize National Agriculture Imagery Program (NAIP) photography. NAIP photography is available via download from the US Department of Agriculture s website. Though NAIP photography is likely not as accurate as orthophotography, its accuracy is sufficient for the processes

7 described in this paper. Once the NAIP imagery is downloaded, it can be brought into GIS and the alignment can be traced/digitized from the NAIP imagery. Either one of these two methods will provide a digital and spatially accurate representation of the alignment. National Geographic topography maps can also be used to digitize alignment, though it is less accurate then the methods described above. Integrating Distancing Dynamics into the Digital GIS Alignment Once the digital alignment is created through GIS, the next step involves integrating distancing dynamics into the alignment. Since roll maps contain stationing and/or mileposts for all parts of a track, extracting this data and placing it on the alignment provides distance references. In order to do this, the surveyed roll maps must be geo-referenced, or matched up to the alignment. Since roll maps are often long and non-consistent due to match-line breaks, they must be broken up into several parts before they can be used. Adobe Photoshop is an adequate software package that permits a user to import these scanned maps and then break them up based on match-line breaks. Once the roll maps are broken out, the next step is to geo-reference them to the alignment. GIS software contains some routine tools for this process. This process involves matching known points on the roll-maps to known points on GIS layers. This generates control points to accurately spatially reference the roll maps to their true location in the GIS. Efforts with this have found that the best points to use for control are either township/range section corners or the points where the railroad alignment crosses sections. Therefore, a GIS layer of state sections must be available and placed on top of the alignment file.

8 Figure 5 The top image is a scanned roll map that is roughly 3 feet wide and 30 feet long. The maps have 7 match-line breaks. Adobe Photoshop is used to create individual maps based on the breaks. Section lines Digitized Alignment RR Alignment on Roll Map Section Lines on Roll Map Figure 6 After maps from the roll maps are broken out via match-line breaks, they are brought into the GIS for Georeferencing. Note the section lines that are used as control in the next figure.

9 Figure 7 As the section corners and points where alignment crosses sections are matched between the roll map and the digitized alignment, the roll map becomes georeferenced to the alignment. Once the georeferencing is complete, the altered roll map is saved to a separate file to create a permanent georeferenced archive that can be brought into the GIS as any time.

10 Figure 8 This exhibit is a group of georeferenced maps. The bottom map is the exhibit referenced in Figure 7.

11 Figure 9 - Zoomed in box from Figure 6. Once the roll maps are referenced to their true location in the GIS, the next step involves digitizing the distance markers, known as stationing and milepost points, from the roll maps onto the alignment. This is a simple process of dropping a point at the station or milepost on the roll map s hash marks and attributing each point that is dropped. For simplicity, stationing is dropped at every 1000 foot interval.

12 Digitized Stationing Digitized Milepost Figure 10 Stationing and Mileposts are digitized from the corresponding markers on the roll maps The process becomes more complex when there is inconsistent stationing or mileposts on the roll maps. To deal with this, Merrick has created an application that takes the initial known mile post or stationing and the last known mile post or stationing and systematically places them at their appropriate intervals along the line. If the initial or final distance marker is not known, then the marker is calculated from track charts (which contain distance markers), comparing a known feature on the roll map to the same feature on the track chart and then calculating the initial or final distance marker. In all cases, track charts are also used to check for accuracy of the automatically placed markers along a track. For example, see Figure 11. In this scenario, the ending milepost of an alignment is unknown. Object Q is present on both the roll map and the

13 track chart and the track chart indicates that the feature is somewhere between milepost 148 and 149. The track breaks mileposts into 1 inch intervals and the feature is 11/32 of an inch from milepost 148 and 21/32 of an inch from milepost 149. Simple calculations conclude that Milepost 148 must be placed 1815 feet east of the feature and milepost 149 is 3465 feet to the west of the object. The alignment actually ends 570 feet past milepost 149, so the western edge of the track is milepost Further QA/QC for accuracy on this alignment with the track chart concludes that all mileposts from start to end are accurate when placed via the automated tool. Since not every milepost in the railroad industry is Figure 11 The Process involve for creating an initial or ending milepost when one is not present on a roll map.

14 a 5280 foot segment of track, in these situations where mileposts don t exist on roll maps, matching known features on roll maps to track charts must be followed closely to assure no errors in milepost placement. Once all mileposts and stationing points are accurately placed on the GIS alignment, the next part is to make the line dynamic so that when features eventually get placed on the line, the GIS displays the milepost and stationing of that line (milepost to the nearest 100 th of a mile and stationing to the nearest foot). To do this, Merrick wrote an ESRI ArcInfo (ArcInfo is another ESRI GIS software) routine that takes the entire alignment and breaks apart the line to create multiple segments at milepost intervals. This routine then takes each milepost segment and calculates its starting and finishing stationing and then populates this information in the attribute table for each milepost segment. See Figure 12. The selected record is highlighted in its corresponding attribute table. Each mile segment record contains the starting and ending milepost and starting and ending stationing. The SHAPE_Length field on the right displays the number of feet in each segment. As previously mentioned, a milepost in the railroad industry is not always a 5280 foot segment. Sometimes there are long miles and sometime short miles. The SHAPE_Length field in the attribute table of Figure 12 displays diversity in milepost distances. Another issue with creating alignment is re-stationing equations. For a long alignment, it is common for stationing to end in the middle of an alignment and restart at a completely new and different set of stationing numbers. This often happens more than once on a single alignment. The solution for this type of a dilemma is to divide an alignment into several individual alignments based on stationing re-equation points. The alignment dynamics process described above

15 is then conducted on each individual stationing group. Once the process is complete for an entire alignment, the separated stationing groups are merged together to re-create a single alignment that consists of stationing equations where appropriate. Figure 12 Sample of how alignment milepost segments are broken apart with starting and finishing milepost and stationing. This process is crucial for the process of calculating milepost and stationing for any given point. In summary, the alignment distance dynamics process takes a single alignment segment of a track that can be anywhere from a few miles to hundreds of miles long, and ultimately creates segments at each mile interval that displays both mileposts and corresponding stationing at each milepost. This process is crucial for the next step which is actually placing features and corresponding feature data at accurate locations on the alignment. Additionally, this process creates point features for each milepost and 1000 foot stationing interval which is useful for a variety of displaying purposes.

16 Inputting Features and Attribute Information Once stationing and milepost distancing dynamics are created for alignments, the next step is to place impacting features and their corresponding attributes on the alignment. This process involves going back to the scanned.pdfs of license agreements, land leases or other impacting features and extracting that information into point features that get automatically placed on an alignment. To place impacting point features on an alignment, Merrick created a GIS application solely for this purpose that can work in several different ways, based on what distancing information is available on the feature s.pdf file. The simple way to place a feature is if the feature s milepost or stationing distance is known. If this is the case, then the application will allow a user to input the milepost and stationing and will automatically place the point on a selected alignment. Since the GIS performs calculations with the stationing, it gets entered in as a whole number without the + sign. Figure 13 Inputting a point on an alignment when milepost or stationing is known. Above is and example of a point entered by known stationing distance. If the milepost and stationing is not known, another component of this application allows the user to interactively place the point. A variety of street data and township/range section data can be overlaid in the GIS and matched to the

17 location on the feature s corresponding exhibit to provide a near accurate location of the feature s true location on the GIS. In this case, milepost and stationing is automatically calculated and attributed on the point. Figure 14 Entering Attribute information. Table contains 4 tabs and attributes can be custom designed for company needs. Once the location of the point is determined and placed via this application, the application will then display a window with several tabs to input attribute information (Figure 14). Once all information is added, the user closes out of the window and all entered information is placed in the feature s attribute table.

18 In cases where all information for a feature group is available in a spreadsheet format (for example, if a railroad had a spreadsheet of all culverts on an alignment with complete attribute information) Merrick also has an affiliated application that will allow a table format of that data to be entered. Then the application will place all that data on a selected alignment with all corresponding attributes attached to each feature. However, a stationing and/or milepost for each feature must be available if utilizing this process in order to place features. Merrick designed this alignment feature input application for ease of use and understanding. It permits any user with a limited knowledge of ESRI GIS products to be able to maintain an impacting feature database. Once features are added, their attributes can easily be changed and more features can easily be added or deleted as need be. Note that in the upper-right box of Figure 14, there is an entry for crossing fees and payment frequency. The ability to input that information in an attribute table allows a railroad company to track fees for ROW crossings inside the GIS. An individual managing this spatial database can simultaneously keep updated records and manage fee collection to parties that are obligated to pay for ROW crossing and eliminates the need for an individual to maintain a completely separate linear database dedicated to this task. Developing an easy to use application for this process is necessary for record management personnel to be able to actively maintain their ROW impacting feature database. Doing so allows updates to be consistent and prevents the database from becoming outdated and therefore maximizes the capability this system has for internal management of alignments and impacting feature crossings.

19 Figure 15 After attribute information is added, an info icon on ArcMap can display the attributes of any point.. Hyperlinking Another useful feature of the GIS is hyperlinking. Hyperlinks allow a user to access documents related to features using a hyperlink icon that is part of 3 ArcMap. If all feature documents (.pdfs in this case) are available at a single location on a hard drive or network, a user can establish an environmental variable to connect features displayed on the GIS to the document location. If done properly, a user can select the hyperlink icon, hover it over a feature on the alignment, click on the feature and open the document/.pdf affiliated with that feature.

20 Figure 16 Hyperlinking to a point and opening the corresponding document. Note the hyperlink icon on the toolbar. After clicking on it, a user can hover it over a point, click on the point and the relevant.pdf opens Customized GIS Applications and Tools To expedite an entire hard copy to digital GIS conversion process, Merrick & Company created a handful of ESRI GIS compatible applications. Some of these applications were discussed and displayed previously; however Figure 18 displays how the applications are laid out. The box at the top of Figure 18 displays the grouped tools in a railroad editor tool bar. The functions of these tools are as follows: Start Editing Opens up a unique editing section for inputting features on a railroad alignment. Save Edits Saves the edits once they are inputted.

21 Stop Editing Stops the edit session once edits are inputted and saved. Point Layer to Edit When a railroad feature point layer such as land leases or license agreements are brought into ArcMap, a user can select the layer in this box as a layer to input new features or edit pre-existing features. Alignment Layer to Edit Allows the user to select which alignment to add features to. For example if a user wanted to add license agreements to a specific alignment, both of those layers would be added to the ArcMap directory and selected in the Point Layer to Edit box and the Alignment Layer to Edit box, respectively. Make Point Using Distance See Figures 13 and 14 above. Make Point Interactively Allows a user to manually drop a feature on the line at the point of the features location. When this is done, milepost and stationing are automatically calculated and the window in Figure 14 appears for attribute input. Move Point Allows a user to interactively move a point to a different location. When doing this, new milepost and stationing is automatically calculated in the point s attributes. Edit Point Attributes When selecting this icon and then clicking on a feature, the window from Figure 14 will open pre-populated and a user can change and re-save the information. Calculate Values for Selected Points Calculates milepost and stationing of a point on an alignment.

22 Batch Processing This tool has two separate uses. One use is to take information about a feature that is in table or spreadsheet format (mentioned on page 16 and illustrated in Figure 17), utilize the stationing or milepost field place the points on an alignment and automatically populate attributes from the table to corresponding attributes once the points are placed. The other purpose as described in the Figure 17 The batch processing tool. Integrating Distance Dynamics section is to batch process milepost and stationing on an alignment. Though digitizing directly from geo-referenced roll maps is more accurate, utilizing this process is necessary in situations where distance markers do not exist. In these situations, the Batch Processing tool is designed to process a table of mileposts or stationing distances and place the points at proper intervals along the track.

23 Start Editing Save Edits Stop Editing Point Layer to Edit Alignment Layer to Edit Make Point Using Distance Make Point interactively Move Point Edit Point Attributes Batch Processing Calculate Values for Selected Points Figure 18 GIS tools and applications for alignment and feature creation. The boxed area shows how the tools sit on the ESRI ArcMap Interface. Benefits of Process This process has many short term and long term benefits. Though many of the benefits are apparent, its users constantly discover new benefits and ways to assist different departments of the organization. Some of these benefits include: Process Creates Tangible Asset Converting from a traditional hard-copy system to a digital GIS system is a benefit because it can provide a railroad company with a tangible asset that eliminates worries of another asset being destroyed. Similar to a homeowner that takes an equity loan to improve and increase the value of a home, investing in a GIS digital system to manage alignment and impacting features accomplishes the

24 same thing. It eliminates the need to rely on paper documents and replaces it with a robust and dynamic single data depot of information that can be accessed in its entirety by a few simple clicks of a mouse. Insurance Incentives This conversion process can provide incentives to reduce insurance rates. As companies tend to store hard copy records in a single location, there is a risk of a catastrophic event occurring and therefore having to reproduce those records. Once these records become digital, that risk becomes more managable. Additionally, having instant access to all records at a few clicks of a mouse can provide information that can minimize impact of infrastructure should a catastrophic event occur at some point along a track. Organization and Querying Capabilities Organizing documents with spatial reference are crucial in the railroad industry. Issues are always coming up that require immediate access to documents for internal management and legal issues, to name a few. When thousands of records are located in file cabinets, it is inevitable that files will be misplaced and lost. This entire process virtually eliminates that threat because all documents will not only be digital, but geo-spatially referenced. A user looking to access a document simply needs to query a few key fields, or by simply knowing the rough location of a feature, a user can simply select all features in an area, isolate the one of interest and then hyperlink to produce the relevant document. For example, a user (displayed in Figures 19 and 20 below) needs to find a 12 concrete sanitary pipe located in a specific city. To do this, the user selects all points in the city and then opens the attribute table. An Excel-like spreadsheet opens up and some

25 simple queries isolate the sanitary pipe and the hyperlink tool opens up a.pdf of the document. Easy Long-Term Maintenance The ArcMap GIS interface along with Merrick s custom tools and applications for this process allows for easy long-term maintenance of alignment and impacting features. Personnel that currently maintain a hard copy system can easily learn to maintain the system digitally in GIS as long as they have basic computer skills. Improved Field Verifications A railroad may be required to survey and/or field verify ROW crossings at a specific part of a track. This system permits an individual to easily print out spatially referenced data of all impacting features at that specific track area, which highly minimizes the time a crew needs to spend locating impacting features. Company Aesthetics Companies in industries today are faced with efforts to keep up with the times, particularly modern technological advances. This conversion effort and migration to GIS for alignment and document maintenance is surely a suitable method to do just that. Since document and alignment maintenance are significant components to any railroad company, these efforts provide significant technological advancement.

26 Select Figures 19 & 20 Selecting a variety of points (highlighted in blue) and then opening up their spreadsheet-like attribute table and querying the attributes to produce results.

27 Conclusion Converting a hard-copy roll map and document archive into a digital spatially oriented GIS system has many benefits. It assures that documents and roll maps will never become lost or destroyed. Also, this kind of system allows instant access to critical railroad data that a user can utilize for a variety of consulting purposes. Once in this format, the data can easily be queried to provide any kind of information a user would like to display, including spatially oriented maps that display many forms of data pertaining to an alignment s impacting features. There is an old quote that a picture is worth 1000 words. That quote is very relevant with this effort because being able to spatially reference data as opposed to relying on hard copy documents and maybe some miscellaneous spreadsheet does wonders for those in positions that manage a great deal of spatially oriented data. This GIS effort eliminates the need to rely on paper docum ents and replaces it with a system that is a robust and dynamic single data depot of information that can be accessed in its entirety by a few simple clicks of a mouse. A digital GIS system of railroad alignment and impacting features is a valuable tool for internal management, consulting and legal issues, to name a few. It is a kind of system where its users constantly discover new benefits and ways to assist different departments of the organization.

28 References 1. Northwest GIS Services (2007). GIS Definition. (6 June, 2007). 2 GIS Lounge (2007). Orhthophotography GIS Terminology. (6 June, 2007). 3. Environmental Science Research Institute (ESRI). ArcGIS Desktop Help Hyperlinking ArcGIS Version 9.1, 2007.