High Resolution Offline Maps

07-29-2021 03:29 PM
Occasional Contributor II


This is a never ending barrage of questions from me about a project that I have been working on for a while, but it has been great to get some advice from others about possible solutions based on their own projects.

Originally, when developing the project, everyone agreed that a somewhat low resolution satellite image would be great for an offline map. This would keep the file size down and not dissuade the public from using the survey.

Now, we have a volunteer coordinator that needs to go out in the field and know where he is with a detailed offline topographic map that contains the sites that were collected by the public. He needs to be able to see highway names, water body names, etc...

This introduces a couple of logistical challenges for the project. First, the offline map will have to be regularly updated with new data, which will probably be a pain. Second, if we push out a high-res offline map to the survey, it will increase the file size of the survey on the public's phones.

I have not really figured out an efficient way to constantly update the offline map with new data. However, I was thinking that maybe the coordinator could use Field Maps and have a more detailed high-res offline map that would contain the data collected from Survey123.

Does anyone have any experience with using a high-resolution offline topographic map so that people can navigate in the field?

Thanks and have a great afternoon.

3 Replies
Occasional Contributor II

I created a raster tile package file from a high resolution ortho imagery (10 GB) but both survey123 Connect and Field applications crash (with low memory error).  

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Occasional Contributor III

I've successfully loaded a 13.6 GB TPK for use with Survey123 on a 64GB  iPhone 8 and SE2. It was a beautiful high-res Nearmap image overlaid with CAD data.  It looked and worked great.

To circumvent the 2GB limit I used the OneDrive sideloading technique.  This would not be convenient though for the regular update of the basemap by a casual user;  it works, but it is far from a simple transparent process for the non-technical.

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MVP Esteemed Contributor

I would probably just use Field Maps for this.  It is much better at mapping and going offline.  You can just add the 123 feature service to a map and go.

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