ArcGIS Collector

Speed up offline Collector deployments using sideloaded basemaps

Mobile data collection in a connected world is much simpler.  However, many users need to collect assets or perform inspections in areas where there is limited or no connectivity.  In this case, getting an offline map onto your mobile device can be a challenge, particularly if they need a detailed basemap covering a large geographic area.  In this blog we’ll cover a few strategies to configure your maps to reference basemaps on your device and show how you can deploy those basemaps to your devices running Collector.


The largest component of most offline maps is the basemap.  The size of the basemap can delay getting your mobile workforce to the field, especially where network connectivity is limited or inconsistent.

You can significantly reduce the size of the data you need to download for an offline area by deploying your basemap as a tile package ( .TPK, .TPKX, or .VTPK) to the device ahead of time.  There are three main steps to this approach:

  1. Configure your map to use a referenced basemap
  2. Copy a tile package (basemap) to the device
  3. Download the map area

Let’s walk through each of these steps in a bit more detail.

Step 1 – Configure your map to use a referenced basemap

As a map author or GIS administrator, you can determine which maps are designed to be used with a basemap already present on the device.

Access web map’s offline settings

Within the web map’s offline settings, select Advanced Options.


Web map offline settings

Specify file name of basemap

Indicate that the web map should use a tile package on the device as a basemap

Specify the name of the basemap you want this map to use when working offline.  Supported tile package formats include raster tile or vector tiles. (.TPK, .TPKX, or .VTPK).


Specify Basemap file name
Specify a tile package file name

Save your changes

We have configured the web map to use a tile package on the device when taking the map offline. The next step is to copy a basemap to the iOS device.

Step 2 – Copy a tile package (basemap) to the device

There are a few ways to do so that we’ll review next, including using iTunes, using the iOS Files app, or peer-to-peer sharing.

Sideload basemaps using iTunes

The iTunes desktop app has traditionally been the preferred method for getting a basemap to an iOS device for use in Collector. The steps are outlined in Collector’s documentation, and it is a reliable way to copy information to the device, even when you don’t have an internet or WiFi connection. However, this does have some drawbacks and limitations:

These limitations often result in a small number of laptops available to service a large number of mobile devices. Even when the laptop to device ratio is small, in many cases there aren’t enough field staff to support the process of sideloading through iTunes.  This results in a long line of mobile workers impatiently waiting to get their device updated so they could start work.

Share basemaps using the Files app

With the latest release of Collector for ArcGIS you now have another alternative to get your basemaps out to the device.  Using the Files app on your iOS device you can copy a basemap from cloud storage and make it available from Collector. In addition, this eliminates the need for iTunes.

This offers several advantages over the traditional iTunes method:

Copy basemap using Files app

Peer-to-Peer basemap sharing

One final approach is to reduce the number of independent downloads of the basemap. This is particularly important when you have multiple mobile workers in the same geographic area and connecting to the same Wifi network.  For example, a number of field staff are at the same location and need to use the same basemap. In this case, one person can download the basemap, then use technologies like AirDrop to share that basemap with others nearby.  This also has the advantage of minimizing cellular data usage if WiFi is not available.


Video using AirDrop to share basemap

AirDrop generally performs well, even for large files such as tile packages.

Step 3 – Download the map area

In Collector, download a map area for the map that uses the sideloaded basemap. You can download either a map area defined as part of the map or a map area defined in the app. The sideloaded basemap is used with both. Since the basemap is already on the device, only the operational layers are downloaded. This reduces the amount of time and bandwidth required. Once the map area is downloaded, you can use it as you would any other map.


Download offline area using basemap on device

Wrapping up

Using tile packages already on the device offers significant advantages in getting your staff out into the field with Collector quickly. Try some of these techniques in your next mobile data collection or inspection project, and increase productivity of your mobile workforce and reduce demand on your GIS staff.

Here are some resources from the Collector documentation that you may find useful:

About the author

Doug is the Product Owner for Collector for ArcGIS. He works to extend the reach of GIS to include the mobile workforce to help organizations make quicker, more informed decisions.


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