The ArcPad Team Blog

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

Thursday, June 21, 2012

Feature Associated Photographs in ArcPad

We have discussed the ArcPad Photo Layer and including stand-alone photographs in your data collection in a previous blog – now let’s take a closer look at including feature-associated photographs in ArcPad.

 There are many ways to include a photographic record of your assets as part of your data collection project. You can include a 'Photo Field' in your data that will contain the file name of the photograph associated to that particular record. You can also include a related table to contain the file names of multiple photographs associated to a single record. This blog will describe the workflows used to take the Photo Fields from your data into the field using an AXF file and to then incorporate these photographs from the field back into your project. This involves using the ArcPad Data Manager Toolbar in ArcGIS Desktop.

Incorporating Photographs into your ArcGIS for Desktop Workflow
When you define photo options in the any of three wizards (Get Data for ArcPad, Configure Project for Geoprocessing, or Author Project for ArcGIS Server), you will minimize the number of steps required to ensure that photos taken in the field, return to the desired location on your network.

The following diagram demonstrates where photographs are located during a typical workflow and how they are moved.

In order to use this recommended workflow for incorporating photos into your project, you must start by ensuring you have fields in your geodatabase to store a text string that will represent the photo path, and a location (local or network) where you intend to store and use your photos from. When photos are returned from the field you will then be able to use ArcGIS Desktop hyperlink tools to view your photos.

Stage 1 of the diagram above, represents the completion of one of the 'check-out' wizards. When you complete the wizard, the resultant AXF will know which fields can accept photographs and will contain the Photo Path, ready for use at check in time.
In each of the three wizards:
- Get Data for ArcPad
- Configure Project for Geoprocessing
- Author Project for Server will have the opportunity to nominate:
- Photo Field(s) for each feature layer
- a folder for pictures to be copied to during Check-In

If you define Photo Field(s) for a layer, only those fields will appear in the Fields drop-down on the Picture Page of the Feature Properties dialog in ArcPad. This can be useful to ensure your users only add photographs to the fields you nominate. Take care to ensure your field length is long enough to store the file name and full path.

If you define a folder for pictures to be copied to at check in, two key actions will occur at check in:
- Photographs will automatically be copied to that location
- Photo Path will automatically be pre-pended with the defined location.

NOTE: If you already have photos associated to features in your layer, a copy of these will NOT automatically be added to the check-out folder. If you wish to take them into the field, you can copy them manually to your check-out folder.

In the Field
In the field you can use either an integrated camera or separate camera to the data collection device to capture photographs associated to features. For ArcPad to be able to display the photographs in the field, they must be located in the same folder (on the same device) as the AXF. If a separate camera is used, you will need to copy them to the AXF location. Some examples of how to get photos in the same folder are:
- Use a Memory Card to copy photographs between devices
- Use a WiFi or Bluetooth connection to automatically send files between devices

The Picture Page
You can collect a photograph associated to a new or existing feature in your data using the Picture Page on the Feature Properties Dialog. If you are using a custom form, your Feature Properties dialog box may not show the Picture Page. Custom input forms can optionally hide the default pages of the Feature Properties dialog box, including the Picture page. You can add the Picture Page to your forms using ArcPad Studio.

The Picture Page is used to display the photo, or digital image file, that is associated with the selected feature. The file name of the digital image is stored in a field associated with the selected feature. A feature can have multiple photos associated with it, but each photo file name needs to be stored in a unique field.

The bulk of the page is dedicated to the preview of the photo, which is referenced by the file name stored in the field selected in the Field drop-down list. The preview is a display-only field.

Choose the field in which to store the file name of the photograph associated with the selected feature using the Field drop-down list. ArcPad automatically populates the Field drop-down list with field names that appear to be suitable for storing photo file names if a photo field(s) is/are not specified during check-out. To do this, ArcPad looks for any text field - in the Shapefile data table or in the ArcPad AXF file - that has a name containing the words photo, image, or picture. The text field also must to have a minimum length of 20 characters.

Tap the Rotate Icons to rotate the image 90 degrees to the left or right. The rotated image is stored in the image file. Processing image files requires considerable free memory to perform the computations. You need to ensure that there is sufficient free memory on your device for ArcPad to perform the image rotation. 

Tap the Camera Icon to open the Camera tool to capture a new photograph, using the camera specified on the Camera Tab of the ArcPad Options dialog box. The new photograph will be stored on your device and displayed in the Picture Field. The image file name for the new photograph will be stored in the field selected in the Field drop-down list. 

Tap the Folder Icon to navigate to and select an existing photo on your device to be associated with your feature.

The associated photo can be changed by either using the camera button to open the Camera Tool for capturing a new photo or by using the Folder Icon to choose an existing photo on your device.
Returning Data and Photographs to your Desktop or Network
To check-in field data, you must still first copy the data (AXF and photographs) to a temporary location on your desktop or network. If you have been capturing photos on a separate device, and only entering the file name into the feature attribute in ArcPad, you can copy the photos from your camera directly to the temporary folder (In the diagram, this workflow is represented by the dotted line).

The Get Data for ArcPad wizard will automatically copy any photos found in the temporary ArcPad project folder, to the folder nominated during check in. If no folder was nominated, no photos will be copied.

I hope you are encouraged to incorporate photographs into your ArcPad Projects. Photographs can be a very useful tool in field data capture and photo support is a key feature in out-of-the-box ArcPad.