18 Replies Latest reply on Nov 16, 2012 12:48 PM by cndnflyr

    Geodatabase Design

    stephanieduce
      Hello,

      I have a lot of data including roads, drainage, contours, land use, habitat, shorelines, marine protected areas (.shp) as well as DEMs etc.... for a group of islands. I would like to organise this data into one, or more than one, geodatabase(s). I have not worked with geodatabases before (though have done quite a lot of work with GIS) and am not sure how best to approach this.

      - Would it be best to make my own data model or to add my data to an original data model such as ArcMarine etc...

      - Should I create separate geodatabases to house the terrestrial data and the marine data? If I do will it be fine to work with them both simultaneously in ArcMap? They are both the same coord system.

      - Would it be appropriate to divide each island's data (i.e. roads, infrastructure, buildings etc..) into a separate feature dataset within a geodatabase?

      Any help will be much appreciated.
      Thanks in advance,
      Steph
        • Re: Geodatabase Design
          Hardolph
          Stephanie,

          the simplest starting view on setting up your geodatabase is along the lines of how you would organise the data in normal computer folders.  

          Next what data do you want to be able to edit in the same session (all that should be in one gdb).  You can access as many geodatabases as you want in a project, but only edit from one at a time.

          Even if coordinate system are not an issue the feature datasets make handy folders for organizing feature classes.  If different projections are used or you might want to reproject a set of feature class then sort them that way into feature datasets.  You can reproject a whole set of FCs at one go by reprojecting the feature dataset.

          The next level of utility for the gdb is the use of domains for editing:  you can have any number of domains in one gdb and use them in all the FCs in that gdb.  So your different types of data terrestrial vs marine would use different domains, but they can all be available in the same gdb.

          Other behaviour that requires ArcEDITOR or ArcINFO is also housed in the gdb (representations, topology etc.).

          The only other considerations are size:  personal geodatabases have a limit of 2 Gb and only are mandatory if you require editing using Access. Otherwise just used File Geodatabases and stuff it full of all your data.  You can always make replicates.

          As for data models that may be getting down to the design of individual feature classes and how various fields interact using subtypes and domains.



          Hardolph
          • Re: Geodatabase Design
            dlaw-esristaff
            Hi Stephanie,

            This is a good place to start learning about some geodatabase design patterns and best practices:

            An overview of geodatabase design

            Hope this helps,
            • Re: Geodatabase Design
              stephanieduce
              Thank you very much for your useful tips Hardolph!
              Yes the Overview is also very helpful and well written thank you Derek.
              :)
              • Re: Geodatabase Design
                stephanieduce
                Just one more question...
                Hardolph you said that if I want to be able to edit using Microsoft Access I need to use a personal geodatabase. Does this mean that if I use a file geodatabase it can only be edited in ArcCatalogue?
                Thanks, Steph
                • Re: Geodatabase Design
                  dlaw-esristaff
                  Hi Stephanie,

                  Your statement is correct. A File geodatabase can only be edited using ArcGIS Desktop. An MS Access personal geodatabase (which is implemented on an MS Access file) can be edited using Microsoft Access - but is not officially recommended.

                  FYI: if you are going to start a new project, I recommend that you use a File geodatabase over an MS Access personal geodatabase. Please see this ArcUser article,

                  Top 9 Reasons to Use a File Geodatabase

                  Hope this helps,
                  • Re: Geodatabase Design
                    stephanieduce
                    Thanks Derek,
                    That is helpful. I think a file geodatabase is the right choice.
                    The only thing I'm worried about is that in the organisation I'm working for not many people use or have any knowledge of ArcGIS or GIS at all. I still want them to be able to at least know what data is available and potentially view the metadata.
                    Can you think of a way to do this? I was thinking perhaps a wiki but it would probably have to be separate from the geodatabase.
                    Your help and advice is greatly appreciated!
                    • Re: Geodatabase Design
                      dlaw-esristaff
                      Hi Stephanie,

                      One of these developer samples might address what you're looking for. They enable the creation of a visual "schema-diagram" of the contents of a geodatabase:

                      1. ArcGIS Diagrammer 9.2/9.3

                      2. Geodatabase Diagrammer for ArcGIS 9

                      3. Geodatabase Reporter.NET (9.2)

                      Hope this helps,
                      • Re: Geodatabase Design
                        drstrip
                        I'm struggling to get my arms about how a geodatabase is used. The example in the help shows a variety of feature classes relevant for mapping a town. These include wells, road centerlines, parcel boundaries, etc. So far, so good. If I'm mapping Smallville, I set up this geodatabase and populate the feature classes. Now I decide to map Gotham. I don't want to just add Gotham data to the Smallville data, do I? Does this mean I have to create another parallel geodatabase with the same structure, or can I somehow create "folders" within the same geodatabase, one to contain Smallville data, and another for Gotham?
                        • Re: Geodatabase Design
                          dlaw-esristaff
                          Hi David,

                          Does this mean I have to create another parallel geodatabase with the same structure, or can I somehow create "folders" within the same geodatabase, one to contain Smallville data, and another for Gotham?


                          Actually, you can do either option. It really depends on the requirements of your business workflow(s) and what you want to do.

                          Option 1: Have 2 separate geodatabases, one for each city. This enables each city to have and be able to maintain their own geodatabase, independent of each other.

                          Option 2: Have a single geodatabase, with 2 feature datasets (these are conceptually similar to "folders" - but contain data that are spatially related), one for each city. In this case, all GIS data is stored in one location, but the cities share ownership and access to the geodatabase.

                          This book is a good resource for learning about geodatabase design: Modeling Our World 2nd Edition by ESRI Press.

                          Hope this helps,
                          • Re: Geodatabase Design
                            ekulrenlig
                            I am also in the beginning stages of database design.  I was originally planning on going with the file geodatabase, but I would like the ability to use Excel and Access for editing, querying, reports, forms, etc. so decided to go with the personal geodatabase.  Is this an acceptable approach?
                            • Re: Geodatabase Design
                              dlaw-esristaff
                              Hi there,

                              ... but I would like the ability to use Excel and Access for editing, querying, reports, forms, etc. so decided to go with the personal geodatabase. Is this an acceptable approach?


                              You should use the type of geodatabase that best meets the needs of your business workflow, so using a MS Access personal geodatabase is fine. However, please be advised that directly editing a personal geodatabase with MS Access is not recommended.

                              Understanding how to use Microsoft Access files in ArcGIS

                              Hope this helps,
                              • Re: Geodatabase Design
                                HealdsburgCA
                                I appreciate finding an entry level discussion of geodatabases.  I have a ESRI book "Designing Geodatabases" from 2004 which I am reading and I am looking into purchasing the book Derek suggested. 

                                While our City has been using ArcGIS for the past 10 years, due to constraints with the 3rd party web interface we've been using we have not ventured into geodatabases.  We are now working to take our GIS to the next level �?? we recently began using ESRI�??s Small Goverment Enterprise package & will be moving to ArcSDE & SQL this coming summer.

                                I apologize in advance for the long list of questions below but I�??ve been chewing on a bunch of questions and it would be great if someone could help me gain some clarity:


                                1) We are in the conceptual stage of building file geodatabases.  With moving to SDE & SQL on the horizon, what considerations should I be taking in constructing my geodatabases?  Do I run the risk of having to redesign my entire geodatabase from scratch once we move to SQL?

                                2) I am trying to wrap my mind around the various constraints in geodatabase structure design. 

                                If I understand Topology Rules correctly, topology relationships can only be created/maintained between feature classes within the same dataset.  Originally our plan was to maintain our current folder structure by creating Geodatabases for different department uses (Public Works, Planning, Fire, general shared planimetrics, Parks, etc.)  Learning about how relationships work via datasets we considered a larger geodatabase with each department in their own dataset.  However from what I'm reading this is a bad idea though I don't know why.... I am assuming I am not grasping some of the concepts which make up a dataset.

                                Reviewing ESRI's design models <http://resources.arcgis.com/content/water-wastewater-and-stormwater-data-models%20> I am not clear on why each utility is broken out into its own dataset, I suppose there are limits on how many topology rules/geometric networks a dataset can handle? (Perhaps I'm simply stuck on editing in our current file structure where I edit the Public Works folder and I am able to edit all of the utility data vs each utility broken out into its own data set to be edited individually).

                                A similar issue is that we would like for changes to the parcel layer (in the general shared dataset) to directly relate to the zoning features (planning dataset) and water zones features (public works dataset) etc.  Can relationships and topology be built between datasets? 

                                Can a dataset have both topology & geometric networks?

                                3) Are there limits to how many feature classes can be in a given dataset?

                                4) We are designing a global ID system for all of our utility assets and dynamic values are a new territory for us, could someone point me in the right direction for creating GUID dynamic values?  If all of the features are within the same feature dataset our GUID�??s can be designed to be unique between each of the different feature classes right?  When I right click a feature dataset in ArcCatalog I have the option of "Add Global IDs..." after doing this I check out the properties of the features within that dataset and under the Fields tab it shows a new field "GlobalID", however when I add these features to a map I don't see this field, Am I missing something? 

                                5) The Geodatabase Diagrammer links posted above are for past versions of ArcGIS, is this ability still available for Arc 10?  Now that I've moved to Arc 10 I'm having trouble finding Scripts for the new version, is there a guide to what 9.3 scripts from the ESRI website carry over into Arc 10 or do none of them work? 


                                Again I apologize for dumping all of these questions but the Help Docs & Forums are anything but exhaustive. 

                                Any assistance is appreciated.
                                • Re: Geodatabase Design
                                  dlaw-esristaff
                                  Hi Joshua,

                                  1) We are in the conceptual stage of building file geodatabases.  With moving to SDE & SQL on the horizon, what considerations should I be taking in constructing my geodatabases?


                                  A1) Please listen to the Esri Instructional podcast titled: "Migrating from Single-user Geodatabases to Multiuser Geodatabases". A transcript is also available.

                                  Esri Instructional podcasts
                                  (look under the Geodatabase filter)

                                  Do I run the risk of having to redesign my entire geodatabase from scratch once we move to SQL?


                                  A2) Geodatabase schema design is transferable between different types of geodatabases. So you could define your GDB schema in a File geodatabase, then migrate it to an ArcSDE geodatabase. But there many be some additional considerations when migrating to an ArcSDE geodatabase - please refer to the podcast.

                                  Can relationships and topology be built between datasets?


                                  A3) I believe relationship classes can exist across feature datasets. Topologies only exist within the same feature dataset.

                                  Can a dataset have both topology & geometric networks?


                                  A4) Yes, a geometric network and a topology can both exist within the same feature dataset. However, feature classes in the feature dataset can only participate in either the geometric network or the topology. They cannot participate in both data structures.

                                  Are there limits to how many feature classes can be in a given dataset?


                                  A5) I'm not aware of any known limits.

                                  The Geodatabase Diagrammer links posted above are for past versions of ArcGIS, is this ability still available for Arc 10? 


                                  A6) FYI, the Geodatabase Diagrammer has always been an unsupported Developer sample for ArcGIS. I don't believe the developer who wrote it has migrated it for ArcGIS 10.

                                  Hope this helps,
                                  • Re: Geodatabase Design
                                    dcfrate
                                    We're about to move to ArcGIS 10, and I've been looking into whether there are new options for geodatabase design in the new version.  However, most of what I'm reading online seems to suggest that, although designing with UML is still supported, ESRI now recommends doing everything within ArcCatalog.
                                    But I see nothing so far suggesting that ESRI has improved this experience.  Is there a way in Catalog now to create the database as a diagram (a la Visio)?  Or does is it still the tedious process that it has been in the past, with no way to review the entire database on screen as I make changes?

                                    Thanks.
                                    • Re: Geodatabase Design
                                      dlaw-esristaff
                                      Hi Carlo,

                                      Is there a way in Catalog now to create the database as a diagram (a la Visio)?


                                      No, this functionality is not available in ArcCatalog. I suggest you vote for this functionality on Ideas.arcgis.com:

                                      Idea: Add a utility or tool to create, edit and analyze the geodatabase schema

                                      Hope this helps,
                                      • Re: Geodatabase Design
                                        dcfrate
                                        Hi Carlo,



                                        No, this functionality is not available in ArcCatalog. I suggest you vote for this functionality on Ideas.arcgis.com:

                                        Idea: Add a utility or tool to create, edit and analyze the geodatabase schema

                                        Hope this helps,


                                        Will do.  Thanks.
                                        So, although ESRI's official suggestion is to move away from working in UML, there is no better alternative available?
                                        • Re: Geodatabase Design
                                          dananrg
                                          One possibility is Enterprise Architect's new ArcGIS UML profile:

                                          I blogged about it here:
                                          http://spatialdba.com
                                          http://spatialdba.com/?p=50

                                          If you follow the links through to Sparx Systems' web site, you'll find a video demo:
                                          http://www.sparxsystems.com/resources/demos/arcgis/arcgis-ea-intro.htm
                                          • Re: Geodatabase Design
                                            cndnflyr
                                            If anyone finds this thread, just wanted to let them know that the Geodatabase Diagrammer for ArcGIS 10 can be found here:

                                            http://resources.arcgis.com/gallery/file/arcobjects-net-api/details?entryID=F12ADF8F-1422-2418-34B2-C276C6BCCF98

                                            or a slightly different implementation here (haven't tried this one):

                                            http://www.arcgis.com/home/item.html?id=a378b48be11b45b5bb25254643304cb7