Line Streaming in QuickCapture

[ChauhanYashwant]

Hello

Is it possible to change streaming interval for line and polygon features in QuickCapture?

[IsmaelChivite · Accepted solution]

Yes. You can change the distanceThreshold property in the project through the JSON editor as shown below. The distanceThreshold is defined as the minimum distance that must exist between two consecutive vertices in a polyline or polygon. It is always expressed in meters. You can use an integer or decimal value. If you use a decimal value, enter a . as a decimal separator.  Do NOT use a comma as the decimal separator.

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[ChauhanYashwant]

I see there is time threshold too. Can this be customized to log a vertex every second?

Thanks

[JohnathanHasthorpe]

Hi Chauhan 

The time threshold is currently an unsupported property. As a result, you will get a new vertex at the default frequency of your location provider, which will be at least 1 vertex per second (1Hz). An external GNSS sensor could provide more than one vertex per second if operating at a higher frequency (>1Hz).

Thanks

John

[kmsmikrud]

Hi,

I have a similar question to the one posted in changing the streaming distance threshold. Currently we have a project that has a point layer we would like to use the streaming points as our survey tracks to be able to get the GPS metadata. The aerial surveys we are using the Quick capture project for are offline and I'm wondering if you have a distance threshold you would recommend for this application. I'm also wondering if there is a limit to the number of streaming points that can be stored on the device offline. When I briefly used the button to collect streaming points in town it looked to collect 25-30 points and then send them? I'm not entirely sure, but don't want to hit some upper limit for storing data offline.

Thank-you!,

Kathy

[JohnathanHasthorpe]

Hi Kathy,

By default, the distanceThreshold for a project is set to 5m. Meaning that for every 5m of travel, the app will capture a new vertex or streaming point. You could increase this number (in the project JSON) to 10 in order to half the number of points captured, but this would reduce their density.

Note that DistanceThreshold is a project setting so it will affect all buttons (layers) in the project. This does not matter for single point buttons, as the app always takes the location when the button is pressed. But if you were capturing lines or polygons, these would not be as detailed.

In terms of sending data, the app allows you to specify the frequency this happens at. By default, the app will auto send all data on the device every 30 seconds. You can disable autosend (the user will then need to manually upload the points when ready), or make the autosend less frequent.

In terms of storage, features take a tiny amount of storage in online - I really would not worry too much about this (especially as these features do not have attachments). Take a look at the following: Understand credits—ArcGIS Online Help | Documentation for more info. 

I hope this all helps, please let me know if you need any further info.

Thanks

John

[kmsmikrud]

Thank-you John. The information you provided is very useful. I still do have a remaining question, the surveyor will be working offline so the user will be manually uploading the points after their survey when they are back to a connection. 

My question, for streaming points is there a maximum capacity that a user could reach when using Quick Capture offline. The surveyor could potentially be streaming points for up to 8 hours a day depending on when they choose to use that feature. I just didn't know if the offline capacity reached some maximum and we would lose data? Hopefully my question makes sense.

Thanks again,
Kathy

[JohnathanHasthorpe]

Hi Kathy

8 hours' worth of points could take a bit of time to upload, but uploads are done in batches of 100 so this should help. There is no limit for the number of features that can be stored in the app, and breadcrumbs are very small for a storage perspective so it is highly unlikely that you would fill up your device. If any records fail to upload for any reason (e.g. poor connectivity) the app will show the user an error and allow them to try again, or send the data as an email. 

The app should be able to support your workflow without any issues, you should not be concerned with the number of points being captured while offline.

Thanks

John

[kmsmikrud]

Thanks John. We'll change the interval for recording points. Thanks so much for all the great info. It makes me feel better. Thanks, Kathy