February 1, 2022
Thank you to all who attended the virtual GeoTalks 2022 conference! With wonderful presentations by GIS and research professionals along with our own Blue Marble experts, we received many questions throughout the day. Questions for the guest speakers Larry Mayer, Brett Rhodes, and Paul Seeman have been sent to the presenters. Below are the answers to common questions asked to our Blue Marble speakers about all the Blue Marble programs.
Will this presentation be available to view later?
Yes, all the presentations at GeoTalks 2022 were recorded and will be available to view later. As a registered attendee, you should receive an email when the recordings are posted and available to view.
If you did not register for GeoTalks 2022 but would like to see the recorded presentations, please register here.
Global Mapper Pro
Is the Global Mapper Pro license separate from Global Mapper and the Lidar Module?
With the release of Global Mapper version 23.0, we retired the Lidar Module and it was replaced with Global Mapper Pro. If you are still using an older version of Global Mapper you may still have the Lidar Module, but when you upgrade to the current release, you will have Global Mapper Pro.
Global Mapper Pro includes all the tools in Global Mapper, the tools previously in the Lidar Module, and some new tools pertaining to advanced terrain analysis, point cloud editing, and workflow optimization.
Your version appears to be 23.1. We are still at 23.0, do the same procedures apply to this version as well?
All the tools demonstrated and shown are available in the current release, Global Mapper Pro version 23.0. Version 23.1 is currently in the beta period. If you would like to participate in this beta and provide us with some feedback on new functionality, please contact beta@bluemarblegeo.com.
How does one create a Global Mapper Package (*.gmp) of data in a workspace (*.gmw)?
Global Mapper Package (*.gmp) files efficiently store multiple types of data in a single file that can be shared or used in other projects. To create a Global Mapper Package from a workspace, use the checkboxes in the control center to enable the display of the layers you would like to export, and from the File Menu select Export > Export Global Mapper Package File. The displayed layers will be exported to a single file that can be loaded into the open workspace or a new one.
Lidar and Terrain Analysis
Can you conflate the different breaklines for the image or the mesh creation to determine errors between results?
Extracted breakline features are vector features and once created, can be edited, combined, searched, and used within any of the Global Mapper Digitizer tools. Extracted and edited breaklines can then be exported or used in the creation of new terrain layers. Additionally, there are tools in Global Mapper Pro to detect change by comparing and calculating volumes between elevation models.
How do you generate a curvature grid?
A curvature grid n Global Mapper can be generated with the Create Curvature Grid from Terrain Layer(s) option in the Analysis Menu. The generated curvature grid will be shaded with the built-in curvature shader.
Is there a tutorial video available for the building footprint and tree extraction?
A demonstration of building extraction can be found here in a portion of a previous GeoTalks Express webinar. Tree extraction, part of the same feature extraction tool, is demonstrated and explored in this Ask the Experts video.
In Katrina’s talk, she showed raster vectorization and a result showing a possible 3D view. I presume the imagery was combined with elevation/Lidar data together?
The Vectorize Raster tool works with both 2D raster image layers as well as 3D elevation models. The polygons resulting from the vectorization of a 2D image will be 2D features with no elevation values, but when working with an elevation model, if elevation values are used for vectorization, the resulting polygons inherit the average elevation of the bounded area as an attribute.
Do you expect to be providing processing capabilities for lidar sensors in the future as part of Global Mapper Pro?
Point clouds collected with lidar sensors can be classified, edited, and analyzed in Global Mapper Pro with the suite of lidar analysis tools. We are always working to improve and expand this set of tools to better process point cloud data.
Is there an easy way to shrink or enlarge the points in the 3D view of a point cloud?
By default, the point cloud returns are resized in 2D and 3D based on the area and density of points being displayed. This option can be changed for a point cloud layer on the Lidar Display tab of the Layer Options. Under Point Size, you can choose to always draw points at a fixed size in pixels.
Python
Are there planned Global Mapper Pro Python classes or how-tos?
Currently, there are no Python training classes planned. A short video demonstrating Python in Global Mapper Pro is available here, and full documentation for the Python integration in Global Mapper Pro can be found here.
Can you possibly provide a library of common Python scripts to current users to benefit from? The .las to .dem would be a great example, for instance.
While a library of common scripting tasks is not available, the knowledge base for the Global Mapper Pro Python integration does include some sample scripts here.
Pixels to Points
Is Phodar a real term? Or coined by Blue Marble Geographics?
The term phodar has been used outside of Blue Marble as a shortened way to refer to a photogrammetrically derived point cloud, although it is not as widely used as the term lidar.
I’ve not yet worked with images. How does the image contain elevation if you use an image from the internet? And do all drones include elevation data seen in Mackenzie’s attribute column?
Drone-collected images are typically geotagged images, meaning that each image holds the 3D coordinates of the camera position when that image was captured. These image/camera coordinates are used to position the picture points on the map when they are loaded into Global Mapper Pro, and they are listed in the Input Image List of the Pixels to Points tool.
If your images do not contain internal position information, you won’t be able to load them directly into the map view of Global Mapper Pro, but you can still use them with the Pixels to Points tool. When loading non-geotagged images into the Pixels to Points tool you will be warned that some or all images do not contain coordinate information and you may also be prompted to enter camera information for the images. From the Input Image List, you can then load position or coordinate information from the images from an external file, or try to process the images without any coordinate information. With no coordinate information for the Pixels to Points tool to use, the generated outputs may not be as well constructed, and they will be placed at an arbitrary location.
What key features in the input enable the creation of the point cloud and mesh/3D model? If not assuming wrongly, I only see one piece of lat/long information with one elevation type per image.
You are correct that each image in the input image set only contains one set of coordinates describing the location of the camera when the image was captured. Along with this location the image stores camera and position angle information in the file metadata. All of the information together is used by the Pixels to Points tool.
The driving method behind the 3D reconstruction in the Pixels to Points is the Structure from Motion (SfM) process. This process identifies features in overlapping images based on recurring pixel patterns and uses the image data, position, and camera metadata to place the identified feature as a point in 3D space. With this process, the Pixels to Points tool is able to take the original set of overlapping, geotagged images and create 3D outputs like a point cloud and 3D mesh.
How long did the processing take in real-time?
To process this set of images on my machine took a little over an hour. Processing times will vary depending on a myriad of factors including machine processing resources and memory, analysis method and other options selected in the Pixels to Points tool, and of course the size and number of images in the input image set.
Options in the Pixels to Points setup like reducing the input image sizes, enabling clustering, and saving temporary files as the process runs may help manage the resources and time used by the Pixels to Points tool.
What is the largest drone photo data set you have seen successfully run through the Pixels to Points tool? Do you have a recommended number of photos not to exceed?
Global Mapper users have run sets of hundreds of images with Pixels to Points. The general guidelines for input images can be found here in the Global Mapper knowledge base. It is also important to note that we recommend processing images that were all collected on the same flight to help standardize lighting, altitude, and camera information.
The limitations on the size of the input image set do mainly depend on the quality of the images and the machine resources you have available. Pixels to Points is a heavier process and does require a fair bit of machine memory as it runs. While there is the option to reduce the image sizes to reduce the needed memory, downsampling the input images too much will cause a loss of detail and that will be reflected in the generated layers.
Can you bring in a text file for the drone control points?
Yes, you can absolutely load ground control points into the Pixels to Points tool from a text file. Right-click in the Ground Control Points box and simply choose to Load Control Points from Text File. It is also worth noting that points can be loaded from a text file into the Global Mapper main view and displayed as a layer alongside any other reference layers.
I assume that the ‘New Mask’ button will allow a polygonal mask to be applied to images to exclude the masked area (any moving object) from the process?
Yes, the New Mask option in the Pixels to Points tool allows you to select a portion of an input image that should not be considered in the Pixels to Points process. Options to create a mask by drawing a polygon or based on similar colors are available.
How can the masking tool in the Pixels to Points tool work with photos with sky in them?
This is a great use case for the masking option in Pixels to Points. Areas of sky typically do not reconstruct well in the Pixels to Points tool, and you generally do not want them included in the generated outputs. Masking allows you to draw a polygon on an image or select a specific color in the image that should not be included in the processing of the image set. Look for a drop-down section here in the Global Mapper knowledge base for examples using the masking tool.
Is there any capability in editing the orthoimage around building corners to clear up blurriness or the unclean rendering of the corners, etc.?
While there is no method to select and edit individual pixels in an image, you can project some of the individual drone-collected images as layers in the workspace by selecting a specific picture point and using the right-click option to Load Selected as Orthoimage (see Generate Quick Rectified Images here). Choosing to do this for key images in the set that are centered on the building or feature you would like to correct then allows you to use image cropping and feathering options to blend the image layers together. The image layers now displayed together in Global Mapper can be exported using the File Menu > Export > Export Raster/Image Format option to create a single corrected image layer.
Map Layout Editor
The legend extends beyond the graphic. Can it be resized to show the entire legend?
Yes, all elements in a Map Layout can be resized and repositioned. Set a specific size and/or position with a right-click to access the element properties, or select and drag a corner or side of the element to resize it.
Can these be saved as georeferenced PDFs?
Yes, the pages designed in the Map Layout Editor can all be exported as geospatial PDFs. Export options from the Map Layout Editor can be found in the File Menu of the layout editor dialog.
Is the geodesy of the map also an insert?
The coordinates noted around the data display in the layout are enabled by editing the properties of the Map View element. Additional Map Layout Elements can be added to any page, including images, text, a scale bar, and a legend.
Can you work towards providing stock map templates to choose from when creating maps?
Global Mapper does come with some Map Layout Templates that you can use to begin creating your maps. These templates are installed in C:\Users\USERNAME\AppData\Local\GlobalMapper\MapLayoutTemplates and can be selected for use when creating a new layout.
Global Mapper Mobile
May the transfer package be sent to another Global Mapper computer? I use a Windows 10 tablet for my fieldwork with a full license.
A Global Mapper Mobile Package (*.gmmp) or a Global Mapper Package (*.gmp) can both be loaded into a full installation of Global Mapper. Feature Templates, while designed with Global Mapper Mobile in mind, can be used in Global Mapper to collect data as well. Additionally, Global Mapper does support the connection to external GPS units to record tracks and waypoints.
Geographic Calculator/GeoCalc Online
How will you continue to support proprietary client-based datum definitions and shifts? Will it continue to be at the project level?
Custom objects including datum and transformation definitions can be added to the Datasource for your installation of Geographic Calculator. These definitions can then be exported and shared with members of your organization in a variety of formats.
Do you intend to support all the new IOGP positional exchange formats; including P7?
We have followed the development of the updated P formats and presently support P1/11. We have not yet received requests for any other formats as it has seemed there has been slow industry uptake of these formats.
Is the area of use based on the bounding box or area polygons in EPSG/IOGP?
The area of use for objects in Geographic Calculator and GeoCalc Online are based on polygons. Irregular polygons are displayed in Geographic Calculator while bounding box areas are displayed in GeoCalc Online.
