Importing or loading data is fundamental to any procedure or workflow in Global Mapper. While the process of importing is very straightforward, there are a few variations on this theme that we will explore in this section.
If you haven’t already downloaded the sample data files, they can be downloaded by clicking here. After downloading, unzip the Intro to Global Mapper folder and copy it to your desktop or some other convenient location.
To demonstrate the various ways in which data can be loaded into Global Mapper, we will load several layers covering a specific location. After beginning the process by importing individual layers, we will add multiple files simultaneously from a specified directory, and we will conclude this lesson by creating a new layer from a list of coordinates.
Loading Individual Files from the Introductory Screen
- From Global Mapper’s introductory screen, click the Open Data Files button
- In the resulting dialog box, navigate to the following folder:
*Intro to Global MapperDataTerrain
- Select Black Mountain Terrain.gmg and click the Open button
Note that the layer is listed in the Control Center to the left of the map view.
The Global Mapper Grid (.gmg) format is raster elevation data that is displayed using the default elevation shader.
Loading Individual Files from the File Menu
- From the File menu, choose Open Data File(s)…
- In the resulting dialog box, navigate to the following folder: *Intro to Global MapperDataTopographic Map
- Select Black Mountain Topo.tif and click the Open button
A scanned version of a topographic map is displayed on top of the terrain data
Loading Individual Files by Dragging and Dropping
- In Windows File Explorer, navigate to the following folder: *Intro to Global MapperDataParcels
- Drag and drop the Black Mountain Parcels.shp file unto the map window in Global Mapper
A new vector polygon layer containing the property boundaries is now displayed in the map view
In the Control Center, you can simply uncheck a layer to temporarily remove it from the display or select a layer and use the Delete key on your keyboard to permanently remove it.
Loading All Files in a Folder
Unlike in the previous examples in which individual layers were imported, this workflow introduces the process of choosing a folder containing a large number of layers, each of which is loaded unto the map.
- From the File menu, choose Open All Files in a Directory Tree…
- In the resulting dialog box, locate and select the following folder: *Intro to Global MapperDataImagery
- Click the OK button and in the resulting dialog box, type *jp2 in the filename mask field
This ensures that only files ending with those characters will be loaded
- In the Group Name field, type Black Mountain Imagery
This will create a collapsable tree view containing all of the imagery layers
- Click the OK button
- In the Control Center, click the + sign next to Black Mountain Imagery to display each of the individual layers in the group
A Group can also be created from multiple layers that are already loaded and displayed in the Control Center. This can be done by holding the Shift key to select the required layers, right-clicking within the Control Center, and selecting GROUP.
Importing a List of Coordinates
It is common for geospatial data to be stored as a simple list of coordinates with corresponding attributes. The process of importing data in this format requires certain parameters to be established to ensure the data in the source file is interpreted correctly. In this example, we will create a point layer from a text file containing a list of latitude and longitude values.
- From the File menu, choose Open Generic Text File(s)…
- In the resulting dialog box, navigate to the following folder: *Intro to Global MapperDataBuildings
- Select Black Mountain Buildings.txt and click the OK button
- In the Import Options dialog box, apply the following parameters:
- Import Type: Point Only
- Coordinate Order: Y/Northing/Latitude Coordinate First
- Coordinate Format: Default
- Fields to Skip at Start of Line: 0
- Rows to Skip at Start of File: 0
- Coordinate Delimiter: Tab
- Include attributes… : Check this box
- Column headers… : Check this box
- Treat 3rd coordinate value as elevation… Uncheck this box
- Leave all of the other settings in their default state and click the OK button
- When prompted to enter projection information, click the Search by EPSG Code button and type 4326
This automatically applies the projection parameters for WGS84
Recently loaded files are listed at the bottom of the file menu. This offers a convenient way to access frequently used layers.
Before concluding this section, we will save a workspace file that maintains a record of the layers that have been loaded along with any layer-specific settings that have been applied. Workspace management will be covered in much more detail later in this course.
- From the File menu, choose Save Workspace…
Note that you can also use the corresponding toolbar button and keyboard shortcut (Ctrl +S) for this purpose
- In the resulting dialog box, navigate to the following folder: *DesktopIntro to Global MapperMy Maps
- Name the file Black Mountain and click the OK button
It is important to note that after loading layers into Global Mapper, an active connection is maintained with the source files. Therefore if this directory path is changed in any way, such as by renaming or moving the files or folders, the data will not be displayed in Global Mapper and an error message will be generated.
- With support for over 300 unique file formats, loading data into Global Mapper is a straightforward process.
- In most cases, the data will be loaded automatically, however, there are certain formats that require a degree of manual intervention.
- A record of the layers that are loaded, as well as any display settings, is stored in a workspace file.
- Click here for more information