Offline Mobile Map Data Plotting App Help
What is the purpose of the Offline Maps App?
The App is designed for offline (no wifi) field data collection using smart phones and tablets with a level of accuracy that meets the needs of most student projects. Getting within 10 metres is usually more than adequate to map and plot a range of geographical data. Users can create data maps using geo-located map markers supporting colour shading, text, numerical (decimal) data and images. Editable worksheets supporting multiple data inputs for a location are provided in the App as an optional feature. Map images may be downloaded with geo-located markers showing data or text values. The maps can be inserted into a student investigation report without further work or further data analysis undertaken. Overlays can assembled using an image editor. Maps with plotted data can be saved and exported as an html page for desk top use or interactive presentation online. Images and worksheet multiple data are displayed when a marker is clicked in the App or in html page view.
How does the App work?
Your location is shown on the map by a small blue marker which follows your movement. Plotting a data marker drops it into the centre of the map to be dragged to your location. The accuracy of your location should be checked against features of the landscape that are visible on the map.
How accurate is the App?
Accuracy depends on a wide variety of factors coming together at a particular location and time. Smart phones and tablets use a hybrid locational system combining three separate technologies as available: Assisted GPS, WiFi positioning and Cellular network positioning. Assisted GPS is the most accurate of the three, and cellular positioning the least accurate. The best studies to date are those by Dr. Paul Zandbergen at the University of New Mexico (2009). His research showed that an iPhone 3 had an average accuracy to 8 metres with the error never exceeding 30 metres. [1]
How can I improve the accuracy?
Some devices, e.g. Samsung, have a Switching Mode to improve or change accuracy:
- High accuracy: this option has the highest level of accuracy, using GPS, Wi-Fi, and mobile data networks interchangeably to estimate your location. Data charges from your mobile network may apply when using this option.
- Power saving: this option uses only Wi-Fi and mobile data networks to estimate your location. Data charges from your mobile network may apply when using this option.
- GPS only: this option uses only the GPS network.
For the highest accuracy, use bluetooth to connect your device to a small portable GPS receiver. Available from about €100, the receiver will provide approximately 2.5 metre accuracy. [2]
Who should use the App?
Any researcher wishing to record geo-located data in the field as colour, text, numerical (decimal) and image.
Is it free?
It is free for students and staff who visit us in Barcelona.
How do I import a map to get started?
A map name is provided by us for you to download. If you encounter a 'map not found' error, please check you have entered the name correctly (case sensitive) and that your device has a wifi connection.
How can I request a particular map?
Maps can be requested from https://geographyfieldwork.com/RequestMap.htmHow can I open a map after importing it and how can I delete it?
A map can be opened in iOS by clicking on the map name. Deleting a map in iOS is done by swiping the row to the right of the map name. This reveals the 'trash' button. In Android, the black trash bin and red open map icons appear alongside the map name.
Why does the App ask me to allow GPS access?
Allowing GPS access improves the location accuracy of your data plotting to within 5 to 8 metres.
Do I need an internet connection to get my GPS location?
The App works offline without an internet connection. Enabling an internet connection may improve the accuracy of your geo-located data plotting. Using wifi alone without Assisted GPS or Cellular positioning will give a level of accuracy to approximately 74 metres. [3]
What are the default data categories and do I have to setup them every time I open a map?
When you import a map for the first time, you are asked to select and save the data category or categories you wish to geo-locate from a list of default options. You can create your own data categories if needed. Reopening the map will show your selected categories, skipping the default data categories option menu.
I want to add my own data category. How can I do this?
Click the 'Add New' button on the default data category menu.
I want to use the worksheets to collect multiple data at my sampling locations. How do I do this?
Click the 'Worksheet' category on the default data category menu. This will take you to Step 2 (insert data) where a link is provided to the worksheets page (Step 3). Enter data (colour, text, numerical) in the categories you wish to record data for. An option ('User Defined') allows you to setup your own worksheet if needed. Once you have applied the data, you can add an image by editing the marker. The Edit Marker menu which opens has a 'Data Selection' link at the top, which allows for an image to be added, amongst other options.
How do I save my data inputs on the map?
Click the 'Save Map Changes' option on the map menu.
How can I change the data value of a map marker?
Click the marker then click the edit button.
How can I remove a marker from a map?
Click the marker then click the delete button.
What are the differences between the export map options?
'Export as Data Markers Only (transparent map)' exports the markers in their plotted positions, but with a transparent background. This allows for the creation of overlays using your desktop image editor.
'Export as Image With Data Markers' exports the complete map and located map markers, with visible data values (if entered).
'Export as Image Without Data Markers' exports just the map to allow for the creation of marker overlays using your desktop image editor.
'Export as HTML' exports the files needed to display an interactive web page containing your complete data. Clicking on the markers on the web page displays all your recorded detail.
Where can I find the exported files?
Android: the location may vary according to your device. Huawei iPad exported files are saved to the Offline Maps folder located as follows: Files > Local > Internal Storage > Offline Maps. Html pages in Huawei are saved to the Files > Archives folder.
Apple: Exported files can be downloaded by from iTunes, with your iOS device connected.
How do I download the exported files?
Android: email the files to yourself as attachments or connect a USB cable to your device and copy the files into a USB flash drive (thumb drive, pen drive).
Apple: Connect your device to iTunes to locate and copy the files.
How do I locate my current position on the map?
Click the 'Go to my current location' on the map menu options.
How do I go to the centre of the map?
Click the 'Go to the centre of the map' on the map menu options.
How do I add a single value marker?
Select and save the data category you wish to geo-locate from a list of default options. You can create your own data category if needed. Click 'Add Marker' from the map menu, insert your data (optional), click 'Apply', which opens the Step 3 Worksheets (optional) menu, then click 'Skip' or 'Apply' to place the marker on the map.
I have a problem using the app.
Map help can be requested from https://geographyfieldwork.com/RequestMapAppHelp.htm.
The App places a location marker on a map away from my actual position. Is this expected behaviour and is there a way of preventing it?
Yes, this can happen. There may be occasions when GPS cannot be set, is inaccurate, turned off, or you have opened a map of a different area by mistake. You are advised to check the accuracy of the location markers you position with the help of the features you can observe in the field (street names, roads, buildings, landmarks etc.). Location markers can be dragged to any location and their position saved.
The text font colour on my device is very difficult to see on the App's black background.
Try turning off 'High Contrast Fonts' found on Samsung S7 at: Settings > Accessibility > Vision > High Contrast Fonts.
I am trying to download the App and get an error message: 'no apps can peform this function'.
On a Samsung device, go to Settings > Apps (or Application Manager) then select Offline Maps and enable it.
The map disappears when pressing the 'Go to current location' button.
This happens when your location is away from the map or there is a problem with your GPS signal. If you press 'Go to the centre of the map' the map should appear again.
I have a suggestion or enhancement idea.
We welcome Map App suggestions or enhancement ideas. These can be sent from https://geographyfieldwork.com/MapAppFeedback.htm.
[1] Zandbergen, Paul & Barbeau, Sean. (2011). Positional Accuracy of Assisted GPS Data from High-Sensitivity GPS-enabled Mobile Phones. Journal of Navigation. 64. 381 - 399. 10.1017/S0373463311000051.
[2] Michael G. Wing , 2011. Consumer-Grade GPS Receiver Measurement Accuracy in Varying Forest Conditions. Research Journal of Forestry, 5: 78-88.
[3] BYOD (Bring Your Own Device) Sub-Meter Positioning for Mapping and GIS Professionals - GPS World
Offline Mobile Map Data Plotting App
Offline Mobile Map Data Plotting App Screenshots