GIS User Guide for the County of Calaveras Written by Dave Pastizzo GIS Coordinator Calaveras County San Andreas, California August 2000
Table of Contents Introduction..1 The Vision.1 Roles and Responsibilities...1 Committees..3 Work Groups....3 Appendix A: GIS Data Standards Defined.......4 Appendix B: GIS Spatial Data Standard.....5 Appendix C: GIS Data Catalog........10 Appendix D: Sample MetaData Form..11 Appendix E: Sample ArcView Project Directory Structure..13 Appendix F: GIS Related Links...14 ii
Introduction: This document is an attempt to set up an organizational structure for utilizing our new GIS technology in a way that benefits us all. The system outlined below is intended to provide the structure (quite ridged at times) to insure that our computerized files and storage will be useful to everyone over the years. Within this organizational structure there are folders and files, which are shared by everyone, that require a well thought out and ridged set of rules for use, as well as folders and files used for individuals only that have no pre-determined structure, other than space limitations. While it may seem confusing and cumbersome at first, the rhyme to the reason should become apparent as you begin using the GIS resources for your work. The Vision: The GIS will become the backbone of all the IT systems in the County. Virtually all of the information gathered and used by the county can benefit by being linked to spatial data. The GIS will further be used to distribute the county datasets to the general public within the constructs of the Memorandum of Understanding (MOU). Roles and Responsibilities: - GIS Coordinator (Dave): Is responsible for the publishing of GIS Department map products as well as for developing and maintaining the Common data stored on the CCGGIS server. The GIS Coordinator will insure that all data on the CCGGIS Server is backed up daily. The GIS Coordinator will facilitate the development of a County wide GIS infrastructure by forming committees and workgroups as outlined in the MOU and according to internal county needs. Will oversee and administer the saving of competed projects to a tape archive in such a way that they can easily be accessed at a future date. - GIS Development Team (Pam, Hans, & Dave): Are responsible for delivering InTERnet and InTRAnet applications tailored to meet specific county IT needs. These applications will be focused on improving work flows through the integrated use of spatial and tabular data. - Users (Everyone): Are responsible for contributing to the development of the County GIS infrastructure. For following the structures and procedures for using the Calaveras County GIS computer resources. - Network Administrator Group: Are responsible for developing and maintaining the county computer resources which the GIS depends on. - GIS Data Stewards: In a multiparticipant GIS, it is important to establish formal responsibilities for the creation and maintenance of GIS datasets that will be broadly distributed and used. It is expected that within two years the countywide GIS will have over 100 spatial datasets from a variety of sources. To avoid redundant efforts, a Data Steward should be identified for each dataset that is locally maintained. For example, the Data Steward for the parcel layer would be the mapping expert(s) in the Assessor s office. Initially, the Data Steward for many of the layers will be the GIS Coordinator, but as GIS expertise and capabilities increase, more of the data stewardship responsibilities will be with the department experts most familiar with the datasets. In addition to care taking specific GIS datasets, the Data Steward will also have the responsibility for creating and maintaining metadata. Figure 1 below shows the flow of GIS information between the department GIS Data Stewards and the GIS Coordinator. The GIS Data Steward creates and maintains both the GIS data and metadata. At regular intervals, the GIS Data Steward sends the GIS data and metadata to the GIS Coordinator. The GIS Coordinator checks the data per established standards and posts the data into the centralized Spatial Data Warehouse for further distribution. The GIS Coordinator also updates the central Spatial Data Catalog. 1
Spatial Data Coordination GIS Coordinator Spatial Data Catalog Layer Description Steward Date Metadata Layers Data Steward Roads Data Steward Parcels Data Steward! Create & maintain spatial data! Create & maintain metadata! Participate on GIS Committee & Technical GIS Workgroups GIS Coordinator! Obtain layer updates from Data Stewards! Check data per standards for quality, accurancy, and completeness! Load data into Spatial Data Warehouse! Apply appropriate security! Update Spatial Data Catalog! Participate on Policy Committee, GIS Committee and Technical GIS Workgroups Spatial Data Warehouse Geodetic Control Public Land Survery Parcels Governmental RDBMS Units Join Orthophotography Transportation Hydrography... 7/19/00 - VESTRA Resources, Inc. sdc6.vsd Figure 1. Spatial Data Coordination. (with permission of Vestra Resources Inc.) 2
- Committees: - GIS Policy Committee: This committee is made up of members of the organizations participating in the Memorandum of Understanding (MOU). The primary function is to establish policies for governing the county GIS, as well as to facilitate joint projects between the MOU participants. - GIS Technical Committee (i.e. GIS Committee): This committee is made up of County wide users of GIS. The primary function is to work out the day to day nitty-gritty details of how the county GIS will function and meet the diverse needs of the county. It is also a place where knowledge can be shared, and questions answered by sharing the breadth of experiences of the committee members. Implementing a county wide GIS is a major undertaking, and to help to insure that it will meet all of the diverse needs of the county, we will need the experience and thinking power of representatives of all the current and future users. - Work Groups: Work groups are tasked with developing specific solutions to particular GIS related issues. - Standards Work Group: Develop County wide standards for Spatial Data Storage, Metadata, and Spatial Accuracy and Resolution. - APN# and Addressing Work Group: Develop the APN and Addressing standards for linking tabular data (i.e. Megabyte, Sierra Permits, etc.) to the Framework Spatial Data Sets (parcels and roads). - Geodetic Work Group: Develop standards for improving and updating our Public Land Survery (PLS) layer. The majority of Calaveras County has poor geodetic control. - Cadastral Work Group: Develop standards for maintaining and updating the parcels layer, as well as TRA, and other Cadastral datasets. - Transportation Work Group: Develop standards for maintaining and updating the road center line layer, as well as other transportation datasets. - Environmental Work Group: Develop standards for maintaining and updating the environmental layers (i.e. wells, hazardous waste, etc.). 3
Appendix A: GIS Data Standards Defined Coordinate System Standard a Coordinate System, for the purposes of GIS, is a system that facilitates referencing features on the earth s spherical (3-D) surface onto a flat (2-D) map, or computer screen. Over the last couple hundred years, many Projections of the earth s 3-D surface onto 2-D maps have been devised. Each projection type introduces its own form of distortion into the data, while preserving other aspects of the features projected. Some projections distort distances while preserving shape, some distort shapes while preserving lengths, etc. So, each projection has its advantages and disadvantages, and some are better at different scales than others. The Coordinate System Standard for Calaveras County is the State Plane Coordinate System (CA Zone III), North American Datum of 1983 in feet. The State Plane Coordinate system is the standard system used by all counties in the US. GIS Data Scale Standard The scale of GIS data has a direct relationship on data resolution and accuracy. At a 1:24,000 scale (such as USGS Topo Maps) a line representing a road on the map is 100 wide, so inaccuracies of 50 are not noticed. But a on a 1:100 scale assessors bookpage, a 20 inaccuracy is easily noticed. So, the scale that the county chooses as its base scale is an important standard to determine. GIS Metadata Standard GIS metadata is information about the GIS dataset. Each GIS dataset to be available in the countywide Spatial Data Warehouse should be fully documented. It is important that the County adopt a GIS metadata standard. At a minimum, each data layer should have the following information: Dataset name Brief description Dataset accuracy Source information Geographic feature type Data dictionary of codes used Date of last update Contact information Tabular Data Key Fields Standard The link between spatial and tabular datasets is important for GIS application development. The format of the assessor s parcel number (APN) and street address (situs), as well as the street address of Public Works Road layer, are typically the most important fields to standardize. The APN field format should follow the same format as the Assessor s property information system (Megabyte System). The situs should be formatted to facilitate GIS address matching or geocoding. Digital Submission Standards To facilitate data exchange and incorporation of cooperator data into the GIS Data Warehouse, digital standards and procedures need to be established. Basically this is the procedure to be followed when a GIS data layer is submitted to the GIS Coordinator for addition to the GIS Data Warehouse, thus making it available to all users. This standard is also important for sharing of GIS Data between MOU participants and other organizations. This would include things like how often a data layer is updated, and inclusion of Metadata for each submitted layer. 4
Appendix B: Spatial Data Standard (A Hierarchical Directory Structure): Sample Calaveras County Spatial Data Standard Diagrams: The following diagrams are a proposed representation of the Calaveras County Directory Structure on the counties CCGGIS Server. Figure 2 is an overview of the top directories on the server. The next 4 diagrams (Figures 3 6) are detailed views of each of the four main directories. These diagrams are based on the Tri-Service Spatial Data Standard, which were designed to complement the Federal Geographic Data Committee (FGDC) data standards. An example and description of the Tri-Services data standard can be viewed at the GIS section of the Bakersfield web site. Figure 2. Overview of the CCGGIS Server Directory Structure. 5
Figure 3. Detailed View of the Spatial Data Directory Structure. 6
Figure 4. Detailed View of the Image Data Directory Structure. 7
Figure 5. Detailed View of the GIS Users Directory Structure. 8
Figure 6. Detailed View of the Utilities Directory Structure. 9
Appendix C: GIS Data Catalog The GIS Data Catalog is a tabular listing of the GIS data stored on the CCGGIS Server. It has been set up to follow the Tri-Service Spatial Data Standard diagramed in Appendix B of the GIS Users Guide. The Spatial Data Standards were designed to complement Federal Geographic Data Committee (FGDC) data standards. The basic structure of the data standard is a hierarchical directory structure which goes from a broad data Entity Type (i.e. Transportation) to a sub Entity Class (i.e. Vehicle), to a even more specific actual Entity (Road Centerlines). The idea, is that by following this entity hierarchy, you can find the GIS layer you are interested. The Actual GIS data layer (shapefile, coverage, etc.) reflects this structure in its name as follows: TTCCCEEE.xxx Where TT are a two character abbreviation for the Entity Type (Transportation), CCC is a three character abbreviation for the Entity Class (Vehicle), EEE is a three character abbreviation for the Entity (Road CenterLine), and xxx is the standard three character file extension (shp). A sample of the GIS Data Catalog is located on the Calaveras County web page next to the link to this Users Guide. 10
Appendix D: Sample MetaData Form Calaveras County GIS MetaData Form Layer Name: Entity Set: Entity Class: Entity Type: Creation Date: Layer Format: ShapeFile Coverage Grid Tin Image Geographic Feature Type: Point Line Polygon N/A Contact Name: Contact Phone: Contact Department: Contact Email: Keywords: Description: Abstract: Purpose: Source: Update Log: Date: Edit/Change: Attributes: Attribute Accuracy Statement: 11
Projection Information: Projection: Lambert Conformal Conic First Standard Parallel: 37.066667 Second Standard Parallel: 38.433333 Longitude of Central Meridian:-120.500000 Latitude of Projection Origin: 36.500000 False Easting: 6561666.666667 False Northing: 1640416.666667 Coordinate System: State Plane Units: Feet Datum: NAD83 Fipszone: CA III Zone: 0403 DATA ACCURACY: I. Disclaimer of Liability and Warranties: A. You understand and agree that it is possible that errors and omissions will occur in data input or programming done by The County of Calaveras to provide that data. You further understand and agree that it is probable that errors and omissions will occur in the record keeping process, especially when a large number of records are developed and maintained, and that such data may not meet your standards as to accuracy or completeness. Notwithstanding, you agree to take the data "as is", fully expecting that there may be errors and omissions associated with the data. B. You further understand and agree that The County of Calaveras makes absolutely no warranty whatsoever, whether expressed or implied, as to the accuracy, thoroughness, value, quality, validity, suitability, condition or fitness for a particular purpose of the data or any programming used to obtain the data, nor as to whether the data is error-free, up-to-date, complete or based upon accurate or meaningful facts. C. You further understand and agree that you forever waive any and all rights, claims, causes of action or other recourse against The County of Calaveras for injuries or damages of any type, whether direct, indirect, incidental, consequential or otherwise, resulting from any error or omission in the data or in any programming used to obtain the data, or in any manner arising out of or related to the data retrieved herein. You agree that The County of Calaveras shall not be liable to you for any liability, claim, loss, damage, injury or expense of any kind caused or alleged to be caused, directly or indirectly, by the inadequacy of data obtained from The County of Calaveras, by any deficiency of The County of Calaveras or your systems, by any delay or failure to provide service, or by any other interruption, disruption or loss to your operations. II. Indemnification: You agree not to provide a copy or partial copy of any data to any other party, including consultants under contract with you, without disclosing that the copy or partial copy was obtained from The County of Calaveras and without attaching a duplicate of these Terms and Conditions. 12
Appendix E: Sample ArcView Project Directory Structure: The following directory structure is offered to ArcView users as a help to get started. This is the basic structure I have developed for keeping myself straight on a project. Once you have started two or three projects that are ongoing, you will quickly experience a need to be organized, to keep all those shapefiles in order. This directory structure will be available on the CCGGIS Server under a Utilities Directory. It is offered as a start, feel free to modify it to meet your unique needs. -?Descriptive Name?: A name describing the project. - Projects: For ArcView Project files (.apr). - Exports: For files exported from ArcView, such as JPEG and TIF images of Layouts. - Imports: For files you import into ArcView such as ArcInfo export files (.e00). - Data: For all data associated with this project. - Tables: Used for storing Tabular Data such as Excel files and other spreadsheet type data related to this WaterShed - Images: Used for storing GIS/Map related Images such as Orthophotos or Scanned Topos. - GPS: Used for storing GPS files for the Project. These files are generated in the GPS application (Trimble s PathFinder Office). -?DiscriptiveName?: A name describing the features captured by GPS and a date (MMDDYY). - BaseStation: For saving downloaded Base Station files. - Corrected: For storing differentially corrected Rover files. - Rover: For storing raw Rover file. - ExportShpFiles: - Spatial: - ShpDD: Shapefiles in Decimal Degrees. - ShpSPF83CA3: Shapefiles projected in State Plain Feet, NAD 83, California Zone 3. - ShpUTM27Z10: Shapefiles projected in UTM, NAD 27, Zone 10. - GPSShpFiles: For storing Shapefiles exported from GPS inputs. - ShpDD: GPS Shapefiles in Decimal Degrees. - ShpSPF83CA3: GPS Shapefiles projected in State Plain Feet, NAD 83, California Zone 3. - ShpUTM27Z10: GPS Shapefiles projected in UTM, NAD 27, Zone 10. - MetaData: Documents which describe the layers (either.doc or.html). 13
Appendix F: GIS Related Links For a list of GIS related web site links, refer to the Links to Additional GIS Information on the main page of the GIS Project section of the Calaveras County web site. 14