Taking GIS Data into the Field with Global Mapper Mobile
Departments of Transportation have the ever-important job of developing and maintaining the nation’s road infrastructure. With the public roads network stretching to all corners of this country, transportation departments need to be able to take data into the field to assess and update assets as needed. Working with libraries of existing data and GPS-enabled programs, surveyors and inspectors can use the Global Mapper toolkit to accurately record features and update maps.
As a GIS application, Global Mapper, has wide-ranging capabilities for data visualization, editing, and management. Loading existing maps and data layers into a workspace allows users to explore the existing infrastructure and through terrain editing tools, like terrain painting, plan for upcoming projects. While GPS devices can be connected to a machine running Global Mapper and used to create new data, Blue Marble also offers a mobile solution for field data use and collection.
Global Mapper Mobile makes it easy to take data into the field on a smaller phone or tablet device. Available on Android and iOS devices, the app displays reference data and can be used to edit existing data and collect new data. Modern phones and tablets are GPS enabled and Global Mapper Mobile works with the internal location services of the device to locate the user on a loaded map. This internal GPS information can be used to simply view the user location or record new features.
Creating a Map and Loading it into Global Mapper Mobile
Backing up a moment, let’s discuss the process of creating a map and bringing it into the mobile app. With desktop and laptop machines being more powerful than most mobile devices, the mapping process starts in Global Mapper desktop. Load existing data layers into Global Mapper and edit or create any data if applicable. In a Global Mapper workspace, you can apply raster and terrain display options as well as style options for vector layers. Starting the map creation in Global Mapper desktop allows users to load and explore much larger maps than are likely needed in the field. If necessary, Global Mapper can then be used to trim down the dataset to a region of interest for field work.
Below, a simple map is created for all public roads in a district of Maine. The vector styling for the roads is determined by the attribute describing the road surface type. In this map and workflow, the concern is the unimproved roads. In a four-season climate, winter temperatures and the melting of snow in spring often cause potholes and ruts in dirt or diminished roadways. These rural public roads are important arteries to the residents of an area and typically need some level of routine, yearly maintenance.
Data is loaded, styled, and explored in Global Mapper before being packaged up and sent to a device in the field.
A featureless template for a layer can be added to the workspace from the Feature Templates section of the Configuration dialog in Global Mapper. A Feature Template is simply the structure for a layer, indicating the feature type, style, and a structure for the desired attributes. Creating a layer from a Feature Template in a workspace allows this layer plan to be shared to Global Mapper Mobile and used for standardized data collection.
To package the vector layers and raster base map up for use on a mobile device, the map is exported to Global Mapper Mobile format. This export creates a Global Mapper Mobile Package file (*.gmmp) that efficiently packages up raster, vector, and elevation layers into a single file for easy sharing to a mobile device. Sharing data to a mobile device can be done through an email attachment, a cabled file transfer, or via a shared drive such as Dropbox or Google Drive.
Opening and Orienting a Map in Global Mapper Mobile
With a Global Mapper Mobile package transferred to the mobile device, this file can be opened directly through the Global Mapper Mobile app. Opening the app and tapping to Open Map will open a screen to browse the file storage of the device and import a map.
The map open in Global Mapper Mobile contains the data layers exported from Global Mapper desktop.
Like Global Mapper desktop, Global Mapper Mobile contains a Control Center that lists the layers present in the map. Tapping a layer listed in the Control Center will hide it from view and the vertical dots to the right open the layer options that include actions to reorder layers in the map.
Through the Control Center in Global Mapper Mobile the layers can be hidden or reordered. GPS location of the device and user can be enabled for display on the map from the Location Display menu.
Next to the Control Center is the GPS display. Enabling a GPS option will, by default, use the internal location services of the mobile device to display the GPS location on the map and note the coordinate location and accuracy of this measurement on screen. The display of the GPS location can help orient users in the field and better inform them of nearby features. While cell service and wi-fi connection can increase the accuracy of the GPS location identified with the mobile device, it is not essential to display the location.
Since the accuracy of a mobile device’s internal GPS may not be up to the accuracy standards of an organization for data collection, Global Mapper Mobile with a Pro Module subscription can connect to and use an external GPS device. From the Main Menu, in the upper-right corner, the Advanced GPS option allows the selection and use of a Bluetooth connected GPS device. The use of an external device will increase the accuracy of the location, and that is reflected in the GPS information displayed on screen. Additionally, in the Advanced GPS options, the satellite connections, advanced location information, and raw NMEA stream can be viewed.
To locate a specific road feature in the loaded map, vector features can be searched in Global Mapper Mobile. From the bottom-left of the screen, tap to change the toolset and select Search Features. To initialize a search, tap the magnifying-glass, search icon in the bottom-right.
At the bottom of the Search screen the feature type being searched can be specified. To search the road features, the search of Areas and Points are disabled. Back in the top half of dialog, an attribute can be selected and this selection dynamically updates the list of available values. Selecting the surface type attribute and the ‘Unimproved’ value will identify all unimproved roads. Tap OK to return to the map view and see the features selected. This visualization depicts the rough cover roads that may need inspection and maintenance. To identify a single road that will be inspected imminently, the search tool can be used again to search by the street name and ultimately select the single feature.
A search for all line features with the surface type value ‘Unimproved’ selects all unimproved roads on the map.
Editing and Creating Data in Global Mapper Mobile
To select a feature, view attributes, and edit vector data, the Digitizer tool must be selected from the Toolbox accessed from the bottom-left corner of the opened map view. Selecting the single pencil, digitizer icon, vector features can now be selected with a single tap. A second tap on a selected feature will open the feature information to display the attributes. From here values can be edited and tapping to view the vertices will allow the edit of the feature geometry.
With the digitizer select tool active, tapping once on a feature will select it. Tapping again on the same feature will open the feature information for viewing and editing.
To create features with the digitizer toolset, and tap to enable the point, line, or area create tools. Each of these tool buttons will open a menu prompting a selection of the specific feature creation method. While a manual tap can be used to draw and place features on a map, when working with a smaller screen on a GPS enabled device, the options to record a feature based on GPS location are far more appropriate.
To record the track for an undocumented or altered road, a line feature creation mode is used to either record vertices along the line at a specific distance or time interval. Tap the data creation method to start digitizing the feature and when the end of the road is reached, tap the checkmark to finish the creation of the line.
A line created with any feature create mode can be placed in an existing layer, a new layer, or a feature template layer.
Just like in Global Mapper desktop, when the geometry of a feature is created, the user is prompted to enter the feature information. A layer for the feature is selected, and if a Feature Template layer is selected the app will prompt the user to enter any required attribute values as set up for the template in Global Mapper.
Another type of data that can be captured and added to a map in Global Mapper Mobile is a picture. Using a long-tap gesture on the map view, the device camera will be launched allowing the user to capture a picture in the field. The captured image will be geotagged and will appear on the map as a Picture Point feature at the GPS location. The image is now embedded in the map through a vector point feature and will be saved with the map. Being able to record a visual of the field can help to supplement any notes and feature attributes added to the map to create a fuller picture of the roadway of interest and the maintenance that may be required.
Adding an image to a map is a valuable way to capture a project site or convey additional information.
Saving and Exporting Data to Global Mapper
If data was collected or changed, the mobile map can be saved on the device through the Global Mapper Mobile Main Menu. The file can then be exported via email or moved to a shared drive or moved to a desktop or laptop machine with a cabled file transfer. Any data added or changed, and any images added to the map will be saved and exported with it in the Global Mapper Mobile package format (*.gmmp).
The Global Mapper Mobile package is then loaded into Global Mapper, and the altered data can be explored, styled, and analyzed as needed. Images captured in the field are now part of the map in Global Mapper and the feature info tool can be used to open and view them.
The original data along with created data and added image is transferred from the mobile device and opened in Global Mapper desktop.
With the infrastructure created and maintained by the department of transportation, work to locate, survey, and note the condition of existing features is essential. Global Mapper and Global Mapper Mobile provide a congruent system to move data from the office, into the hands of field surveyors in an interactive and editable format for consistent data visualization and collection.
If you are interested in Global Mapper, download a 14-day free trial today. Global Mapper Mobile can be found in the iOS App Store and Google Play Store as a free download. If you have any questions or if you would like a demo, contact us!