Geodatabase Essentials Presentations

Following up on our UC presentations post, Brent and I are posting the tech workshop presentations we gave (with other members of the geodatabase team) down in San Diego at this year's user conference. You can check out the presentations in PDF format by following the links below.

Geodatabase Essentials Part I – An Introduction to the Geodatabase
Geodatabases Essentials Part II – An Introduction to ArcSDE Geodatabases

If these slides are not enough, you can order all the technical workshop recordings through Source of Knowledge here.

Geodatabase Replication - Additional info & Patch

This post was written by Heather McCracken and Gary MacDougall, both product engineers on the geodatabase team specializing in geodatabase replication

We just wanted to give you a heads up that there are a number of resources available which provide additional information on geodatabase replication. These include white papers, podcasts and technical articles. We’ve been keeping a knowledge base article that lists these helpful resources. This is a living document, so we’ll be continually updating it as new resources become available. You can find the article here

Also, there is a new patch for replication available for 9.2’s service pack 6. The patch addresses issues when synchronizing data where there are relationships that use the objectID column as the primary key. You can download the patch at the following location:

ArcGIS (Desktop, Engine, Server) 9.2 Synchronizing with Objectid Based Relationship Classes Patch

Customizing Table Sorting in the Geodatabase

This post was written by James MacKay, a product engineer on the geodatabase team who also played the leading role in the "Programming with the geodatabase API" sessions at this years user conference.  

In ArcGIS there are a number of different ways a column within a table can be sorted. For the majority of use cases the default sorting options provided in ArcGIS will work fine. In a handful of situations, however, the default sort options do not sort the information in a logical way.

Consider the following case, a table containing civic address numbers with suffixes in a string: 

The default column sorting will arrange the values in alpha-numeric order. For civic addresses this doesn't really make sense. To get around this a table sorting can be programmatically customized.

Should I load my raster data into a geodatabase?

I noticed there were a lot of raster related questions at the user conference this year. People mainly wanted to know the advantages of loading raster data into a geodatabase, and generally how to manage their raster data. So I talked to Simon Woo on the raster team about it and he put together this list of pros and cons for loading raster data into a geodatabase (ArcSDE or File) as opposed to keeping the raster data in a file format outside of the geodatabase.

Note: This post only applies to the ArcSDE and file geodatabase. A personal geodatabase does not offer these same advantages.

Pros:
Fast data access
The geodatabase stores your data in blocks, which allows ArcGIS to access only the blocks of data that you need to use. Once loaded, this format allows ArcGIS to access your data very quickly.

Multi-user access
The geodatabase allows multi-user access to data whereas most file formats are not meant for multi-user operations.

Compression
Raster data can be compressed as it is being loaded into a geodatabase. Various types of compression schemes can be used including LZW, JPEG, and JPEG 2000. Note: If your file format is already compressed with a high compression factor, then the geodatabase compression may not be as highly compressed.

Better handling of NoData values
The geodatabase stores your Nodata pixels as a bit-mask rather than a value in the raster dataset. This means that you don’t need to use a pixel value as a place-holder for your NoData values like you do in most file formats.

Security (ArcSDE only)
Since your DBMS will require a user name and password, you can store your data in an ArcSDE database and know that only authorized users can access your data.

Cons:
Lack of third-party software support
Not all third party programs will allow an ArcGIS geodatabase to be used in conjunction with their software. This means that you are limited to the software packages that can access your data. This should be one of the considerations before you store your raster data in a geodatabase.

Lower compression than some file formats
The geodatabase allows your data to be stored with compression; however there is compression software available that can more highly compress your data – such as wavelet compression technology. For these datasets the file format may take up less storage space than the compression used by the geodatabase.

Loading Time
Since the data needs to be converted to a geodatabase block format, it takes time to load your data into the geodatabase. The larger your data, the more time it will take to load. Thankfully you only need to load your data into the geodatabase once.

For more information check out the help topic Why store rasters in a geodatabase, which goes into similar details as well as gives a comparison of storing raster datasets and raster catalogs.

I'm adding a few more useful raster help topics to this post based on the comments and feedback we're getting. The first two are case studies on building large raster datasets and storing raster datasets. Another good topic is loading large raster datasets into ArcSDE.

2008 User Conference Presentations - Geodatabase Editing Workflows: Parts 1 & 2

The geodatabase editing workflow presentations are a good way to get introduced to editing in a geodatabase and become familiar with editing workflows and processes designed to meet the needs of GIS professionals.

Like the Geodatabase Essentials presentations Geodatabase Editing Workflows is split into two parts: An Introduction and Advanced.

Here’s what Derek Law had to say when I asked him about the scope of the Introduction session:

“In our Geodatabase Editing Workflows session Kasia and I will be covering a range of introductory editing topics. We’ll be talking about the different editing environments available within an ArcSDE geodatabase. That is to say we’ll be explaining non-versioned editing, versioned editing, and versioned editing with the option to move edits to base. We’ll be tackling these in kind of a what happens behind the scenes approach, and also look at workflow considerations and how to manage data changes. Our session introduces the major concepts and lays down the foundation for Tony and Rob’s session on more advanced geodatabase editing workflows.”

As a co-presenter for the second part of the presentations, Rob Rader had this to say about the Advanced session:

“In our follow up to Derek and Kasia’s tech workshop Tony, Tom, and I will be expanding on the editing topics that they introduced with more advanced geodatabase editing workflows. We’ll be covering non-versioned editing workflows and look into some more complex functionality such as geodatabase archiving and replication. From there we’ll have a discussion on versioned editing, how to deal with conflicts, and offer some workflow recommendations. I would suggest attending this session if you find yourself implementing more complex workflows or maybe you feel you need to. It’s a good way to get a look at some recommended workflows and see some key versioning, archiving and replication techniques.”

Here are the outlines for their sessions:

Geodatabase Editing Workflows – An Introduction
Derek Law; Kasia Tuszynska

Room 6C
Wednesday, August 6 – 8:30am – 9:45am
Thursday, August 7 – 1:30pm – 2:45pm

Goals of the workshop:

• Introduce Editing Environments: Non Versioned Editing, Versioned Editing, Move to base Editing
• Define the architecture of Versioned Editing
• Introduce Versioning Management: Reconcile, Post, Conflict Resolution
• Discuss Compress

Major topics covered:

• What is a difference between the three versioning environments?
• What do words like: version, state, state lineage mean?
• What are A and D tables?
• How to post and reconcile versions
• What are the options when resolving editing conflicts?
• What is the purpose of a compress?

Geodatabase Editing Workflows – Advanced
Tom Brown; Robert Rader; Tony Wakim

Room 6C
Wednesday, August 6 – 10:15am – 11:30am
Thursday, August 7 – 3:15pm – 4:30pm

Goals of the workshop:

• Explain Non-Versioned editing
• Address database transactions and data complexity
• High Level Review of Versioning
• Explain Geodatabase Archiving and Replication
• Discuss different database environments including: data models, and performance
• Resources

Major topics covered:

• How do database transaction isolation levels influence non-versioned editing
• In depth discussion of versioning topics including examples on when you would want to use each of the models
• Introducing Geodatabase Archiving and Replication at a high level
• Detailed discussion of the Geodatabase options and how they affect performance and functionality.
• Mixed editing environments and access by third party applications
• Performance and workflow management with Archiving and Replication

2008 User Conference Presentations – Geodatabase Essentials: Parts 1 & 2

The Geodatabase Essentials presentations are designed to introduce the main concepts integral to the geodatabase and its use.

Colin Zwicker and I will be presenting the first part, introducing the concept of the geodatabase and offering a high level overview of the datasets that can be contained within.

Colin elaborates: “The Geodatabase Essentials Part I tech workshop is geared towards introducing new users to what a Geodatabase is, what some of the features are, and why users would want to use them. The topics range from what types of Geodatabases are available to how some of the datasets apply Geodatabase business logic for added functionality. I’ll be walking through some demos to highlight a few of the key topics. The Geodatabase Essentials Part I will focus mainly on single user Geodatabases. We will introduce the concepts and build the foundation for the second installment, Geodatabase Essentials Part II, which will focus more on ArcSDE geodatabases and their functionality.”

Brent had this to say about the second part of the presentation:
“The goal of this session is to tell the ArcSDE geodatabase story. ArcSDE geodatabases are a very powerful technology and we think this session will go a long way in explaining what ArcSDE geodatabases are and how they can be used. The target audience for this session is anyone who is using or thinking about using ArcSDE geodatabases. The content will be given at a very high level as we have a number of low level sessions dealing with specific aspects of the enterprise geodatabase throughout the week.”

Here are the outlines for the two presentations to give you an idea of what we’ll be talking about down in San Diego.

Geodatabase Essentials Part I – An Introduction to the Geodatabase
Colin Zwicker; Jonathan Murphy

Goals of the workshop:

• Explain what a geodatabase is and why you would want to use it
• Describe data management via the geodatabase
• Demonstrate geodatabase functionality
• Explore the geodatabase data model

Major topics covered:

• Introduction to the geodatabase: the data storage and data management framework for ArcGIS
• Benefits of the geodatabase: Storing data in a DBMS, it supports open standards, implement business logic and data integrity, allow multi-user editing and data distribution.
• Geodatabase data management: leverages RDBMS architecture, spatially continuous datasets, version management, supports multiple data sources
• Types of geodatabases: Explaining the differences between personal, file and ArcSDE geodatabases and the benefits of each type

Each of the following geodatabase elements will also be introduced:

• Objects and object classes: entities with properties and behavior, tables with a unique ObjectID column
• Features and feature classes: An object class that models spatial features, has an ObjectID and a Shape column
• Feature datasets: container for other datasets with the same spatial reference
• Domains: ensure attribute integrity, there are two types – Range and Coded
• Subtypes: separate feature classes into like groups
• Relationship classes: create associations between two object classes
• Annotation: create labels, text and other graphics on the map
• Dimension features: display distances and measures on the map
• Geometric Networks: model network systems, trace network flows
• Network datasets: model complex, multimodal transportation datasets
• Terrains: dataset for modeling 3D surfaces and massive point datasets
• Topology: manage a set of features that share geometry or spatial coincidence, define integrity rules and constraints for associated feature classes
• Raster: import imagery, mosaic images, create raster catalogs
• XML Export / Import: transfer schema and/or features, export a subset of a geodatabase, import into an existing geodatabase

Geodatabases Essentials Part II – An Introduction to ArcSDE Geodatabases
Craig Gillgrass; Gary MacDougall; Brent Pierce
Room 4
Wednesday, August 6 - 8:30am – 9:45am
Thursday, August 7 - 8:30am – 9:45am
Friday, August 8 - 8:30am – 9:45am

Goals of the workshop:

• Compare and contrast the different types of geodatabases, focusing on ArcSDE geodatabases
• Provide a clear explanation of ArcSDE geodatabases including when to consider their use and what advantages they provide
• Explain ArcSDE specific functionality, focusing on versioning, archiving and geodatabase replication
• Review best practices for each of these areas
• Discuss some of the functionality in ArcGIS 9.3 for ArcSDE geodatabases

Major topics covered:

• What are ArcSDE Geodatabases
• Versioning
• Introduce versioning and its basic concepts
• How does multi user editing work with versioning
• Using reconcile and post
• Archiving
• Introduction and description of how it works
• Problems that archiving can help solve
• Geodatabase Replication
• Define geodatabase replication and describe use cases where it can be used
• The types of replication available
• Creating and synchronizing replicas
• Best practices for creation, synchronizing and maintaining replicas
• What’s new in 9.3 for the geodatabase

2008 User Conference - Geodatabase Presentations

The 2008 ESRI International User Conference is roughly three weeks away and our team has been preparing technical workshops and demo theatres to present down in San Diego. Over the next few weeks we’ll be posting about these sessions so you can get a closer look and have an idea of what to expect.

Here is a list of the presentations our team is offering at this year’s UC:

Tech Workshops

Fundamentals
Geodatabase Essentials Part I – An Introduction to the Geodatabase
Jonathan Murphy, Colin Zwicker
Room 6C
  Tuesday, August 5 - 8:30am – 9:45am
  Wednesday, August 6 - 1:30pm – 2:45pm
Room 10
  Friday, August 8 - 8:30am – 9:45am

Geodatabases EssentialsPart II – An Introduction to ArcSDE Geodatabases (New)
Craig Gillgrass; Gary MacDougall; Brent Pierce
Room 4
Wednesday, August 6 - 8:30am – 9:45am
Thursday, August 7 - 8:30am – 9:45am
Friday, August 8 - 8:30am – 9:45am

Geodatabase
Geometric Networks in the Geodatabase
Craig Gillgrass; Erik Hoel
Room 3
Tuesday, August 5 - 8:30am – 9:45am
Wednesday, August 6 – 1:30pm – 2:45pm

Managing Distributed Data with Geodatabase Replication
Gary MacDougall; Heather McCracken
Room 6D
Tuesday, August 5 – 3:15pm – 4:30pm
Thursday, August 7 – 10:15am – 11:30am

Using SQL and Spatial Data Types with the Geodatabase
Shannon Shields; Kasia Tuszynska; Juliette Gutierrez
Room 4
Wednesday, August 6 - 10:15am – 11:30am
Thursday, August 7 – 3:15pm – 4:30pm

Topology in the Geodatabase
Erik Hoel; Doug Morgenthaler
Room 6C
Tuesday, August 5 – 1:30pm – 2:45pm
Thursday, August 7 – 8:30am – 9:45am

Working with ESRI's Spatial Data Type for Oracle
Tom Brown, Kevin Watt
Room 4
Wednesday, August 6 - 12:00pm - 1:00pm

Geodatabase Administration
Administration for Oracle – An Introduction
Travis Val; James Gough
Room 4
Tuesday, August 5 - 8:30am – 9:45am
Wednesday, August 6 – 1:30pm – 2:45pm

Administration for Oracle – Advanced
Robert Rader; Travis Val
Room 4
Tuesday, August 5 – 10:15am – 11:30am
Wednesday, August 6 – 3:15pm – 4:30pm

Administration for SQL Server – An Introduction
Shannon Shields; Wendy Wallace
Room 4
Tuesday, August 5 – 1:30pm – 2:45pm
Thursday, August 7 – 8:30am – 9:45am

Administration for SQL Server – Advanced
Shannon Shields; Tony Wakim
Room 4
Tuesday, August 5 – 3:15pm – 4:30pm
Thursday, August 7 – 10:15am – 11:30am

Administration for PostgreSQL – An Introduction           
Kasia Tuszynska; Derek Law
Room 4
Wednesday, August 6 – 12:00pm – 1:00pm

Administration for IBM Databases – An Introduction           
Chris Bosch; Donna Cranfill; David Adler
Room 4
Tuesday, August 5 – 12:00pm – 1:00pm

Enterprise Geodatabase Tuning – Tips and Tricks
Mark Harris
Room 6D
Tuesday, August 5 – 1:30pm – 2:45pm
Thursday, August 7 – 8:30am – 9:45am

Editing
Geodatabase Editing Workflows – An Introduction
Derek Law; Kasia Tuszynska
Room 6C
Wednesday, August 6 – 8:30am – 9:45am
Thursday, August 7 – 1:30pm – 2:45pm

Geodatabase Editing Workflows – Advanced
Tom Brown; Robert Rader; Tony Wakim
Room 6C
Wednesday, August 6 – 10:15am – 11:30am
Thursday, August 7 – 3:15pm – 4:30pm

Raster Data
Working with Raster Data in ArcGIS
Simon Woo, Robert Berger, Hong Xu
Room 6D
Tuesday, August 5 - 8:30am – 9:45am
Wednesday, August 6 – 1:30pm – 2:45pm

Managing Raster Data in Geodatabase
Mark Harris, Qian Liu, Dan Meeks
Room 6D
Tuesday, August 5 – 10:15am – 11:30am
Wednesday, August 6 – 3:15pm – 4:30pm

Analysis and Geoprocessing
Linear Referencing: An Introduction
Derek Law and Heather McCracken
Room 9
Tuesday, August 5 – 1:30pm – 2:45pm
Thursday, August 7 – 3:15pm – 4:30pm

Demo Theatres

For more general information about the conference you can visit the main UC page.

There is also a UC Blog which has been posting lots of tidbits and info regarding the conference.

Direct connections to ArcSDE geodatabases

This post was written by Kim Peter, a product engineer on the geodatabase team, and is a follow up to her post on Connections to 9.3 Geodatabases

There are two types of connections you can make to ArcSDE geodatabases: direct connections or connections through an ArcSDE service. This post deals with making direct connections to ArcSDE geodatabases with ArcGIS clients, where the ArcGIS client and ArcSDE geodatabase are from different releases.

You may have heard that to make direct connections from an ArcGIS client, you no longer need to have the client software and the geodatabase at the same release. This is true for ArcGIS 9.2 service pack 5 (SP5) or SP6 clients making a connection to an ArcSDE 9.3 geodatabase and for ArcGIS 9.3 clients making direct connections to an ArcSDE 9.0, 9.1, 9.2, or 9.3 geodatabase.

Here’s some information you need to successfully set up these inter-release direct connections.

• You must perform a separate installation to get the direct connect drivers necessary to make these connections.
• The setup to obtain the 9.0, 9.1, and 9.2 direct connect drivers is called ArcGIS Pre-9.3 GDB Direct Connect Setup and is included on your 9.3 client media along with an installation guide.

• The setup to obtain the 9.3 drivers needed to make a direct connection from an ArcGIS 9.2 SP5 or SP6 client to an ArcSDE 9.3 geodatabase must be downloaded from the ESRI support site Patches and Service packs download page. This setup is called ArcGIS 9.3 GDB Direct Connect for 9.2 Clients Setup. An installation guide for this setup is also provided with the download.

• The ArcSDE 9.0, 9.1, or 9.2 geodatabase to which you are making a direct connection must have the latest service packs applied. Check the ESRI support site’s download page for the latest service pack for each release.

• Direct connections from an ArcGIS 9.3 client to an ArcSDE 9.0, 9.1, or 9.2 geodatabase for Informix is not supported.

• Direct connections from an ArcGIS 9.3 client to an ArcSDE 9.0 geodatabase for Oracle 8i are not supported.

• When you connect to a geodatabase on an ArcSDE database server (an ArcSDE geodatabase for SQL Server Express), you always make a direct connection. Be aware that the upgrade procedure for ArcSDE geodatabases for SQL Server Express will differ depending on whether or not you have the 9.2 direct connect drivers installed. See Upgrading geodatabases on ArcSDE database servers in the help to see how to upgrade these geodatabases. (Note that at 9.3 final release there is a bug that will prevent you from upgrading the geodatabase if you have the 9.2 direct connect drivers installed. If you want to upgrade the geodatabase, do it from an ArcGIS 9.3 client that does not have the 9.2 direct connect driver installed.)

• You should also read the help topics, Compatibility between clients and geodatabases and Client and geodatabase compatibility for additional notes and restrictions on interoperable releases. (The second topic has information on file and personal geodatabases as well as ArcSDE geodatabases.)

For information on connections, see An overview of ArcSDE geodatabase connections and Properties of a direct connection.

9.3 Webhelp now publically available

The 9.3 Web help is now publically available since the login requirement was lifted yesterday. The web help is a great resource for up to date information. Even after the product is released the web help gets updated weekly with content and corrections.

Check out the What’s new in 9.3 section to see what new functionality 9.3 has to offer.

As for geodatabase related documentation, there are lots of new topics and content, such as:

Merge geometries
Using the Version Changes command
Mosaicking raster datasets
Color correcting using raster data
Raster Clip geoprocessing tool
ArcSDE connection syntax
Compatibility between clients and geodatabases
Inside a geodatabase in PostgreSQL

The Resource Centers will also be publically available soon, we’ll keep you posted on those.

Connections to 9.3 geodatabases

This post was submitted by Kim Peter who is a product engineer and technical writer on the geodatabase development team

In order to take advantage of new functionality added to the geodatabase in a release of ArcGIS, the geodatabase must be upgraded.  This will be the case with ArcGIS 9.3, as we’ve added new functionality to terrains and network datasets:

• Creating a terrain with the new window size pyramid format.
• Creating a network dataset with an attribute that uses the new global turn delay and network function evaluators.

To see how you can upgrade a geodatabase to the 9.3 release, consult the help topics Upgrading file and personal geodatabases, Upgrading geodatabases on database servers, and Upgrade summary for ArcSDE geodatabases.

However, this doesn’t mean that you need to upgrade your ArcGIS 9.3 clients to 9.3 in order to connect to and use 9.3 geodatabases. You will still be able to connect from a client with ArcGIS 9.2 SP5 or later service pack to a 9.3 geodatabase. For example, if a coworker sends you a file geodatabase he or she created with an ArcGIS Desktop 9.3 client, you can open and edit it in your ArcGIS 9.2 SP5 client.

As with previous geodatabase upgrades, if you decide not to upgrade your geodatabases but you do install the 9.3 release of the client software, you will be able to connect from the 9.3 client to 9.2 geodatabases. If you don’t need to take advantage of the new functionality for terrains and network datasets, the geodatabase upgrade is optional and not required.

Be aware, though, there are a couple of caveats to these inter-release connections.

They are as follows:

• You have to have at least service pack 5 applied to the client application to be able to connect and edit from a 9.2 client to a geodatabase that has been upgraded to the 9.3 release.

• If connecting from a 9.2 SP5 or SP6 client to a 9.3 geodatabase, you will have all the 9.2 functionality available to you.

• If connecting from an ArcGIS 9.3 client to a geodatabase that has not been upgraded from 9.2, ArcGIS will prevent you from using 9.3 functionality in the geodatabase.

• If making direct connections from the client application to an ArcSDE geodatabase, additional drivers need to be installed. This configuration will be discussed in a future blog post.

Road Ahead - Extending One-Way Replication

We’ve extended the one-way replication model at 9.3 to include file and personal geodatabases. So now when you are creating a one-way replica, the destination doesn’t have to be an ArcSDE geodatabase, it can also be a file or personal geodatabase.

This opens up a host of new replication scenarios since the child replica doesn’t need to be versioned or have SDE technology. This will also leverage one-way implementations such as production-publication scenarios or mobile users working in the field.

Here are a few more sources of information on replication topics:

• Gary MacDougal and I put together a whitepaper detailing common scenarios for replication called An Overview of Distributing Data with Geodatabases.

• The help topic Working with geodatabase replication offers a good walkthrough of implementing replication with links to other essential replication topics.

• Also, a new video in the 9.3 help system offers an example of how to create and synchronize replicas in a connected environment.

Geodatabase Essentials - Archiving

Geodatabase archiving provides a mechanism for capturing and managing a record of your edits as features and rows are updated over time. This record is automatically updated as edits are saved and is available for query and analysis. This is handy when you want to go back and see how a feature has changed over time, see how a feature looked at a certain point in time, see how a certain area may have once looked, etc…

Archiving supports the complete geodatabase data model so topologies, geometric networks, feature datasets, relationship classes, tables and feature classes can all participate.

So here’s how it works:

First you enable all or a subset of your data as archiving. Only versioned data may be archiving enabled though, so you may have to first register your data as versioned. When the data has archiving enabled a class is associated with the original class known as the archive class. It is this archive class that maintains a record of the modifications made to the original data. The archive class has the same name as the original data, but with an "_H" appended on to the end. For example, if a feature class named "Roads" had archiving enabled on it, the archive class would be named "Roads_H".

What’s nice about archiving is that any changes made to a archiving enabled class are recorded automatically. It’s not something that is added to your workflow that you have to remind yourself to do after you make your edits. Once archiving is enabled on a class, any changes are automatically managed by the archive class.

A few new videos were added to the help system at 9.3 to demonstrate geodatabase archiving functionality. The videos offer examples on:

• Enabling archiving on a dataset
• Creating an historical marker and connecting to an historical version
• Using the geodatabase history viewer
• Working with the archive class

You can check the videos out HERE

Developer Tips - Using geodatabase methods with conformant array parameters in .NET and Java

 This post was written by geodatabase Product Engineer James MacKay. James works on the geodatabase development team and is responsible for a lot of the geodatabase SDK that is generated.

There are several methods in the Geodatabase API that use conformant arrays: these are C-style arrays that can be dimensioned at runtime. In most cases, if you see a method with a pair of related parameters – an integer indicating capacity (or something similar) and a pointer to an integer indicating values (or something similar) – it’s a safe bet that the method is looking for a conformant array.

A method with a conformant array parameter: ISelectionSet.AddList

Unfortunately, conformant arrays and Interop don’t jive… although they may work occasionally, eventually they’re going to cause problems. There are two workarounds: the GeoDatabaseHelper class and GEN interfaces.

The GeoDatabaseHelper class implements two interfaces, IGeoDatabaseBridge and IGeoDatabaseBridge2, which implement methods that can’t be used in a straightforward way through Interop. Three of the more common methods are IFeatureClass.GetFeatures, ISelectionSet.AddList, and ISelectionSet.RemoveList. The workarounds are IGeoDatabaseBridge.GetFeatures, IGeoDatabaseBridge2.AddList, and IGeoDatabaseBridge2.RemoveList, respectively.

GEN interfaces are identical to the interfaces with methods that use conformant arrays, but with the array type defined as SAFEARRAY instead of conformant arrays; they are implemented by the same classes. There are four GEN interfaces defined in the esriGeodatabase library: INetTopologyEditGEN, IForwardStarGEN, IUtilityNetworkGEN, and IEnumNetEIDBuilderGEN.

Five reasons why you should be using the File Geodatabase

Size

The database size is only limited by the available disk space. By default, individual tables and feature classes can be up to 1 TB. With the use of configuration keywords this can be expanded to 256 TB.

Versatility

Works on many different operating systems including Windows and UNIX (Solaris and Linux)

Speed

Provides excellent performance and scalability. For example, to support individual datasets containing well over 300 million features and datasets that can scale beyond 500 GB per file with very fast performance. The file geodatabase out performs shapefiles for operations involving attributes, and scales the data size limits way beyond shapefile limits. Through the use of an efficient data structure that is optimized for performance and storage, File Geodatabases use about one third of the feature geometry storage required by shapefiles and Personal Geodatabases.

Edit Model

The File Geodatabase uses an edit model similar to shapefiles, supporting one editor and multiple readers.  Each standalone feature class, table and feature dataset can be edited by different editors simultaneously but can only have one editor performing edits on them at any given time. This means that User A can edit the Roads Feature Class at the same time as User B edits the Parcels Feature Class.

Compression

File Geodatabases also allow users to compress feature classes and tables to a read-only format to reduce storage requirements even further. This reduces the Geodatabase’s overall foot-print on disk without reducing the performance.

Road Ahead - New workflow for mosaicking raster datasets

The following post was written by Simon Woo, a product engineer on the geodatabase team specializing in Raster support in the geodatabase.

Previous versions of ArcGIS have provided various mosaicking workflows.  We’ve tried to make the mosaicking experience better in each version, but have had varying feedback on performance, especially when outputting to a file format. 

Prior to ArcGIS 9.3, the workflow to create a mosaic was to create a raster dataset and then use the Workspace to Raster Dataset tool to populate the new dataset.

In ArcGIS 9.3, we have provided a new workflow to make your mosaicking experience faster. 

The new workflow is to:

• Create an unmanaged raster catalog with the Create Raster Catalog tool.
• Load all the raster datasets into the unmanaged raster catalog with the Raster to Geodatabase tool.
• Use the Raster Catalog to Raster Dataset tool to mosaic the datasets together. 

From the tests that we have run, this new workflow is considerably faster.  Below are a couple examples of comparison tests that have been run.   

Mosaic Test 1

Here’s the test data we used:
Type of data: 3-band
Input format: TIFF
Number of files: 20
Average file size: 38.8 MB
Output format: TIFF

Using the old workflow of creating a raster dataset and then using the Workspace to Raster Dataset tool, this data took 1 hour and 35 minutes to mosaic.

Here are the steps with the new workflow:

First create an unmanaged raster catalog.

This creates an unmanaged raster catalog. Now load the data into the new unmanaged raster catalog:

Now use the Raster Catalog to Raster Dataset tool to mosaic the rasters in the unmanaged raster catalog into a single raster dataset.

We conducted a similar test using GRID data and it yielded the following results:

Mosaic Test 2
Type of data: single band data
Input format: GRID
Number of files: 60
Average file size: 5.7 MB
Output format: GRID

Old Workflow – 45 minutes              
Create Raster Dataset time: 1 second
      Workspace to Raster Dataset time: 45 minutes

New workflow – 4 minutes
      Create Unmanaged Raster Catalog: 1 second
Raster to Geodatabase tool: 1 minute
Raster Catalog to Raster Dataset tool: 3 minutes

The new workflow is shown in model form in the following graphic: