Geospatial Data Standards

Transcription

1 Geospatial Data Standards Prepared For: Town of Morrisville, NC Prepared By: Joshua Knight Senior Geospatial Consultant Version 2: November 14, 2017 Version FINAL: April 30, 2018 Page 1

2 Contents Section 1 Introduction Scope... 3 Section 2 Roles and Responsibilities Management Author/Creator Administration... 6 Section 3 GIS Data Collection Standards GPS Data Collection and Delivery GPS/GNSS Concepts Field Data Collection Parameters Data Dictionaries Processing of GPS Field Data Reference Networks and GPS Post Processing Output to GIS Elevation Data Naming Convention Deliverables Project Report Section 4 GIS Data Standards... Error! Bookmark not defined Spatial Reference Data Creation and Collection Accuracy Requirements Supported Data Formats GIS Data Matrix Metadata for GIS and GPS Data Section 5 - Data Compilation Goals.21 Page 2

3 Section 1 Introduction The Town of Morrisville (Town) has developed a Geographic Information System (GIS) for the storage and analysis of geospatial data and related information. In order to improve the effectiveness of the Town s GIS, it is necessary to develop and implement standards that provide clear instructions about who will manage geospatial data, procedures for collecting data in the field, and how that data will be maintained within the system Scope The following document is comprised of five sections, each one covering a specific task necessary to create a comprehensive Geospatial Data Standards document. Section 1: The first section will cover Introduction and Scope of the document. Section 2: The second section will cover Roles and Responsibilities. The purpose here is to provide descriptions of Roles within a GIS, and examples of duties that an individual could be responsible for performing. Section 3: The third section will cover GIS Data Collection Standards. The purpose here is to provide instructions for capturing data in the field, and submitting the same data back to the Town for use in its GIS. Section 4: The fourth section will cover GIS Data Standards. The purpose here is to describe how spatial data should be managed within the Town s GIS. Section 5: The fifth section will cover Data Compilation Goals. The purpose here is suggest how the Town can organize its internal procedures and workflows to support an enterprise GIS. Page 3

4 Section 2 Roles and Responsibilities Based off research into industry best management practices for local government organizations implementing a GIS, there are essentially three primary roles found within a GIS (along with examples of responsibilities for each). These examples are meant to be indicative of what is expected in these roles, but by no means are a complete definition of all tasks. Every GIS department is organized differently, the roles described below are not recommendations for the Town. Management Develops long term and strategic objectives for the GIS Author/Creator Utilizes GIS software to create and share data and analysis from GIS Administration Responsible for software design and administration of GIS databases Management GIS Manager A GIS Manager develops medium and long term goals for the GIS Division in order to support system objectives. This person has advanced knowledge of GIS planning, implementation, and requirements. This role may include, but is not limited to: Day-to-day management of GIS projects, staff, and budget May also work with the Database Administrator (DBA) and Coordinator in the creation of GIS databases, and work with other managers to support initiatives across the entire organization GIS Project Manager/Coordinator A GIS Project Manager/Coordinator plans, organizes, coordinates, and participates in the development and implementation of the Town GIS to meet the organization s mapping and end-user service objectives. They provide expertise, support, assistance, and guidance to staff and external contacts. A GIS Project Manager/Coordinator s responsibilities may include, but is not limited to: Page 4

5 Working closely with Data Owners to identify GIS requirements, technical issues, and training needs Analyzing current business processes and recommending best-practice solutions Communicating with internal and external technical resources to resolve end-user issues and providing guidance to users on methods for correcting reported problems Author/Creator Subject Matter Expert (SME) A Subject Matter Expert is an acknowledged expert in the practical areas of GIS, and the point of contact for Management to work with. Responsible for data integrity and the releasing of updates to the system, a Subject Matter Expert s responsibilities may also include, but is not limited to: Point of Contact for the department providing the data to the system Works with Administration on creating new applications and databases for storing their department s data. Understands their department s workflow and the data available Monitors and corrects any data imported into GIS from vendors, internal sources, and field data May suggest updates to GIS and GPS Data Standards, and also provide training and best management practices to support staff on maintaining compliance with standards GIS Analyst A GIS Analyst has specific knowledge of the computer operating systems, GIS software applications, GIS concepts, and database/application design principles. An analyst requires an advanced understanding of geospatial data and analysis, along with functions and tasks that GIS applications will support. A GIS Analyst's responsibilities may include, but is not limited to: Conducting use-case analysis of business functions to establish GIS application requirements and geospatial data model requirements Identifying and defining appropriate applications of the system and associated GIS products Planning and designing the analytic procedures and methodologies for performing the applications Conducting in-house training and tracking progress on system implementation and application projects Planning and communicating specific work tasks for database creation and management, application development and ongoing maintenance Page 5

6 Data Editor A data editor has specific knowledge to create and maintain their department's geographic data by importing and processing data from other sources. A data editor possesses geocoding and linear referencing skills that involve data compilation and editing to build significant portions of their GIS datasets. They apply tools and techniques that help ensure data integrity during editing. A Data Editor s responsibilities may include, but is not limited to: Accurately creating and maintaining data stored in a geodatabase that is used to produce GIS maps and analysis results that support informed decision making Assigning locations to other data sets for mobile clients and applying a standard editing workflow to support accurate field data collection and updates to the GIS database Efficiently creating and editing feature geometry and attributes and solve common data alignment issues Digitizing and editing geographic features to maintain spatial relationships using topology Compiling and integrating map data for automation from diverse sources such as existing maps, aerial photography and satellite imagery Solving problems related to the registration of different map layers Designing high-quality map and graphic products for output by the GIS system Administration System Administrator A System Administrator maintains hardware, software, telecommunications, peripherals, and associated components. This individual must be familiar with GIS operations, how they differ from other IT systems, and how differences affect system usage and administration. Due to the interdependencies between GIS and non-gis computer hardware systems, coordination with administrators of non-gis systems is critical. A System Administrator s responsibilities may include, but is not limited to: Analyzing, troubleshooting, and resolving GIS application problems Analyzing current GIS system functions, procedures, and capabilities to determine if improved methods are possible, and develop proposals for new approaches or options to meet user needs Database Administrator (DBA) The database administrator has primary responsibility for the spatial and tabular databases of the GIS. A Database Administrator s responsibilities may include, but is not limited to: Page 6

7 Oversees data automation and maintenance and is involved in logical, detailed database design and the design and maintenance of standards related to data entry and updating The database administrator works with users to implement data standards and quality assurance programs by creating and updating the data dictionary and automated data validation functions. Monitors and corrects any data imported into GIS from vendors, internal sources, and field data. Performs extensive testing on applications developed internally or purchased from vendors Web Developer The Web Developer creates and deploys an organization's GIS functionality over the web and requires a firm understanding of the impacts and security implications of maintaining and operating a GIS. This individual usually works closely with Application Developer. This role is often combined with the System Administrator role. Application Developer The application developer creates custom applications to meet specific user needs, ranging from spatial data conversion programs to interface designs that support inexperienced users. This may include, but is not limited to: Analyzing, troubleshooting, and resolving GIS application problems Quality Control (QA/QC) Has responsibility for data integrity and application testing to ensure quality information is input into GIS by enforcing GIS and GPS Data Standards. Will review data and applications created by Editors, Analysts, and Developers to ensure the highest and best accuracy possible. This may include, but is not limited to: Monitors and corrects any data imported into GIS from vendors, internal sources, and field data. Performs extensive testing on applications developed internally or purchased from vendors May suggest updates to GIS and GPS Data Standards, and also provide training and best management practices to support staff on maintaining compliance with these standards Page 7

8 Section 3 Global Positioning System (GPS) Data Collection Standards The following standards are not to be used in lieu of minimum requirements set by NC Board of Examiners for Engineers and Land Surveyors when data collection activities fall within the definition of the "practice of land surveying" as defined by The North Carolina Engineering and Surveying Act (G.S. 89C-3.7). This means that any spatial data collected by internal staff and external vendors/contractors, should only be for the purpose of collecting data for use within the Town s GIS. The use of the Global Navigation Satellite Systems (GNSS) and Terrestrial Positioning Systems (TPS) for accurately locating real world features and attributes has become a widely accepted method for collecting GIS data. The following GIS Data Collection Standards do not define threshold accuracy values or minimum positional accuracy required for a given GIS feature. That information should be defined in the GIS Data Matrix document, and will be determined by the GIS Manager (or representative) on a project by project basis GPS Data Collection and Delivery GPS/GNSS receivers allow users to collect the locations in real world coordinates. For the purposes of this document, GPS and GNSS should be considered to mean the same thing GPS/GNSS Concepts GPS is the United States constellation of satellites, which was the first to become usable. Since the GPS constellation was deployed, several other satellite constellations have also been deployed including the Russian Glonass, European Union Galileo and Chinese Beidou. Many newer model receivers can be configured to receive signals from one or more of these constellations. This can increase accuracy and reduce the time needed to occupy a location. All of these constellations are now referred to collectively as Global Navigation Satellite Systems or GNSS. The vertical accuracy of any GNSS receiver is typically equal to one and a half to two times its horizontal accuracy. To achieve reliable vertical accuracies, regardless of the type of GNSS receiver being used, the antenna must be mounted on a pole or similar device which allows the user to measure, maintain, and record a consistent antenna height. To ensure that the appropriate type of GNSS receiver is matched to the mapping application, an understanding of receiver capabilities and limitations is required. For most applications, there are three types of GNSS receivers: Recreational Grade (Low Accuracy) These units have a typical average horizontal accuracy of fifteen to sixty feet, with limited to no information about the quality of position displayed or collected on Page 8

9 the unit. They normally do not have the ability to "post-process" field data that is collected or utilize real time corrections for improving positional accuracy. Recreational GNSS receivers can basically only be used to navigate to a general area. Smart phones and tablets are a good example of recreational GNSS. Mapping/GIS Grade (Medium Accuracy) These units have a typical average horizontal accuracy that ranges from four inches (4 ) to fifteen feet (15 ). They also have the ability to log raw GNSS data (allowing desktop software to Post Process and improve positional accuracy dramatically). This category of GNSS receiver also has the ability to communicate with a reference network (Real Time Corrections), store attributes of features, use a data dictionary, and transfer data from the GNSS device to a personal computer (PC) in a GIS compatible format. Units such as a Trimble Geo or Leica Zeno 20 are good examples of this type GNSS receiver. There are also several external smart antennas on the market which can be paired with other devices such as tablets or smart phones. This will increase the accuracy of those units turning them into a GIS or higher grade receiver. Survey Grade (High Accuracy) These units can achieve sub-centimeter level accuracy, and are traditionally used by land surveyors for projects like boundary, topographic, or geodetic surveys. They have the ability to both post process data collected at a later date, or connect to a Reference Networks for real time corrections Minimum GPS Receiver Requirements Any GPS receiver used to collect data for the Town has to be Mapping/GIS Grade quality or better, and must: Routinely achieve one (1) meter or better horizontal accuracy, using either real time or post processed differential corrections. Operate in a 3D mode, where the receiver requires signals from a minimum of five satellites to determine fixed position. When mapping real world features, the receiver must be able to collect and store multiple positions (the minimum number depending on the quality required for that particular feature). Must also have enough internal storage capacity for a typical day s worth of data without the need to transfer to PC. Configurable for user settings like GDOP (geometric dilution of precision), (positional dilution of precision) PDOP, elevation mask, and logging rate. Be able to utilize existing GIS data for base map, and export in a compatible format for enterprise GIS from unit or desktop software (geodatabase or shapefile). Page 9

10 3.4 - Field Data Collection Parameters Staff or outside contractors should have a thorough understanding of basic GPS concepts and receiver operations. They must also have familiarity with the types of features that are to be located, and able to recognize/interpret features in the field. To achieve target accuracy all collected GPS data must be differentially corrected, either in real time or in a post process step. The Town requires checking into at least one known point before beginning data collection, and one after. This field procedure helps ensure the correct reference base station is being used, and that obstructions and satellite positions are optimal for accuracy. Position Mode: All position fixes must be determined with 5 or more satellites. Manual 3D or overdetermined 3D (5 satellites minimum) modes are acceptable. 2D fixes (using only 3 satellites) are not acceptable. 3D positions generated from 2D fixes supplemented with user entered elevations are also not acceptable. The following other minimum settings or conditions must also be maintained for all collected locations: 1. Elevation Mask: 15 degrees above horizon. 2. PDOP Mask: Max PDOP = Minimum Positions: Set to achieve minimum level of accuracy accepted (1 meter), unless granted a different requirement by the Town s GIS Division. 4. Logging Intervals (Epochs): Intervals for features will be at least 3-5 seconds, with line and area features accuracy depending on the velocity at which the receiver is traveling and the nature of the feature and obstructions present. 5. 3D Coordinate Quality: This parameter setting will be set to allow the logging of coordinate values along with position fixes for data collected Data Dictionaries A data dictionary is a list of attributes to be collected, the field characteristics for each attribute and acceptable values (if appropriate). If a data dictionary exists for a GIS feature, the Town requires that it be used for data collection. This will ensure that data collected will be compatible with existing data in the GIS. These may be requested from the Town by contacting the GIS Division Processing of GPS Field Data All GPS data collected for the Town must either be captured with the real-time kinematic (RTK) method using the NC GNSS Real Time Network, or post processed using desktop software before the data can be used in the GIS. The GNSS processing software must be able to download GNSS data files from the GNSS receiver, and perform differential corrections. In addition, it must allow exporting the corrected data to a compatible format Page 10

11 (ESRI File Geodatabase, Personal Geodatabase, or Shapefile) used by the Town, in the North Carolina state plane coordinate system. Refer to the section below for specific information on the required coordinate system Reference Networks and GPS Post Processing For Reference Network Corrections, several resources exist in North Carolina such as the NC GNSS Real Time Network. For post processed differential corrections, several resources exist for GPS base station data in North Carolina such as National Geodetic Survey Online Positioning User Service (OPUS) Output to GIS The Town uses ESRI software and requires GIS data submittals to be in ESRI File Geodatabase (.gdb), Personal Geodatabase (.mdb), or Shapefile format (.shp). The GNSS software must allow for exporting to one of these formats. In addition to feature coordinate and field entered attribute data, the GNSS software used should be capable of generating attribute information for exported features. This information will include data about the quality of the GPS position fixes that were used to generate the features. At a minimum, the following attributes must be produced for exported features, and if it is not automatically generated by the GNSS software it must be manually entered: Point Features o Maximum PDOP o Receiver type o Date of collection o Time of collection o Data file name o Total positions o Positional Accuracy 2D or 3D o Orthometric Height o Vertical Accuracy o Antenna Height Line and Polygon Features o Maximum PDOP o Receiver type o Date of collection o Time of collection o Data file name o Total positions Page 11

12 o Worst horizontal precision o Average vertical precision o Worst vertical precision o Antenna Height Elevation Data If the collection of accurate elevation data is required as part of a project, it will be referenced to the North American Vertical Datum of 1988 (NAVD 88) vertical geodetic datum. Elevations must be generated as orthometric heights (relative to mean sea level) determined using GEOID99 model (Continental US). Data must be collected with a Survey Grade GNSS receiver when elevational or vertical data is required as part of a project. To achieve reliable vertical accuracies, regardless of the type of GNSS receiver being used, the antenna must be mounted on a pole or similar device which allows the user to measure, maintain, and record a consistent antenna height Naming Conventions It is important that GNSS data and attribute field names be delivered to the Town follow the same structure already created for existing data (unless it s a new feature type). Not all of the following rules may apply to all datasets, but it s important to understand the geospatial naming convention already in place to resolve any conflict that might arise on import of delivered data into the GIS. No leading numbers or special characters. Do not include spaces, dashes, underscores or other special characters Do not use prefix or suffix for data type Do not use geometry type as suffix Avoid using reserved words (ADD ALTER AND AS ASC BETWEEN BY COLUMN) Limit names to 10 characters or less (Shapefile only) Always provide alias names for attribute fields Always submit GIS/spatial data with correct projection definition (NCCS) File Version Control Other Naming Conventions? Directory/subdirectory Naming conventions? Page 12

13 Deliverables If GNSS data collection work is being performed by an outside agency, final deliverables shall meet the minimum requirements as set forth by the Town, including: All GNSS field data files, both uncorrected and corrected versions, must be submitted. If field data was collected in real time differential mode, then there will not be uncorrected files, and only the real time corrected files are necessary. If edits are made to corrected files (i.e., fixes deleted or offset), copies of both edited and unedited are to be submitted. All GNSS to GIS export files, using North Carolina State Plane Coordinates, in the NAD 83 (2011) horizontal geodetic datum, in US survey feet units, in Esri File Geodatabase, Personal Geodatabase, or Shapefile. All GNSS processing log files pertaining to post process differential correction and GIS export (if produced by the GNSS processing software). GPS Data dictionary files, defined for project attribute storage. Metadata Project Report The contractor or vendor must submit a project report that includes the following information. An introduction describing the project. Include the project name, the names of Town departments involved/supported, the purpose and goals of the project, the project s study area, and data collection (including accuracy) requirements. Reference Network or GPS base stations used for the project. If local base stations (stations other than Reference Network) were used, the setup procedure must be described in detail, along with then operation, collection parameter settings, and what steps were used to establish the reference position. These files should all be in a compressed format and be organized into a logical directory structure. For example, the files could be organized by date of data collection, and then into subdirectories for Data and Export. Uncorrected, corrected field data files, post process differential correction log files, and data dictionary files would reside in the Data subdirectory. GIS export files and associated export log files would reside in the Export subdirectory. Page 13

14 Section 4 GIS Data Standards There are multiple types (and quality) of data sets created and used by the Town within the enterprise GIS. To facilitate sharing, integration, and compatibility, the Town requires all data generated for, and managed by the enterprise to adhere to basic standards as follows. All geospatial data must meet or exceed the documented standards regardless of scale. Testing against existing base data combined with statistics (about how and what data was collected), ultimately determines the accuracy of the data in question. This process will confirm relative accuracy of new or unintegrated geospatial data, and how compatible it is with the enterprise system Spatial Reference Digital data provided to or produced for the Town needs to be in the North American Datum 1983 (NAD83) horizontal geodetic datum and referenced in the North Carolina State Plane Coordinate System (NCSPC); and in the North American Vertical Datum of 1988 (NAVD 88). The NCSPC is the official survey base for the State of North Carolina. The specifics of the referencing system requirements follows: Projection: Lambert Conformal Conic Geographic Coordinate System: GCS_NAD_1983_2011 FIPS Zone: 3200 False Easting: (as per ESRI) False Northing: 0.0 (as per ESRI) Central Meridian: Scale Factor: Latitude of Origin: Linear Unit: US Foot Angular Unit: Degree Horizontal Datum: North American Datum of 2011 Vertical Datum NAVD 88 Spheroid GRS1980 Semi Major Axis: Semi Minor Axis: Inverse Flattening: The Town requires that all coordinate values be reported in units of US survey feet, with the units clearly defined in the attached metadata. This requirement applies to all ground survey data as well, which must be submitted with equivalent NCSPC values for all points, if the points were not originally captured in NCSPC. Page 14

15 4.2 - Data Creation and Collection There are many techniques that can be used to create geospatial data, which in turn can be submitted to the Town. The two most common are: A. Compiling data from base sources like digital imagery, using interactive editing, digitizing overlays which are then scanned and georeferenced, vector based analysis, classification, etc. B. Data captured from the field using measurements technology instruments like Terrestrial Positioning System (TPS), Global Positioning System (GPS), Digital Levels, and Lidar. Base Sources: Any recent digital aerial photography at large or small scale must meet or exceed the NSSDA (Standard for Spatial Data Accuracy) testing methodology. Accuracies for historical digital imagery (prior to 2002) can be reported using the NMAS (National Map Accuracy Standards). Non-digital (hard copy) base maps: Since some data needed to represent historical conditions may have to be generated from non-digital sources, those sources must meet a NMAS threshold value for the appropriate. User geo-referenced digital imagery: Geo-referencing is the process of defining a coordinate system and a projection for an undefined data source, such as a historic map or image. In those cases where the data submitted to the Town was generated from a source geo-referenced by the data provider, the source material should be identified and its accuracy characteristics described, along with a full description of the geo-referencing process used by the data provider. Control point files with a report about accuracy, errors, and procedures are also to be provided. Vector data sets: Data submitted to the Town may be based on existing vector data sets. In these cases, a full description of the accuracy of the base vector data sets (including the accuracy of the source layer) used to create the data needs to be reported. In cases where data was created from base sources not referenced to NC State Plane, all data will be projected to NC State Plane before submittal Accuracy Requirements Data submitted to the Town must be accompanied by a full description of the processing used to create said data, and of its accuracy. This description should include information on both the positional accuracy (horizontal and vertical), and the accuracy of any attribute information captured. Page 15

16 That being said, base information used to create geospatial data must at least meet the NMAS threshold accuracy standards as listed in Table 4.3. Table Supported Data Formats The Town s Enterprise system is built using ESRI software. With that in mind, there are several formats acceptable for data submitted. These formats are listed below in order of preference, with any specific requirements applicable to each: 1). Geodatabase (File or Personal): Data developed and submitted to the Town shall be in a compatible version of ESRI s file or personal geodatabase (10.45 version as of 11/1/2017, contact the Town s GIS Division for verification). All data submitted must be topologically correct. Geodatabases will adhere to the following minimum standards: All feature classes included in the geodatabase will exist in one or more feature data sets The XY coordinate system for all feature datasets and feature classes will be in NCSPC Z coordinate system will be NAVD_1988 The XY tolerance will be at least 0.01 ft. A closer tolerance may be used where the accuracy of the data, such as that collected with survey grade GPS, supports it Page 16

17 The XY resolution will be at least 0.01 feet Topologies will be created for all feature datasets and feature classes and all data will be submitted with no topologic errors For topologies that involve more than one layer, the most accurate layer will be given the highest rank The minimum topologic rules are: Features will not be duplicated Coincident boundaries will be corrected within a feature dataset (features that share boundaries with features in other feature classes in the dataset) Linear features will not overlap; i.e., all line intersections will require a node Linear features will maintain correct arc directionality for any data set with flow directions Linear features will not have pseudo-nodes unless they are required to maintain a change in arc attribution Polygons must close Polygons will have no overshoots or dangles Polygons will not overlap Polygons sharing edges will not have gaps Topologies should be submitted as part of the geodatabase delivered to the Town so that completeness and accuracy can be easily verified. In some cases, the Town s GIS may develop project specific geodatabase templates for data submittal consistency. Users should investigate with the GIS Division whether or not geodatabase templates have been created and posted for download before developing a geodatabase for a project specific data submittal. 2). Shapefiles: All shapefile data sets must include at a minimum the following files:.shp (the file that stores the geometry).shx (the file that stores the feature geometry index).dbf (the file that stores the feature attribute information).prj (the file that stores the coordinate information) When applicable, the following files should also be submitted:.sbx and.sbn (the files that store the spatial index of the features).ain and.aih (the files that store the attribute index of active fields in the attribute table) Shapefiles must be created so that the following basic topologic rules are not violated: Features will not be duplicated Page 17

18 Linear features will not overlap; i.e., all line intersections will require a node Linear features will maintain correct arc directionality for any data set with flow directions Linear features will not have pseudo-nodes unless they are required to maintain a change in arc attribution Polygons must close Polygons will have no overshoots or dangles Polygons will not overlap or self-intersect Polygons sharing edges will not have gaps Polygons will have one and only one label point 3). Raster Data Raster data sets that encompass imagery or elevation data are less likely to be submitted to the Town than vector data (points, lines, polygons). However, in those cases where submissions of raster are required, the following data formats will be accepted. ArcInfo grids (integer or floating point) Triangular Irregular Networks (TINs) MrSid (version 2, 3 or 4) with world file Tiff, Geotiff, with world file Jpeg, jpeg2000 with world file ERDAS Imagine ASCII All raster data sets must contain projection information, and projections will be defined with the following parameters: Projection North Carolina State Plane Units Feet Datum NAD83 Additionally, all raster data submitted to the Town must meet minimum positional accuracy standards as described in Section ). Computer Aided Drafting (CAD) While there are many different CAD file formats, there are three major formats which will be accepted by the Town: AutoCAD DWG (AutoCAD 2009, Software Version 17.2, Format Version 2007 and higher) AutoCAD DXF (AutoCAD 2009, Software Version 17.2, Format Version 2007 and higher) Microstation DGN (version 7.x and higher) Page 18

19 All CAD data submitted will comply with the following minimum specifications: For all formats, the CAD files reference is NCSPC US Feet, NAD83. Unreferenced files will not be accepted. All data will be exported using a 16 decimal places option, so that double precision accuracy will be maintained. In addition, a text file listing individual layer names and descriptions shall be submitted with each CAD data set. All CAD files regardless of software version used to create the files will follow the structure outlined in the draft CAD template available from the GIS Division Annotation for each layer shall be placed in separate annotation layers At least two separate digital files are required for each submission: One file will be a digital file in format containing the full survey drawing. This drawing must be created at its real North Carolina State Plane Coordinates, NAD83, NORTH position and the view shall be un-rotated from the coordinate system so that the NCSPC NORTH points are vertical in the screen One file will contain all objects on the correct layer. Meaning, multiple features will be included on the same layer (ie all manhole points on manhole layer, all property lines on property line layer). Specific requirements may be requested on a project by project basis. F). Other Data formats Other data formats may be accepted by the Town based on project requirements. It is strongly suggested that those submitting data first check with the Town s GIS Division to verify acceptable formats GIS Data Matrix Once completed, existing geospatial data created, edited, or updated will utilize the GIS Data Matrix document for rules/relationships within the enterprise system (see section 4 for details). For new features created or submittals, the following dataset and attribute naming conventions are applicable: Dataset naming conventions Dataset names will contain only alphanumeric characters (i.e. letters, numbers) Dataset names will start with a letter Dataset names will be entirely in lowercase No spaces, dashes, special characters other than an underscore will be used Dataset names will be 10 characters or less Common abbreviations should be used where applicable Page 19

20 Attribute Field Naming Attribute field names will contain only alphanumeric characters (letters and numbers) and underscores Attribute field must start with a letter No spaces, dashes or special characters other than an underscore will be used Attribute field names will be 10 characters or less to avoid data conversion issues with truncation Metadata for GIS and GPS Data GIS and GPS data must conform to the Esri Item Description (include details/description) model at a minimum. This includes the following: 1. Thumbnail snapshot of data 2. Summary explaining general purpose of data 3. Description which provides a detailed explanation of the purpose, data collection methods, expected maintenance schedule if any, expected accuracy and other pertinent information. 4. Credits indicating what organization, department and persons created and/or maintain the data 5. Use limitations or disclaimers 6. Spatial extent Federal Geographic Data Committee (FGDC) and International Organization for Standardization (ISO) standards are also accepted as long as they also contain the required information listed at a minimum. Additionally, avoid using fields in the database to store metadata about the feature class, e.g. a Date Loaded field. Such information is required in the metadata and therefore superfluous in the attribute table. The only exceptions are to either capture row specific metadata (e.g. Modified By), where each record may have different values, or where the original source of the individual features may vary and need to be tracked. In the second case, the metadata should also document the fact that there are multiple data origins. Section 5 Data Compilation Goals When consolidating and managing large data sets created, edited, and published by multiple users and departments, it becomes necessary to form a process for compilation in order to reduce duplication of effort and improve data accuracy/integrity. This process is extremely important in establishing and maintaining the organizational structure of an enterprise geodatabase, without which data is virtually impossible to find, analyze, or update in a multi-user environment. The creation of a GIS Data Matrix is one of the Page 20

21 recommendations from the companion GIS Roadmap document; developed in conjunction with this GIS Data Standards. The GIS Data Matrix will be created by the Town s GIS Division, along with any individuals or organizations that will utilize data in the future. Surveys will be sent to said individuals and department, for the purpose of creating a master list detailing GIS/CAD data currently maintained by them, along with detailed information such as Data Format, Editor, Date Created, etc. Below is an example of how the Data Matrix may look: This document will be critical in the creation and maintenance of a true enterprise GIS by the Town, and is an important part of the recommendations found within the GIS Road Map document. At this time, the Town utilizes a decentralized file based system for storing and managing its GIS data. Moving to an enterprise solution and adopting a Data Owner methodology, will dramatically improve the effectiveness, accuracy, and efficiency of the Town s use of GIS. What this means is that while data is captured and updated at a department level (Data Owner), it actually resides in a centralized location maintained by the Town s GIS Division and available to be viewed or utilized with all parties who could benefit from the information. A practical example for the Town would be that the Planning department would maintain the official Zoning layer using GIS desktop software, but the actual data would be in a centralized location. 1) In order to implement this process the Town will adopt another recommendation from the GIS Roadmap, which will be the creation of a group formed of department heads GIS, Planning/Zoning, Engineering, Stormwater, etc.), SME s (subject matter experts), and Data Editors in order to form the GIS Working Group : Page 21

22 These individuals will become the authority who determines Data Owner responsibilities, resolve duplicate data or workflows, and manage conflicts that inevitably arise when implementing change of this scale Determine project priorities, timelines, and discuss shared budgetary plans to maximize the returns gained from shared resources (funding, personnel, responsibilities, etc.). 2) The GIS Working Group should perform a thorough review of the GIS Data Matrix. This will also allow contributing departments and Data Editors to make determinations about: Who will have responsibility for specific data layers (Management), capture/collection (Author/Creator), and who shall be the Editor Identify the most up to date version of data, and reconcile duplicate efforts Establish a timeline for project completion and updating of the enterprise 3) After completing the review of the GIS Data Matrix, the GIS Working Group will then utilize the Town s Data Model (identified as part of GIS Roadmap), for the enterprise design and import existing data into the appropriate feature datasets/tables. Additionally, it will be necessary to: Assign appropriate user roles of Management, Author/Creator, Editor, and Administration (as defined within this document) to individuals within the organization. As new data/projects are created, the Data Owner (Department, Editor, and SME) will work with the GIS Working Group to ensure adherence to the enterprise data model and update the GIS Data Matrix accordingly Page 22

23 Information sources consulted and used: APSRS Guidelines, Vertical Accuracy reporting for LiDAR Data, Version 1.0, ting_for_lidar_data.pdf NC Board of Examiners for Engineers and Surveyors, Geospatial Positioning Accuracy Standards Part 3: National Standards for Spatial Data Accuracy, Digital Ortho-imagery standards: Content Standards for Digital Orthoimagery, Federal Geographic Data Committee, February, 1999, Geospatial Positioning Accuracy Standards Part 3: National Standards for Spatial Data Accuracy, AutoDesk (2011). AutoDesk DXF Reference. Retrieved on August 3, 2011, ESRI OGD. ESRI Support, Online GIS Dictionary. Retrieved June 24, 2011, FGDC, (1998), Geospatial Positioning Accuracy Standards, Part 3: National Standard for Spatial Data Accuracy, FGDC-STD Washington, D.C., Federal Geographic Data Committee Kansas Association of Mappers, The Kansas professional society for mapping and GIS, GIS Glossary, Retrieved June 24, 2011, Minnesota Land Management Information Center (LMIC), Positional Accuracy Handbook: Using the National Standard for Spatial Data Accuracy to measure and report geographic data quality, Page 23

24 National Institute of Standards and Technology (NIST) for Federal computer systems, NCGIA. A Glossary of GIS Terminology (1992), National Center for Geographic Information and Analysis (NCGIA), publication 92-13, New York State GPS Glossary, New York State Archives, Geographic Information Systems Development Guides (1996), NGA FAQs. National Geodetic Survey, FAQs, New Jersey Department of Environmental Protection GIS Data Standards, NGA National Geodetic Survey, National Ocean Service, National Oceanic and Atmospheric Administration, Rockville, MD, Geodetic Glossary, OSGEO GeoTiff. Open Source Geospatial Foundation, Univ. of Texas Library, Perry-Castañeda Library, Map Collection, Glossary of Cartographic Terms, URISA Quick Study, GIS Glossary of Terms (Parr, Daniel M., 2000), URISA Surveying and Land Records, Glossary of Terms (von Meyer, Nancy, 2002), pdf US Census Bureau, State and County Quick Facts, Federal Information Processing Standard (FIPS), Page 24

25 USGS, Digital Orthophoto Quadrangles Fact Sheet (May 2001), USGS, Frequently Asked Questions on FGDC Metadata, USGS NMAS. United States National Map Accuracy Standards, USGS, Transverse Mercator Projections and U.S. Geological Survey Digital Products, Page 25