Android Applications forGNSS(SW Maps and RtkDroid)

Avinab Malla
avinabmalla@yahoo.com

SW Maps• Free Android Application for collecting,presenting and sharing geographic
information• Can be used for large scale GNSS
surveys to collect detailed attributeinformation or just to display popular
GIS data formats on Android• Downloaded more than 100,000 times
by users all over the world

Features• Collect data using internal and external GNSS receivers (Bluetooth or USB). Connect RTK
capable receivers for high accuracy surveying.
• Import and display popular GIS Data formats (KML, Shapefiles, GeoJSON, MbTiles)• Google Maps or OpenStreetMap as background; Can also import and cache maps fromonline sources (WMS, XYZ Tiles)• Record tracks and photos.
• Export or share collected data directly to KMZ, Shapefiles, GeoJSON and many otherformats.

Installation• Open Google Play Store• Search for SW Maps
• Install and open app• Allow permissions if requested(Android 6.0 and above)

App Navigation
Press to open Drawer(Or slide from left edge)
Change Background Map
Add Recorded or Drawn Feature Layers
Import External Layers (Mbtiles/KML/SHP..)
Add Layer Attributes

Create or Open Projects

Connect External Receivers(Bluetooth OR USB)
Record Features and Tracks

Display GPS/GNSS Data
(Position, Time, DOP…)Show Satellite Skyplot

Scroll Down for More

Take Geotagged Photos
Import Projects andTemplates from Device Storage
Upload Data to FTP Server
Share data to other users
Export to device storage
As KMZ, SHP, Excel…
Save and share layer definitions
as a template for other projects

SW Maps Folder
All exportedfiles saved here
Photos andVideos taken bySW Maps
RAW GNSS Data
(UBX, SBF..)
Copy project
templates hereCopy GIS Data files(Mbtiles, KML, SHP, GeoJSON…)
to import here, inside format
specific sub-folders
Project files saved here

Layers

1. Press to open Layer sidebar
Maximize/Close Sidebar
2. Change Background Layer

Toggle Track and Photo Point Layers
3. Press + to add layer

4. Select Layer Type(We will add a GPS RecordedFeature layer for recording
features using GNSS)

Add GPS/GNSS Recorded Feature Layer

Enter Layer Name
Geometry Type
(Point, Polyline or Polygon)
Change Map Symbol
Then Add Layer

Feature Attributes125Also try adding a Photo Attribute34

Connecting u-blox External Receiver• Connect u-blox receiver to phone USB port
using OTG cable (You may also need toenable OTG Storage in some devices)• From Navigation drawer, select USB SerialGPS. List of connected devices will appear.
• Select u-blox GNSS receiver• Set Instrument Model to u-blox• Check Log to File
• Set Instrument Height• Press Connect
Coordinates Here

GNSS Data and Skyplot• ubx and sbf files are saved in SW_Maps/RawFiles Folder

Record Feature
Select Layer
Type in featureremarks (if required)Enter Attribute Data
(Photos can only betaken after recordingthe feature)

Enable/Disable
Location Averaging

Record PointDrawing Features
1. Add a Drawn Feature Layer
Name: Area
Type: Polygon

Drawing Features

3. Feature
Name
4. Press to Add
2. AddFeature
1. Open
Draw Menu

6. Tap on
map to add
vertices

5. Press
Add Point
7. Press to CloseTap a feature point to open its properties.
You can edit attributes, delete vertices orget directions to a point using GoogleMaps.

Exporting Data

Things to Try• Record a Line Feature• Record a Polygon• Add an Options Attribute Field (Dropdown choices)• Edit attributes after saving feature (Hint: Tap the feature on map)
• Take a Photo Point (Select Photo from drawer)• Record a track• Export data to KMZ, copy to computer and open in Google Earth• Measure length and area by drawing lines and polygons

Templates• Projects once created can be exported as a template for otherprojects.
• Useful when many surveyors and instruments are deployed to collectthe same type of data
• Templates can be made on a Windows PC using the SW Maps
Template Builder tool, or exported from any existing project using SWMaps
http://swmaps.softwel.com.np/template_builder

Template Builder

Exported KMZ in Google Earth
Drone Imagery Mbtiles

Shapefile Categorized Styling

User Manual• SW Maps
http://swmaps.softwel.com.np/assets/resources/manual.pdf• Template Builder
http://swmaps.softwel.com.np/assets/resources/TemplateBuilderManual.pdf

Rtkdroid: RTK in Android• Android app for low cost RTK• Currently under testing, not distributed to public• Uses u-blox receiver connected via USB for rover data, RTCM 3 fromNTRIP for correction• Uses RTKLIB 2.4.3b31 for RTK processing• Sets location of Android device using a mock location provider so allother apps use RTK positioningSet Rover Mode
(Single/Kinematic/Static)

Ambiguity Resolution Mode(Continuous/ Instantaneous/ Fix and Hold)

Select GNSS Satellites to use
Data Output rate
(Position fixes per second)Enter NTRIP Caster Settings
Press to Start RoverPosition Output

Files being recorded(File Size)

Start/Stop Recording

RtkDroid• For installation files and more information, contact Dr. DineshManandhar at dinesh@iis.u-tokyo.ac.jp• YouTube Video Demo
https://www.youtube.com/watch?v=Z_C33io_8S4

Thank You