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Design your layer

Collector allows you to create an asset inventory, record observations, and perform inspections in the field. Your mobile workers use the app in the field, collecting locations and filling out forms. The information mobile workers can provide is determined by the map they work with, and you define the map. You can include new layers as well as existing layers. The layers determine the information that can be captured in the form, and through the map you can customize the form for your mobile workers.

Before you make your map, you need to make some choices about the layers you'll use in Collector for your collection project.

  1. What spatial information do you need to capture? Single places, lengths, or areas?
  2. How should you store your layer for your project? The recommendations depend on the purpose of your collection and whether you require quality assurance (QA) or quality checks (QC).

    Purpose of collectionMobile worker task

    Create an asset inventory or record new observations

    Capture a new type of asset or observation, including location and form

    Add additional assets or observations to an existing collection

    Capture additional assets or observations (including location and form), supplementing an existing asset inventory or set of observations

    Ground truth existing assets and observations, correcting them when discrepancies are found

    Inspect existing assets or observations, updating location and form as needed when they don't match what is seen in the field

    Update existing assets or observations with current status, without a need for historical reports

    Update the form based on an inspection

    Update existing assets or observations with current status, keeping historical reports available

    Add a new related form to report on an inspection

  3. What should you include in the form? The form determines the types of information your mobile workers can capture.

Choose your spatial information

Before creating layers, think about the spatial information important to the work your mobile workers are doing. You'll need to create a layer that supports the appropriate type.

Capturing information aboutSpatial type to useExample

A single place on the earth

Points

A fire hydrant

A distance, or length, that you want to capture and measure

Lines

A road

An area, or space, that you want to capture and measure

Polygons

A building parcel

Choose how to store your layer

The layer storage recommendations depend on the purpose of your collection and whether you require quality assurance (QA) or quality checks (QC). See the recommendations based on the purpose of your collection:

It is recommended that if you're creating a new layer you create a hosted feature layer; however, you might need to use ArcGIS Server for your editable layer. If so, review recommendations for using ArcGIS Server for a new editable layer.

Create an asset inventory or record new observations

Your mobile workers capture a new type of asset or observation, including location and form. To support these projects, it is recommended that you create an editable hosted feature layer to hold the new type of assets and observations. Once the project is complete, review the new assets and observations. They then either become your authoritative layer or can be imported into ArcGIS Server.

Tip:

If you plan to maintain the assets and observations through inspections using the hosted feature layer created for this project, think about whether you'll want historical inspection reports or only current status. If historical reports are important, create the layer with related tables that you'll use later to collect the inspection information. This associates multiple forms with a single location. If instead only current status is important, you'll want to reevaluate the editing permissions on the layer once it is used for inspections, as the mobile workers won't need to update the location of assets and observations. When you are ready to use it for inspections, it is recommended that you restrict mobile workers to attribute updates, preventing them from accidentally changing the already-known locations.

It is recommended that if you're creating a new layer you create a hosted feature layer; however, you might need to use ArcGIS Server for your editable layer. This is supported (although creating such services is not covered in depth in this help). See Use ArcGIS Server for a new editable layer.

Add to an existing collection

Your mobile workers capture additional assets or observations (including location and form), supplementing an existing asset inventory or set of observations. Since QA and QC are often key to these projects, the recommended workflows are those that support QA and QC:

  • Create an editable hosted feature layer to hold the newly added assets and observations during the collection project. Once the project is complete, review the additions and import into your authoritative (existing) layer (either another hosted feature layer, or on ArcGIS Server).
  • Add the new assets and observations to existing versioned data in an ArcGIS Server feature service. Using versioned data provides a QA/QC workflow through reconciling and posting.
  • Add the new assets and observations to an existing layer and flag them for review. Include a hidden field indicating if the asset or observation has been reviewed, using a default value like new or not reviewed. Its value would be updated during QA/QC (for example, to reviewed). A new asset or observation can be part of your authoritative layer as it is collected, but the flag entry indicates to users if it is under review. You can even use a hosted feature view, choosing if your authoritative layer shows the in-progress, under-review assets or observations, or if they are excluded.

If using an existing layer, it must meet the editable data requirements.

Ground truth existing assets and observations

Your mobile workers inspect existing assets or observations, updating location and form as needed when they don't match what is seen in the field. The project layer recommendation is based on how your existing layer is stored and if QA and QC are required. There are recommendations for the following existing layers:

If using an existing layer or service, see Editable layer requirements.

Existing editable hosted feature layer

If you have an existing editable hosted feature layer, and don't require QA/QC, use the existing layer. If your project requires QA/QC, there are two recommended structures for your project layer. Choose the one that best fits your organization's workflows:

  • Create an editable hosted feature layer for the project and import your existing layer into it. Either include a flag indicating changes or use editor tracking to know what has changed over the course of the project. Once the project is complete, review the changes and append to your authoritative (existing) layer.
  • Add an entry to the form of the existing hosted feature layer to flag edited assets and observations for review. Use the existing hosted feature layer for the project and review flagged assets and observations.

Existing versioned data in an ArcGIS Server feature service

If you have existing versioned data in an ArcGIS Server feature service, use your existing service in Collector. Since your layer is versioned, you'll do quality assurance checks before the edits are brought into the version representing the current state of the system (versioned data provides a workflow through reconciling and posting).

Existing archive-enabled, nonversioned data in an editable ArcGIS Server feature service

If you have archive-enabled, nonversioned data in an editable ArcGIS Server feature service, and don't require QA/QC, use the existing layer. If your project requires QA/QC, there are three recommended structures for your project layer. Choose the one that best fits your organization's workflows:

  • Create an editable hosted feature layer for the project and import your existing layer into it. Either include a flag indicating changes or use editor tracking to know what has changed over the course of the project. Once the project is complete, review the changes and append to your authoritative (existing) layer.
  • Add an entry to the form of the existing layer to flag edited assets and observations for review. Use the existing layer for the project and review flagged assets and observations.
  • Version the data and publish an ArcGIS Server feature service to use for the project. Use reconciling and posting to review the changes, bring them into the versioned data, and then import to your original, nonversioned data.

Existing layer not supported for editing in Collector

If you have an existing layer not supported for editing in Collector, and don't require QA/QC, create an editable hosted feature layer for the project and import your existing layer into it. If your project requires QA/QC, there are two recommended structures for your project layer. Choose the one that best fits your organization's workflows:

  • Create an editable hosted feature layer for the project and import your existing layer into it. Either include a flag indicating changes or use editor tracking to know what has changed over the course of the project. Once the project is complete, review the changes.
  • Create versioned data in an ArcGIS Server feature service for the project and import your existing layer into it. Once the project is complete, use reconciling and posting to review the changes and bring them into the versioned data.

The new layer then becomes your authoritative layer and is imported into ArcGIS Server or exported to your previous format.

Record current status (no historical records)

Your mobile workers update the form based on an inspection. The project recommendation is based on how your existing layer is stored and matches the recommendations made above for ground truthing projects.

In addition to the ground truthing project recommendations, it is recommended that you restrict mobile workers to attribute updates, preventing them from accidentally changing the already-known locations. One way to do so is to create a hosted feature layer view that only allows attribute updates (see Limit the data available to mobile workers). One benefit of doing so is ensuring high-accuracy GPS positions are not updated, maintaining recorded metadata.

Record current status with historical records

Your mobile workers add new related forms to report on an inspection. When historical reports are important, use related tables to capture the inspections. This associates multiple forms with a single location. Like the mobile workers that record current status without historical records, these workers also won't update the location of the assets and observations.

The project recommendation is based on how your existing layer is stored and matches the recommendations made above for ground truthing projects. However, if your existing layer doesn't have related tables, it is recommended that you import your existing layer into a new layer that does. This layer can be a new hosted feature layer or an ArcGIS Server feature service.

Use ArcGIS Server for a new editable layer

It is recommended that if you're creating a new layer you create a hosted feature layer; however, you might need to use ArcGIS Server for your editable layer. While this is supported in Collector, the steps for creating such services are not covered in depth in this help. Based on the type of data collection project you are doing, some recommendations for your ArcGIS Server feature service are presented below.

If you are capturing assets or observations (including creating an asset inventory, recording new observations, and adding additional assets or observations to an existing collection) using ArcGIS Server, a good choice is to use archive-enabled, nonversioned data in a feature service. Since the mobile workers aren't editing the same assets or observations, you don't need versioned data to manage conflict resolution. Another benefit of versioned data is the ability to do quality control before the data is brought into the version representing the current state of the system; however, capture of new data should be managed separately and done outside your authoritative data. The data quality can be reviewed as part of the project, instead of as part of managing versioned data. Once reviewed, the data can be merged into the authoritative data. Going forward, you're likely to maintain this data through the authoritative data, and the originally captured data won't be used for maintenance. See the data requirements for ArcGIS Server feature services.

If you are ground truthing existing data or performing inspections using ArcGIS Server, a good choice is to use versioned data in a feature service. While mobile workers might not be inspecting the same assets or observations, it is common for them to be editing data that is already in a production database and used throughout your organization. You'll do quality assurance checks before the edits are brought into the version representing the current state of the system (versioned data provides a workflow through reconciling and posting).

Form design

Mobile workers rely on the form. As you prepare your layer, remember that the form entries are driven by the structure of your layer—the fields in your layer are the entries in the form your mobile workers use in Collector. If you're creating a layer, keep this in mind as you add fields to it. If you're using an existing layer, consider updating it to provide a better form.

Form entriesData to support it

Drop-down lists

Use a coded value domain to provide mobile workers with a list of valid choices. You can also use subtypes to constrain the choices based on choices made for other entries.

Numeric ranges

Prescribe the range of values that are valid by using a range domain.

Required information

Use required fields to force mobile workers to provide information in particular entries of the form.

Default values

Provided a default value that populates the entry in a new form.

Date selection

Use a date field type (not string) so that mobile workers are provided with a date-selection experience in the form.

Attach a photo, video, or audio clip

Enable attachments on your layer.

Information from scanning bar codes or QR codes

Collector allows text and string entries to be populated by scanning a bar code or QR code.

Record GPS metadata

Prepare your layer to record GPS metadata. (This is just one part of preparing for high-accuracy data collection.) This is supported for point layers.

Track edits

If you need to know who is collecting or modifying the data, enable editor tracking on your layer and Collector records it for you.

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