IMPERIAL COUNTY PLANNING AND DEVELOPMENT GEODATABASE USER MANUAL FOR COUNTY BUSINESS DEVELOPMENT GIS June 2010 Prepared for: Prepared by: County of Imperial Planning and Development 801 Main Street El Centro, CA 2243 Nolte Associates, Inc. 1605 West Main Street El Centro, CA 92243 Funded by: Community Development Block Grant
TABLE OF CONTENTS SECTION PAGE 1.0 INTRODUCTION 2 2.0 DATASETS 2 3.0 SYMBOLOGY 6 4.0 MAINTENANCE 7 5.0 MODEL BUILDER 9 1
1.0 INTRODUCTION Nolte Associates, Inc. has been retained by Imperial Planning and Development Services to develop a plan for a geographic information system (GIS) that will facilitate economic development within the County. The project was funded by the Community Development Block Grant program. The spatial data for the County Business Development GIS Project is organized in an ESRI File Geodatabase. An ESRI file geodatabase is a collection of organized GIS datasets held in a file system folder. The file geodatabases are ideal for storing and managing spatial data. Each dataset in the file geodatabase can store up to 1 Terabyte of data. The database structure is optimized for fast performance. A key geodatabase concept is the dataset. It is the primary mechanism used to organize and use geographic information in ArcGIS. The geodatabase contains three primary dataset types: Feature classes Raster datasets Tables Creating a collection of these dataset types is the first step in designing and building a geodatabase. Users typically start by building a number of these fundamental dataset types. Then they add to or extend their geodatabase with more advanced capabilities (such as by adding topologies, networks, or subtypes) to model GIS behavior, maintain data integrity, and work with an important set of spatial relationships. 2.0 DATASETS The structure for the County Business Development geodatabase is grouped into datasets of related information. The figure below shows groups for Administration, Basemap, Cadastral, Environment, Facilities, Infrastructure, Land Use, and Transportation. This structure is derived from the proposed data sharing model called Data for the Nation. Other components were taken from ESRI s Local Government Data Model. The horizontal coordinate system is California State Plane, Zone 6 (feet). 2
Administration Dataset This dataset includes administrative and legal boundaries for governmental units. Municipal, county, school district and water district boundaries are included. Below is a list of layer names and data types. These layers should be updated whenever there is a change in boundaries. Imperial County Polygon Municipalities Polygon Imperial_Irrigation_District Polygon Elementary_School_Districts Polygon Secondary_School_Districts Polygon Unified_School_Districts Polygon Cadastral The cadastral dataset includes details on the ownership of land. The parcel layer shows the dimensions of the parcels, ownership information, and assessed value. The parcel layer is anchored to a survey control network to provide an accurate geospatial framework. It is recommended that a new parcel layer be loaded into the geodatabase at least on a quarterly basis. Parcels Polygon 3
Census This dataset includes the spatial and tabular data from the 2000 US Census. There are three layers of information in this dataset: Census Tracts, Block Groups, and Blocks. Tracts are statistical subdivisions of the County that generally have stable boundaries with an average of about 4,000 people. Tracts are divided into Block Groups. Block Groups are further divided into Blocks, the smallest geographic unit for which the Census tabulates data. Data from the 2010 Census should be available in the second half of 2011. Census Tracts Census Blocks Census Block Groups Polygon Polygon Polygon Elevation This dataset contains surface elevation information. The primary dataset is the 10 meter National Elevation Dataset. Elevation points, contour lines, TINS, DEMS, and hillshades could also be stored here. A TIN is a triangular irregular network of elevation points. A DEM is a digital elevation model arranged in a regular grid. Elevation Raster Environment This dataset includes physical features and landform characteristics such as geology, soils, and vegetation. Environmental hazard dataset such as flood and earthquake zones are also included. There are nine fault zones within Imperial County. The most significant fault is the San Andreas, which extends from Mexico into northern California, and the maximum earthquake intensity predicted for the fault is a magnitude 8.3. Although the County is located in the desert with very low precipitation, it is sometimes subject to heavy rains and subsequent flooding. Floodplain management is the key to effective flood control within Imperial County. The Federal Insurance Administration delineates areas of special flood hazards and floodways through the official digital Flood Insurance Rate Map (DFIRM). Critical_Habitat_USFWS Polygon Earthquakes EQ_Faults Line EQ_Hazards Polygon Flood_Hazard_Zone Polygon Groundwater_Basins Polygon Hydrology Line National_Wetland_Inventory Polygon Precipitation_Annual Polygon Sensitive_Lands Polygon 4
Imagery Imagery can provide important reference or base map information. The primary dataset is color orthophoto imagery of 0.5 and 1 foot resolutions from a 2008 SCAG project. Other imagery is available including the 2009 NAIP 1 meter orthophotos. Imagery_SCAG2008 ortho2009 Infrastructure and Facilities This dataset includes point locations of critical facilities such as fire stations and hospitals as well as line and polygon representations of infrastructure such as canals. The source of the facilities information is the FEMA HAZUS Dataset of August 2009. CanalGate Canals Communication FireStation HealthCare PoliceStation Power School WasteWater Line Land Use and Land Cover This dataset defines the primary ways that the land is used. Land use, zoning, planning, and economic incentive zones are included. Also included are Important Farmland areas determined by soil type. The enterprise zones, land use, and zoning index were adapted from Imperial County CAD files and PDF maps. It is understood that the land use is currently in the process of being converted to GIS as part of another project. When this project is complete, the draft land use in this geodatabase can be replaced with the new land use layer. The Zoning Index was created with a link field that allows the user to click on a zone to open a display of the appropriate PDF zone map. Calexico_Enterprise_Zone Polygon General_Plan_Land_Use_DRAFT Polygon Important_Farmland2006 Polygon IVEZ_Boundary Polygon Targeted_Employment_Area Polygon Zoning_Index Polygon 5
Transportation The transportation layer contains information about highway, street, and railway network. This dataset will be useful to determine the proximity of a site to major though fares. Historic traffic volumes would help augment this layer. Airport Centerline Railway Highways Line Line Line 3.0 SYMBOLOGY Creating a collection of these dataset types is the first step in designing and building a geodatabase. Users typically start by building a number of these fundamental dataset types. Then they add to or extend their geodatabase with more advanced capabilities (such as by adding topologies, networks, or subtypes) to model GIS behavior, maintain data integrity, and work with an important set of spatial relationships. Symbology layers were created for each layer in the geodatabase. The layers were set up to provide a user friendly display by customizing the scale the layer is drawn at, the transparency, the symbol, and the color. To apply a symbology to a layer follow these steps: 1. Right-click the layer for which you want to import symbology in the ArcMap table of contents. 2. Click Properties. 3. Click the Symbology tab. 4. Click the Import button. 5. Click the option to import from a layer file. To import from a layer file, click the Browse button and navigate to the file from which you want to import. 6. Click OK. 6
4.0 MAINTENANCE Broken Links The link between the MXD project and the supporting geodatabase may be broken if the geodatabase is moved. To repair a broken data link, follow these steps: 1. Locate the layer with the broken link in the table of contents. It will have a red exclamation mark next to it, and its check box will be unavailable. 2. Right-click the layer, point to Data, and click Repair Data Source. 3. Navigate to the data source you want and click Add. ArcMap repairs the layer using the data source you specified and also automatically repairs other broken layers if it can find their data sources in the location of the data source you specified. Added and deleting data layers To import a datalayer into the geodatabase, simply right click on the dataset you want to import into and Select Import -> Feature Class. Layers can be deleted by right clicking on the layer to delete and choosing delete. 7
Backup It is important to maintain a schedule of frequent backups of the database. If the database because corrupted it is relatively use to go back to a recent version. It may also be necessary to obtain an earlier version to find historical information. The geodatabase can be compressed before backup to reduce storage space. To compress a dataset in the geodatabase, right click on it and choose Compress File Geodatabase Data. 8
5.0 MODEL BUILDER ModelBuilder is an application in which you create, edit, and manage models. Models can be a great way to query the geodatabase to find the answer to a specific question. In the example below a new empty model was first set up by doing the following: 1. Right clicking in the ToolBox area and selecting New Toolbox. 2. Name the Toolbox 3. Right click on the toolbox and Select New Model 4. Open the new model window. Then existing tools can be added by drag and drop into the model window. The tool is then linked to existing datasets in the geodatabase by clicking on the desired yellow box function and selecting the input data. In the example below, the existing tool Layers and Table Views -> Select Layer By Location was used to find parcels within 1000 feet from schools. Then the Layers and Table Views -> Select Layer By Attribute was used to narrow down the parcels to ones that are larger than one acre. 9