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ОглавлениеChapter 2
Data Storage
This section of the exam tests your understanding of data storage. With ArcGIS, you can store your data in a way that fits your system architecture and existing business workflows. This functionality includes storing data as individual files, in relational databases, in geodatabases, or in the cloud. This chapter covers ways that ArcGIS handles data, including the capabilities of the geodatabase and its supported data elements. This chapter is divided into five skills.
Skills measured
1 Given requirements for a specific project, determine how to design a geodatabase.
2 Select appropriate data formats for an intended use.
3 Given a task, determine the data, settings, and parameters for creating a complex dataset.
4 Given a task, determine the data, settings, and parameters for creating an address locator.
5 Given a scenario, determine how to synchronize replicated data.
Given requirements for a specific project, determine how to design a geodatabase
A geodatabase gives you the ability to store data in a central location for easy access and management. It can be used in desktop, enterprise, or mobile environments, and it supports the storage of many types of GIS data. A geodatabase allows you to manage your data using advanced capabilities for modeling behavior, maintaining data integrity, and working with spatial relationships. This section covers the fundamentals of geodatabases and some of their supported data elements. This skill has three parts: (1) geodatabase fundamentals, (2) associating features and records, and (3) topology.
Geodatabase fundamentals
A geodatabase provides structure and a framework that allows you to accurately model the real world while maintaining the relational integrity between your spatial data. Three geodatabase types are supported in ArcGIS: personal geodatabases, file geodatabases, and enterprise geodatabases.
Reminder
Personal geodatabases are not supported in ArcGIS Pro.
File and personal geodatabases are supported at all license levels. These two geodatabase types also support the full information model of the geodatabase. They are designed to be edited by a single user and do not support geodatabase versioning. Enterprise geodatabases can be edited and used simultaneously by many users. They provide support for several common database management systems (DBMSs), including Oracle®, PostgreSQL, and Microsoft® SQL Server. Refer to the Help documentation for detailed tables comparing the number of users, supported storage formats, and key workflows of each of the supported geodatabase types.
When you have decided which type of geodatabase to use, you can create it using one of these methods:
1 Design a new, empty geodatabase.
2 Copy and modify an existing geodatabase schema.
3 Import the schema from other data sources.
When the geodatabase has been created, you can begin using it to organize your feature classes, raster datasets, tables, and more. You can add data to a geodatabase by creating and adding new datasets directly to it, copying and pasting datasets using the Catalog pane or the Catalog window, or using geoprocessing tools to import data from existing locations or convert data from other data formats. This table lists elements that you can create and manage in a geodatabase.
Elements managed in a geodatabase
After you add data to a geodatabase, you can extend its capabilities using rules that manage attribute values and provide additional support in multiuser editing environments. This table lists capabilities for extending feature classes and tables.
Methods for extending feature classes and tables
Geodatabases can store more than feature classes, raster datasets, and tables; they also support advanced data elements such as feature datasets, topology, geometric networks, address locators, and mosaic datasets. Feature datasets are especially important because they form the foundation of topologies, network datasets, geometric networks, terrains, and parcel fabrics. A feature dataset organizes thematically or spatially related feature classes into a collection of features that have a common coordinate system. For example, if you had a series of point, line, and polygon feature classes representing hydrologic features, you could combine them into a “hydrologic features” feature dataset. After the feature dataset was created, you could include all the participating features in a network or a geodatabase topology.
Prepare
These topics in the documentation provide details about geodatabase fundamentals.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Geodatabases > The geodatabase >Fundamentals of the geodatabaseTypes of geodatabasesFeature class basicsTable basics
Help > Data > Geodatabases > Create a geodatabase (and all subtopics)
Help > Data > Geodatabases > Add datasets to a geodatabase >Create datasets in a geodatabaseCopy feature datasets, feature classes, and tables to a geodatabaseImport data
Help > Data > Geodatabases > Data design (and all subtopics)
Help > Data > Geodatabases > Versioned data > Overview of versioning
Help > Data > Data types > Feature datasets > Feature datasets in ArcGIS Pro
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Geodatabases > An overview of the geodatabase >A quick tour of the geodatabaseTypes of geodatabasesFeature class basicsTable basics
Manage data > Data types > Tables > Designing a table > ArcGIS field data types
Manage data > Data types > Subtypes (and all subtopics)
Manage data > Geodatabases > Working with versioned data > An overview of versioning
Manage data > Data types > Feature datasets > An overview of working with feature datasets
Associating features and records
In some cases, you may want to associate features or records in one dataset with features or records in another. With ArcGIS, you can make associations using table joins and relates, relationship classes, and spatial joins. Table joins, relates, and relationship classes use a common field, known as a key, to associate records in one table with records in another table. ArcGIS supports one-to-one, one-to-many, many-to-one, and many-to-many relationships, making it easy to associate tables regardless of the nature of your data. If your data lacks a common key field, you can use a spatial join to create a relationship that is based on the location of features in your input layers.
Joins and relates are most useful when you need to create temporary associations. With a table join, the attributes from one table are virtually appended to the attributes of another table. After the join is established, you can use the information from the appended table for symbology, field calculation, and more. For example, you could associate a table of soil sample values to a land parcels layer based on a shared parcel ID field. After this association is made, you can symbolize the land parcels layer based on the soil sample values in the soil samples table. Joined tables can be exported to preserve the join in a new feature class or nonspatial table, or they can be removed if they are no longer needed. Relates allow you to identify a record in one table and see all the related records from a related table. Unlike a table join, a relate defines a relationship, but it does not append the attributes of one table to the other. Rather, it allows you to access related information by selecting features or records in your layer or table using the Explore tool in ArcGIS Pro or the Identify tool in ArcMap.
If you want to create a more permanent association, you can use a relationship class. Relationship classes are stored in a geodatabase, making them accessible to anyone using the geodatabase. They can be used to enforce referential integrity between related objects (so that when one object is modified, the related object is updated automatically), and they support all cardinalities. ArcGIS supports both simple and composite relationship classes. In a simple relationship class, the related objects are loosely coupled. For example, when you delete a record in the origin table, the key field in the destination record is nulled. You should use simple relationship classes when you have related objects that are completely independent of one another. Conversely, you should use a composite relationship class when working with related objects that cannot exist independently. In a composite relationship class, when one object is deleted, the second object (a related object) is also deleted. This approach can save you time that might otherwise be spent performing attribute edits.
Prepare
These topics in the documentation provide details about associating features and records.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Data types > Tables > Joins and relates (and all subtopics)
Help > Data > Data types > Relationship classes (and all subtopics)
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Data types > Relationships and related objects (and all subtopics)
Manage data > Data types > Tables > Joining tables by spatial query (and all subtopics)
Topology
Topology is a collection of rules and relationships that define the coincidence between point, line, and polygon features. You can create a topology to preserve the spatial relationships between features in your data. You can also use topology tools to validate and fix any potential errors. Topology includes rules that help ensure data quality; for example, you can set topology rules that will help you minimize gaps or overlaps among coincident features or simultaneously edit features that overlap or touch.
Two types of topology are supported in ArcGIS: map topology and geodatabase topology. Map topology is available at all license levels, whereas geodatabase topology requires an ArcGIS Standard or Advanced license. Map topology does not require any setup and can be used to maintain the coincidence, covering, and crossing of any visible features in your maps. Geodatabase topology is stored as part of a feature dataset and includes a collection of rules and editing tools that enable your geodatabase to accurately model the geometric relationships between features in one or more of the participating feature classes.
ArcGIS includes geoprocessing tools that you can use to build, analyze, manage, and validate topologies. For example, you can use tools in the Topology toolset to build and load data into a topology. Then you can define rules to edit and maintain the participating features. Once these rules are in place, you can run a validation against the topology, and ArcGIS will identify areas that require edits or that have broken your rules. If a predefined fix is available, you can quickly fix the error using functionality in the user interface; if not, you can modify the features using modify tools and can validate the areas again to ensure that your changes have fixed the error.
Prepare
These topics in the documentation provide details about topology.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Edit geographic data > Modify topology >Introduction to editing topologyMap topologyGeodatabase topology (and all subtopics)
Gain a thorough understanding of these ArcMap Help topics:
Practice
Take these web courses to get more hands-on experience:
Getting Started with the Geodatabase
Skills check-in
Now that you have explored these concepts, it is time to check in! This is not an exhaustive list of topics that are covered on the exam, but it references the types of tasks a qualified candidate should be able to perform. If there is anything you cannot confidently do, review those concepts until you can.
I can:
Given requirements for a specific project, design a file geodatabase to support the project (for example, the behavior or functionality of the geodatabase, types of datasets).
Determine the set of simple features, tables, or complex feature types necessary to support a use case.
Given required relationships, design and implement key fields and relationship classes with required cardinality.
Determine the objects participating in topologies, networks, and routes.
Create and manage complex data types (for example, topology, network dataset, annotations, routes).
Generate domains from tables of clerical research.
Select appropriate data formats for an intended use
A geodatabase is the ideal place to store simple vector, raster, and tabular data, but it is not limited to simple data. Geodatabases are also designed to support complex data elements that you can use to manage high-resolution data, massively large point datasets, and large collections of high-resolution imagery. For example, a geodatabase is an ideal place to store 3D surfaces or multispectral and multidimensional data. This section covers data formats that you can use to manage massively large point datasets and large collections of high-resolution imagery. This skill has two parts: (1) managing high-resolution point data and (2) mosaic datasets.
Managing high-resolution point data
One of the most common data formats used for storing and visualizing high-resolution point data is LAS. LAS is an American Society for Photogrammetry and Remote Sensing (ASPRS)–derived open file format used for the storage and interchange of lidar data. Lidar data gives GIS professionals access to a densely sampled point cloud that reflects the earth’s surface at extremely high resolutions. ArcGIS provides LAS file support using LAS datasets, mosaic datasets, and terrain datasets.
A LAS dataset gives you access to large volumes of lidar data by storing a reference to source files. This functionality allows you to view the data in its native format, offering support for several thousand LAS files at a time. Because the data is referenced rather than stored, it can be constructed quickly and can be used to provide a quick look at the statistics and extent of the participating LAS files. LAS datasets can also be converted into a TIN-based surface for visualization, making them a great complement to your terrain dataset workflows. For example, you could use a LAS dataset to perform a quality check on your lidar data before migrating it into a terrain dataset. LAS datasets require the ArcGIS 3D Analyst™ or ArcGIS Spatial Analyst™ extension, or an ArcGIS Desktop Standard (or higher) license.
A terrain dataset is a multiresolution, TIN-based surface that can be used to store your lidar data. Unlike LAS datasets, terrain datasets do not provide direct support for LAS files. Instead, a terrain resides in a geodatabase and is created as part of a feature dataset that includes one or more multipoint feature classes. Terrains are advantageous because they have no size limit and they can be given rules that drive their behavior. For example, you can specify the effect of participating features on surface definition or decide whether features will be visible at different map scales. Another strength of terrain datasets is that they give you the ability to integrate your 3D-based mass point observations with other data sources, such as 3D features captured using stereo photogrammetry. After your terrain datasets are created, you can use them to create contours, generate line-of-sight products, and create profile graphs.
Prepare
These topics in the documentation provide details about managing high-resolution point data.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Data types > Lidar and LAS dataset >What is a LAS dataset?The LAS dataset layer in ArcGIS Pro
Help > Data > Data types > Terrain datasets (and all subtopics)
Gain a thorough understanding of these ArcMap Help topics:
Manage Data > Data types > LAS dataset > What is a LAS dataset?
Mosaic datasets
ArcGIS allows you to organize, store, and manage raster data as a raster dataset, a mosaic dataset, or a raster catalog. Of these options, a mosaic dataset is the recommended data model for most use cases. Mosaic datasets are stored in geodatabases; they consist of a collection of raster datasets stored as a catalog; the participating raster datasets can be viewed as a single mosaicked image or as individual images. All mosaic dataset data is referenced from its original storage location, so data can remain in its original format and is not restricted by the different projections, resolutions, pixel depths, or numbers of bands that exist. Mosaic datasets support processing on the fly using raster functions and provide support for LAS datasets. Adding LAS datasets to your mosaic dataset allows you to use 3D Analyst tools, such as the Slope tool or the Viewshed tool, and gives you the ability to use your lidar data as a DEM.
You can create mosaic datasets in ArcGIS using the Create Mosaic Dataset and Create Referenced Mosaic Dataset tools. The Create Mosaic Dataset tool allows you to add your own data and to modify data properties and functions on a per-raster basis. For example, you can use the product definition property to create custom product definitions that define the number of bands, band order, and wavelength ranges of imagery collected by various satellite imagery platforms. The Create Referenced Mosaic Dataset tool creates read-only mosaics that reference existing mosaic datasets or raster catalogs. After you have created a mosaic dataset, you can add rasters to it using the Add Rasters To Mosaic Dataset tool and specifying the Raster Type parameter. Doing so enables the software to recognize and define any processing that needs to be applied before you add the data to the mosaic dataset.
Prepare
These topics in the documentation provide details about mosaic datasets.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Data types > Imagery and raster > Image management >Mosaic datasetsRaster products and raster types
Help > Data > Data types > Imagery and raster > Multidimensional >An overview of multidimensional raster dataAn overview of multidimensional data in a mosaic dataset
Help > Data > Data types > Imagery and raster > Workflows > Create a mosaic dataset
Tool Reference > Tools > Data Management toolbox > Raster toolset > Mosaic Dataset toolset >Add Rasters To Mosaic DatasetCreate Mosaic DatasetCreate Referenced Mosaic Dataset
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Data types > Raster and images > Introduction > Essential raster data vocabulary
Manage data > Data types > Raster and images > Supported raster data > Multidimensional raster types
Tools > Tool reference > Data Management toolbox > Raster toolset > Mosaic Dataset toolset >Add Rasters To Mosaic DatasetCreate Mosaic DatasetCreate Referenced Mosaic Dataset
Practice
Take these web courses to get more hands-on experience:
Managing Raster Data Using ArcGIS
Skills check-in
Now that you have explored these concepts, it is time to check in! This is not an exhaustive list of topics that are covered on the exam, but it references the types of tasks a qualified candidate should be able to perform. If there is anything you cannot confidently do, review those concepts until you can.
I can:
Identify data formats for surfaces, or multispectral applications, simple feature, multidimension, LAS data, external formats (CAD).
Compare a variety of geodatabase or external storage types (for example, elevation raster, LAS datasets, terrain datasets).
Create a mosaic dataset from raster data or LAS data.
Create derived raster products.
Create and maintain attachments.
Given a task, determine the data, settings, and parameters for creating a complex dataset
ArcGIS supports the creation of complex datasets that can be used to perform network analysis on both transportation and utility networks. Networks can be used to help plan routes for a delivery fleet or to calculate vehicle drive times while including impedance factors such as street direction and traffic volume. This section describes two ways to use networks in ArcGIS. This skill consists of two parts: (1) network datasets and (2) geometric networks.
Network datasets
Network datasets are used to model networks that allow bidirectional travel or facilitate travel by agents who can make decisions about how to travel across the network (such as a delivery driver in a transportation network). After a transportation network has been modeled, it can be used to optimize route planning and streamline business processes. For example, a parcel shipping company might use a network dataset and tools in the ArcGIS Network Analyst extension to calculate the least-cost path (where least-cost is defined as shortest travel time) from a warehouse to a customer’s home.
Network datasets are made up of point and line features, known as network elements, that define the physical characteristics of the network. The topological relationships of these features are enforced by logic that is built in to the network dataset. These network elements establish connectivity and control navigation over the network. When you create a network dataset, you identify line and point features that will create your network’s basic structure as edges and junctions. Network datasets may also include turns, which are used to model restrictions in the network. The elements are then used to model and describe connectivity. Connectivity tells the network how your edges and junctions are formed and describes which network sources interconnect. In a network dataset, the connectivity model is discovered on demand and is refreshed with a network build. Connectivity is important for accurate analysis results and can be used to help you model multimodal transportation systems in areas with a complex transportation infrastructure. After you have modeled connectivity, you can use network attributes to give ArcGIS additional information about the network dataset, leading to more accurate analysis results. For example, a cost attribute can be used to measure and model factors that can impede travel, such as travel time or traffic volume at a given time of the day.
Reminder
ArcGIS Pro 1.4 provides limited functionality for creating and working with network datasets. Please refer to the ArcGIS Pro Help links for a detailed discussion of the current state of network datasets and network analysis in ArcGIS Pro.
Prepare
These topics in the documentation provide details about network datasets.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Analysis and geoprocessing > Network Analyst > Network datasets > What is a network dataset?
Gain a thorough understanding of these ArcMap Help topics:
Extensions > Network Analyst > What is the ArcGIS Network Analyst extension?
Extensions > Network Analyst > Essential ArcGIS Network Analyst extension vocabulary
Extensions > Network Analyst > Network datasets >What is a network dataset?Designing the network datasetNetwork elementsUnderstanding connectivityUnderstanding network attributes
Extensions > Network Analyst > Network datasets > Building and editing the network dataset > Editing network datasets >Ways to edit network datasetsAdding network sourcesModifying connectivity
Geometric networks
Geometric networks give ArcMap users the ability to model directed-flow networks, where each edge has a fixed direction of flow (such as the flow of electricity through a utility network). A geometric network consists of junctions, such as a valve, and simple or complex edges. These features are sourced by feature classes in a feature dataset in a geodatabase. Simple edges allow a resource to enter through only one end of the edge and to exit through the other. An example of a simple edge is a water lateral. Complex edges allow resources to enter and exit through the ends and through additional junctions along their length. An example of a complex edge is a water main that is connected to multiple water laterals along its length.
Reminder
ArcGIS Pro does not offer geometric network support. At ArcGIS Pro 2.x, the new utility network has assumed the management of utility and telecom networks in ArcGIS.
Geometric networks are created in the ArcMap Catalog window or using tools in the Geometric Network toolset. The Geometric Network tools can be used to manage and analyze geometric networks. For example, you can use these tools to perform a variety of tracing functions, including downstream trace, upstream trace, isolation trace, and path trace. Geometric network analysis can be affected by using attribute weights that represent the cost of traversing an edge in the network. They can also incorporate the use of disabled features that represent disconnected features or can temporarily disable features without requiring you to delete them. This functionality is useful in cases in which a temporary power outage occurs on one portion of a utility network. As you edit a geometric network, ArcGIS maintains connectivity between the network’s features.
Prepare
These topics in the documentation provide details about geometric networks.
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Data types > Geometric networks >What are geometric networks?A quick tour of geometric networksEssential geometric networks vocabulary
Manage data > Data types > Geometric networks > Creating and managing geometric networks
Practice
Complete these tasks to get more hands-on experience:
Skills check-in
Now that you have explored these concepts, it is time to check in! This is not an exhaustive list of topics that are covered on the exam, but it references the types of tasks a qualified candidate should be able to perform. If there is anything you cannot confidently do, review those concepts until you can.
I can:
Create a geometric network, geodatabase topology, geodatabase terrain, and transportation networks.
Determine the role of the feature classes’ participation in the network and determine the role of the feature dataset in the network.
Update schema changes for the geometric network.
Determine the components of a network dataset (for example, network weights, connectivity rules, cluster tolerance).
Determine the appropriate feature classes to participate, rules to apply, and feature dataset properties.
Determine the role of the feature datasets for complex datasets (for example, terrains, topology).
Given a task, determine the data, settings, and parameters for creating an address locator
ArcGIS gives you the ability to model the real world using tabular data. The points in your tables can be converted into points on a map through geocoding. Geocoding allows you to take your addresses and custom place names and display them as features on a map. A central component of the geocoding workflow is the address locator. This section explores the geocoding workflow and emphasizes methods for creating and sharing address locators. This skill has two parts: (1) creating an address locator and (2) sharing an address locator.
Creating an address locator
ArcGIS supports geocoding and place-name searches in both desktop and web environments. Successful geocoding requires an understanding of the geocoding workflow. The geocoding workflow consists of these steps:
1 Build or obtain reference data.
2 Determine address locator style.
3 Build an address locator.
4 Locate addresses.
5 Publish or maintain your address locator.
The address locator is particularly important to the geocoding workflow because it contains the parameters and matching rules that tell ArcGIS how to match your input data to locations in your reference data.
Before creating an address locator, you must determine which address locator style to use. The address locator style specifies properties and parsing grammar that determine acceptable input, so it is important to choose a locator style that closely matches the input format of your address and reference data. After you choose an address locator style and prepared reference data, you can build an address locator using geoprocessing tools in the Geocoding Tools toolbox. If you need to match your addresses against multiple locators, you can create a composite locator. A composite locator combines two or more individual address locators; the software chooses from among them to find the best match. After you have created your address locator, you can use it to search for individual records or batch geocode a table of addresses.
Prepare
These topics in the documentation provide details about creating an address locator.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Data types > Geocoding > Get started > What is geocoding?
Help > Data > Data types > Geocoding > Prepare for geocoding (and all subtopics)
Help > Data > Data types > Geocoding > Create a locator (and all subtopics)
Tool Reference > Tools > Geocoding toolbox > An overview of the Geocoding toolbox
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Geocoding > Introducing geocoding > What is geocoding?
Manage data > Geocoding > Introducing geocoding > Understanding geocoding > The geocoding workflow
Manage data > Geocoding > Introducing geocoding > Preparing for geocoding (and all subtopics)
Manage data > Geocoding > Introducing geocoding > Building an address locator (and all subtopics)
Tools > Tool reference > Geocoding toolbox > An overview of the Geocoding toolbox
Sharing an address locator
If you need to share an address locator with other ArcGIS users, you can share it as a locator package or publish it to the web. You can create a locator package (.gcpk) using the Package Locator tool and can share it as a local file or in an ArcGIS portal. If you want to share your locator for use in web maps or web apps, you can publish it as a geocode service. When you publish an address locator as a geocode service, you can apply several helpful capabilities, as described in this table.
Optional capabilities for geocode services
Reminder
ArcGIS Pro 1.4 cannot publish directly to ArcGIS Server. You must be logged in to ArcGIS Enterprise 10.5 or later with at least one federated server and Publisher or Administrator privileges to publish a locator in ArcGIS Pro 1.4.
Prepare
These topics in the documentation provide details about sharing an address locator.
Gain a thorough understanding of these ArcGIS Pro Help topics:
Help > Data > Data types > Geocoding > Share locators (and all subtopics)
Gain a thorough understanding of these ArcMap Help topics:
Manage data > Geocoding > Introducing geocoding > Sharing your address locator >About sharing an address locator as a locator packageAbout sharing your address locator as a geocode service
