The ArcPad Team Blog

Unofficial stuff from the team behind the World's leading mobile GIS platform

Wednesday, June 18, 2008

What is an ArcPad AXF?


ArcPad 7.1 has delivered a lot of new capabilities, many of which, such as the 'related tables', come from strengthened support of ArcGIS's Geodatabase capabilities in the mobile environment.

Prior to ArcPad 7.1, shapefiles were ArcPad’s most common spatial file format for features. Shapefiles are great for many applications, but shapefiles lack the capabilities to support more sophisticated relational database requirments that exist in the ArcGIS Geodatabase. So ArcPad 7.1 introduced the AXF format, which we like to refer to as a "lightweight geodatabase".

Not a new File Format

Now before you groan "Oh no not another spatial file format", like the ArcGIS Geodatabase, AXF is not actually a new file format but rather it is built on top of existing proven database technology. In this case, AXF is built on top of Microsoft's SQL Server Compact Edition (SQLCE).

SQLCE has been evolving for several years and has strengthened to become a powerful and robust database technology. Although in many ways it is the very little brother to the full Microsoft SQL Server, it has the distinction of being multi platform, being available for Windows CE and Windows Mobile operating systems as well as Windows and Windows Vista for the desktop. This includes the SQLCE database files themselves also being fully portable. You can create them on one platform and use them on another, exactly the sort of capability the multiplatform ArcPad system needs in a file format.

So how do AXF files work?

In the most simplistic terms, you might consider an AXF as a collection of shapefiles in a database. Where attributes in a shapefile are stored in a DBF, the equivalent attributes in AXF are just columns in tables. The ‘shape’ for each feature is stored in special spatial BLOB column, the contents of which are exactly as you would find in a shapefile’s .SHP file. The AXF schema, which describes to ArcPad how spatial data in the AXF database is organised, also stores metadata associated with each layer, including the projection details and layer definition containing symbology, forms and scripts.

A cool thing to note at this point, that where a customised collection of shapefiles might end as quite a few files, a collection of layers in an AXF remains a single file. This makes it much easier to move data around without the worry that one of the shapefile components gets lost which is of particular benefit in mobile environments where field users are sending back data files via email and only have to worry about a single file.

Integration with the ArcGIS Geodatabase

The power of the AXF “lightweight geodatabase really kicks in when you start to exploit the features of the ArcGIS Geodatabase in your organisation, in particular domains, sub types and relationships.

The ArcPad Data Manager and ArcPad Geoprocessing tools, automatically translate ArcGIS’s Geodatabase rules into AXF. This can result in significant benefits as you can design your rules in the Geodatabase and “just have them work” in the field with ArcPad, with almost no special customisation required.

If you want to customise your AXF further with forms and scripts, you can do so with ArcPad Studio in almost the same way as you can do it for shapefiles. You can create forms and scripts, all of which get ‘imbedded’ in the AXF along with the spatial data.

Workflow Benefits

The tight coupling of the AXF “lightweight geodatabase” with the ArcGIS Geodatabase has been designed to improve the whole enterprise --> field --> enterprise workflow cycle.

As your organisation builds rules in the enterprise geodatabase, these rules automatically become part of the field workflow with ArcPad, leading to higher quality data capture and maintenance in the field. Domains and subtypes automatically become ‘drop down’ menus for efficient and less error prone data input. This then in turn leads to less data maintenance effort when checking field data back into the enterprise geodatabase.

Further reading and information

This has only been a brief description of the AXF.

At the DevSummit this year in Palm Springs, we covered some more detail and you can see/listen to this online. http://edn.esri.com/index.cfm?fa=media.detail&media=122

There is a recent podcast covering a little on AXF.

At the forthcoming User Conference in San Diego, we will be presenting information in many more scenario contexts ranging from the more simple benefits, ArcGIS Geodatabase integration, workflow improvements and leveraging more through further customisation and the power of the SQLCE engine.

We will also expand on how ArcPad is going forward with AXF and integrating ArcPad field workflows directly with ArcGIS Server.






Labels: , , , ,

11 Comments:

  • At Thursday, June 19, 2008 7:43:00 am, Anonymous Nico Tripcevich said…

    Thanks for this useful write up.
    One concern I have about AXF is: what programs aside from Arcpad and Arcpad Toolbar (in Arcmap) can read AXF? Arcpad studio can do a "Data dump" from AXF but if there are corruption problems and Arcpad can't read the file do we have other options? The good thing about Shapefile is that there are a lot of other programs that could read it if Arcpad refused. You could even read the DBF attribute table in Excel Mobile. Not so with AXF.
    Since AXF is a form of SQL Server Compact maybe some MS apps can read AXF? Thanks

     
  • At Thursday, June 19, 2008 3:41:00 pm, Anonymous Lance said…

    Nico, you can open it up in SQL Server Management Studio like any other MS SQL Server database.

     
  • At Thursday, June 19, 2008 6:12:00 pm, Blogger Archaeogeek said…

    But if you're out in the field you're not likely to have access to SQL Server Management Studio. Many people won't even own any SQL server programmes...

     
  • At Friday, June 20, 2008 8:43:00 am, Blogger Marika said…

    IF you REALLY need to study an AXF in the field (and you cant open it in ArcPad) you can open it with SQL CE's Query Analyzer application which is installed with SQL CE on mobile devices (just change the extension to .sdf). With a development community the size of SQL Server available, the number of tools to open AXF's will only increase. In the meantime, SQL Server Express Edition (for desktop) is free - you can use this to open and edit AXF's if you need to.

     
  • At Friday, August 08, 2008 1:50:00 am, Anonymous Stephen March said…

    I actually have a fun issue with an AXF file where ArcMap crashes consistently when it's trying to process the changes from an AXF file. There are features which no longer exist in the Geodatabase and the transaction is trying to delete them. The AXF file does contain some new data from the field that I want to keep so I opened up the AXF file with ArcPad Studio to see if I could recreate the records manually (hey all the geometry is there obviously). So far I haven't been able to create these new features, but I do at least have them extracted. Anybody come across this before?

     
  • At Saturday, November 08, 2008 8:42:00 am, Blogger David said…

    How do I used MS SQL Server Management Studio Express to open an axf?

     
  • At Wednesday, November 19, 2008 4:30:00 pm, Blogger Marika said…

    choose 'connect to server' (this is usually the opening dialog of SQL Server Management studio) and ensure that you are opening a server type of 'SQL Server Compact Edition'(this is the first dropdown box on the dialog). then, in the database file dropdown, browse to your axf file.

     
  • At Thursday, February 12, 2009 11:59:00 am, Anonymous Daniel said…

    Thanks, your blogs have been very useful thus far. I have a couple of questions though...

    Does anyone know what versions of SQL CE are compatible with ArcPad 7.1.1? Would i be correct in assuming that the only limitation is on the mobiles devices' CE runtime itself?

    Also as the Data manager check out feature does not export GDB relationships, i'd like to programmatic ally recreate the relationships, has anyone tried this? I'm struggling to find documentation on how this can be done.

     
  • At Thursday, February 12, 2009 12:12:00 pm, Blogger Marika said…

    SQLCE 3.0 is supported in ArcPad 7.1.1 (and soon to be released 8.0). Also, the Data Mangager DOES check out GDB relationships.

     
  • At Tuesday, July 12, 2011 7:13:00 am, Blogger jdewalt said…

    Is there anyway to upgrade the axf file to a SQL Server Compact 3.5 format. I need to be able to connect to and modify the data from within a vb.net desktop program and can't seem to do it in its current format; visual studio says the databaase is an old format and must be updgaded. The only upgrade method I have found so far must be executed on a mobile device and that is not an option for me.

     
  • At Tuesday, July 12, 2011 8:25:00 am, Blogger Stephen Quan said…

    Hi jdewalt, SQL Server Compact 3.0 & 3.1 formats are chosen for ArcPad AXF since many Windows Mobile devices (5.0, 6.0, 6.1, 6.5) have the SQL Server engine in flash rom.

    Visual Studio 2005 has out of the box functionality for this version of SQL Server CE. Whereas, for Visual Studio 2008 and Visual Studio 2010 you will need to refer to the correct SQL CE assembly (System.Data.SqlServerCe.dll) in C:\Program Files\Microsoft SQL Server Compact Edition\v3.1 folder.

    For the connectionstring, look in the Book Online here: http://msdn2.microsoft.com/en-us/library/system.data.sqlserverce.sqlceconnection.connectionstring.aspx

     

Post a Comment

<< Home