Working with Geodatabase Domains and Subtypes in ArcGIS
Getting Started with Geodatabase Topology
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 > Imagery and raster
