GeoTalks Express – Session 4 Questions & Answers

The fourth of Blue Marble’s GeoTalks Express online webinar series entitled Ask the Experts was conducted on May 6th, 2020. This one-off event offered an opportunity for participants to submit questions, many of which were answered during the live session. Due to the volume of questions that were received, not all questions were answered during the webinar. The following is a list of all of the questions and the answers provided by Blue Marble’s technical support team.

 

Can you provide an overview of scripting? 

Global Mapper script is a very useful way to create and run a workflow through an open Global Mapper workspace, or without having to open the user interface. There is a scripting reference section in the Global Mapper knowledge base that you can find here (there is also a PDF version). 

 

Can we view more than one surface in the profiler?

Yes, if you have overlapping terrain surfaces loaded into Global Mapper, you can view both of these in the Path Profile tool by enabling the option to Draw Separate Line for Path from Each Terrain Layer in the path profile settings

 

How do I stop Global mapper from defaulting to meters when I load data? 

The units displayed for measurements can be set in Configuration. In Configuration > General > Measure/Units change the Distance Units setting to set the units for all horizontal digitizing and measuring tasks in Global Mapper. To set the vertical units to display, go to Configuration > Vertical Options and change the Elevation Display/Export Units setting. 

 

How can I make scripts or small programs that can perform inside the platform?

You can use a Global Mapper script to run some processes with source data or run them in a workspace using loaded data. Additional information on Global Mapper Scripting can be found in the scripting reference section of the Global Mapper knowledge (there is also a PDF version). 

 

How do you make different color dots? I can not seem to find the option to make various color dots, other than those existing. 

To make custom color dots for vector point features, go to the Point Styles tab of the vector layer options and when setting the style, select <CUSTOM_DOT_SHAPE> from the Select Point Symbol drop-down menu. You will then be prompted to enter the dot size and select the color for the point symbol. 

You can also add custom point symbols in Configuration > Styles > Custom Symbols. These will then display in the Select Point Symbol dropdown menu when setting the point style for your features. 

 

Is there a way to copy-paste path profile sections data from a table without having to export the file? 

Currently, there is no way to view the Path Profile sample information without exporting the path. From the File menu in the path profile dialog box, you can Save Profile Line(s) to New Layer and this will add a layer to the workspace containing the path profile line as a 3D line feature that you can work with in Global Mapper. 

I have written a request ticket (#GM-11003) about adding a way to view and copy the path profile samples from the Path Profile view without having to export the path. The Blue Marble development team will look into this request and I will let you know when I hear any updates on this matter. 

 

What is the best way to bring in elevation point data at 1 meter spaced points and then export it as 5 meter spaced points?

With your data loaded, you can create an elevation grid from your points. You can specify your desired spacing of 5 meters when generating the grid, or you can generate the grid at a finer resolution and downsample when exporting. Export the generated grid to a point format or text format, like XYZ grid, and specify a resolution of 5 meters in each direction to create a file with 5 meter spaced points.

 

Would you Classify each UAV LiDAR flight line point cloud before using the fit to cloud feature? 

The answer to your question is somewhat dependent on your data. If you can accurately classify the point clouds from the flight lines individually it may help to create a better fit between them using the Fit Point Cloud option to Only Match to Closest Points of the Same Class

If you are having trouble accurately classifying the point clouds individually you may want to fit the point clouds together and then classify them as one dataset. This may help with the classification of points along the edges of point clouds where flight lines overlap. 

 

I have a layer of points with an attribute consisting of a link to an image file. How can I activate the link to display the image?

If you have a file or image link in an attribute attached to a vector feature, use the Feature Info Tool to select the vector feature in Global Mapper. This should automatically open the linked file in your system’s default program for the linked file type, and/or display a dialog with a dropdown asking if you would like to see the feature information or open the linked file.

 

How do I take a list of coordinates and convert them?  Say i had point data that i want to convert from lat/long to UTM 27 – 10?

After you load your latitude/longitude data into Global Mapper, you can reproject it by changing the workspace projection in Configuration > Projection. UTM zone projections are supported in Global Mapper. After you have changed the workspace projection, export the data to your desired format. The data will be exported using the projection you set in Configuration > Projection. 

 

If I import shapefiles in Global Mapper having exported them from other software such as Model Maker, I lose text labels. 

How were your features labeled in Model Maker? Are the feature names contained in an attribute? To view attributes for a layer of features, right-click on the layer in the Control Center and select Edit Attributes

To set the labels for features in Global Mapper, open the Vector Options, and on the Labels tab, you will have some options on how to label the features. Make sure the box to Display Labels for this Layer is checked, and set your label preferences for the layer in this dialog. To use an attribute value for the feature labels, select the option to Use Selected Attribute Value, and select the desired attribute from the dropdown menu.

 

How can I use Google Earth coordinates in the View Shed tool easily without always pasting in Lat & Long?

In Global Mapper, if you have a point feature selected when you click on the map with the Viewshed tool, you will be asked if you would like to use the clicked location or the location of the selected point for the viewshed creation. In order to use coordinates from Google Earth, you can create placemark point features in Google Earth and save them to KML/KMZ format. You can then load the KML/KMZ file of point features into Global Mapper, select one or many, and use the viewshed tool choosing to use the selected point(s) for the viewshed creation.

 

Beyond current options, can the pointer info-tips be configured to present other spatial information?

Info Tips in Global Mapper can be configured to show the cursor location as well as a raster pixel values and/or specific attribute values from vector features.

 

Can you select an area in the 3D view and manually classify it? For example, can I select a tower and lines with a manually drawn box and classify it as power lines?

 

While Global Mapper does not currently support sweep selection in the 3D viewer, features can only be selected individually through this viewer, you can use the Path Profile tool to select and manually classify points from your point cloud. 

Using the Path Profile tool you can look at a cross-section of your point cloud and in this view, select and classify the points using the manual classification tools in the 2D map view or the Path Profile window. Points selected in the Path Profile view will also be selected in both the 2D main view and the 3D view in Global Mapper. Through the path profile menus, you are able to set the width of the profile with respect to lidar data to display a narrow or wider section of points in this cross-section view. 

Is there a way to convert GeoPDF files to GeoTiff files in a batch format? One of the issues I have had is getting my preferred layers on and hitting the ignore frames for each and every file. This dialogue box does not allow for the process to run in the background, you have to hit no about every 5 seconds.

You can use the Batch Convert/Reproject tool to convert Geospatial PDF files to GeoTIFF files, but this method does not provide any import options for the PDF files. 

When loading Geospatial PDF files into Global Mapper use the checkbox option to Use these options for all operations at the bottom of the PDF import options dialog to apply the selected layers to render and other load options to all PDF files you are loading. 

 

Is there a way to convert GeoPDF files to GeoTiff files in a batch format? 

You can use the Batch Convert/Reproject tool to convert Geospatial PDF files to GeoTIFF files, but this method does not provide any import options for the PDF files, but by default, multiple frames are ignored.

 

Can you help with ground/building extraction parameters in the Lidar Module? Large flat buildings are my foes. 

The parameters you use to classify your point cloud do vary based on your data and the characteristics of your study area. When classifying ground in Global Mapper be sure you are entering an accurate Maximum Building Width value as this will help to keep the tops of large flat buildings from being classified as ground.

Once ground points are accurately classified move on to the non-ground classification. Increasing the Max Co-Planar Angle Difference a bit may help to keep points from the tops of buildings being misclassified as vegetation.

Once your point classifications are accurate, the extraction of the features will yield much better results.

 

Is there any chance future versions of Global Mapper 64bit will offer the option to export gdb format?

In version 21.0 of Global Mapper, the ability to export vector features to a Geodatabase was added to the 64-bit version of the program. The 32-bit version of the Global Mapper can export raster layers to a Geodatabase if you have an ESRI license on your computer. 

 

Is it possible to do feature extractions, e.g., topographic lineaments?

Topographic features can be visually identified in an elevation grid layer of the ground surface. From an elevation grid, you can generate contour lines of the area to help identify and quantify the topographic changes associated with specific features. 

Using the Lidar Module, you can use the custom feature extraction tool in the Path Profile window. This function may allow you to manually extract lines for the edges of your features. 

 

Can Global Mapper perform a coarse cross-section analysis?

The Path Profile tool in Global Mapper allows you to view and analyze cross-sections of gridded elevation data and point clouds by drawing a line across your loaded data. In the settings for the path profile tool, you can adjust the sample spacing with respect to the terrain data. This allows you to look at a finer cross section line made up of more samples, or a coarser estimation based on fewer. 

 

What file formats can Global Mapper convert?

Global Mapper supports hundreds of formats for both import and export. A full list of the support file formats can be found here in the Global Mapper knowledge base

 

Are there workflow building tools available in Global Mapper similar to Model Builder in ArcGIS?

​Global Mapper supports many tools and processes through its command-based scripting. With Global Mapper script you can list commands for the Global Mapper program to run and execute these tasks through the Global Mapper user interface using loaded data, or by calling data in the script and running without using the interface of the program. 

Global Mapper script allows you to design a workflow and run it over your data automating some repetitive analysis tasks, similar to the Model Builder in ArcGIS.

 

How can I view/isolate individual features in a layer?

You can right-click on the layer in the Control Center and go to Edit Attributes. You can scroll down the Attribute Editor table and find the specific feature you are looking for. You can right-click on it to edit the feature and you can also see many other options in regards to the one feature. Use Ctrl+C or Ctrl+X to copy or cut the selected features and Ctrl+V to paste them to a new layer.

 

Can I run Global Mapper license server on AWS, So we do not have to use VPN to connect to the server?

While Global Mapper officially supports the tools on physical Windows machines, there are many users successfully running the tools on cloud servers. In these instances, it is important that the version of Windows you set up must have a stable machine ID and server name, as those are used in the license. You’ll also want to make sure the server is seen as part of your internal network. On AWS your security groups and firewall will need to allow access on two ports (both of which you can customize if necessary), and have exceptions for the few tools that run (lmgrd.exe, bmgeo.exe).

If you’re interested in testing this, I would recommend emailing the Blue Marble Sales Team (authorize@bluemarblegeo.com), explaining you’d like to test moving your license to a cloud server and provide them with the server machine ID and server name. They will then get you a temporary license with which you can test.

 

Is there a EPSG code for State Plane Alabama West NAD83 “Feet (US Survey)”. Only related codes found are 26730 and 26930, but not NAD83 Survey Feet.

When choosing your projection in Global Mapper, you can switch the Planar Units to FEET (US Survey). In the Configuration > Projection tab, choose State Plane Coordinate System under Projection dropdown. Then choose zone Alabama West. Then choose NAD 83 as your datum. Then under Planar Units, choose FEET (US Survey).

 

​When creating a grid for creating contours, at times I have to set it loose enough that it creates a grid and associated contours well outside of my desired area which then take much time to clean up. My question is, can I limit the area within which the grid, and then contours are created​?​

​There is a Grid Bounds tab in the Elevation Grid Creation Options window which allows you a few different options to constrain the grid creation. The contours then should be limited to the area that you have gridded.

What is the best way to smooth contours while losing the least accuracy​?​

Your best option would be to start in the Simplification tab and set the simplification to 0.00, all the way to the left. After the contours are created, you can manually adjust the smoothness of the contours, by selecting all features with the digitizer tool, then right-click in the main window, and go to Move/Reshape Features and pick SMOOTH.

 

“Is it possible to Remove the default Point, Area, Line Types from the configuration, We create our own set of types but all the other items interfere with workflow at times.”

Yes, this can be done by going to Configuration > Vector Display. Under ‘Filter’ you can choose Area, Lines, and Points as needed and filter out certain types. However, certain actions in Global Mapper utilize certain built-in types by default. I would recommend at least keeping “Unknown” points, lines, and polygons visible.

 

“Is it possible to manipulate the .dbf file (from your shapes) in Excel then convert it back to a workable dbf file in GM?”

This would be functionality independent of Global Mapper, or any other GIS which writes DBF files. Excel used to support the DBF format, allowing you to open and edit those files. However, I believe in the last few years, Excel has dropped that support. If you needed to edit attributes in a file, what you could do is open the Attribute Editor in Global Mapper and edit the data there directly. Alternatively, the Attribute Editor has a Save to CSV option so you could save that data to CSV, work with it in Excel, and then Join it back to the data in Global Mapper.

 

“Good morning, I want to ask how I can insert break lines (rivers and roads) when generating a MDT in Global Mapper, can this be done?”

Yes, when you’re using Create Elevation Grid this tool has an option “Use 3D Area Line Features as Breaklines”. If you have 3D vector features representing your roads and rivers, the elevation from those features will be included in your resulting terrain layer with that setting enabled.

 

“Is it possible to export vector objects created in the Lidar Module from a classified point cloud? You showed that feature in an earlier webinar.”

Yes, any features you Extract from a classified point cloud can be exported to a supported vector format. The features will be 3D by default so you may want to ensure whatever export format you use supports 3D features.

 

I can do most of my terrain analysis using Global Mapper except finding the shortest path on the terrain between two points.. Have you any plan to add this to the application?

Are you trying to find the shortest path using existing shapefiles on the screen in Global Mapper? Like a road network?  Or strictly just a terrain layer? If yes to my second question, you can simply use the Path Profile tool from the Analysis toolbar, to draw a path between the two points. You can also use the digitizer to draw a line feature between the two points, which should be your shortest path.

 

​Can I associate images to either points or lines in Global Mapper?​

Yes. After creating a point feature, in the Modify Feature Info window that appears, you can click Add File Link(s).. and this will relate it to file on your computer. When you use the Feature Info tool and select the Point feature, the image will open in whatever your default photo viewer is on your desktop. You can repeat this workflow with line features as well. 

In the case of photographs that are already geotagged, such as those taken with a GPS-enabled smartphone, the photos can simply be dragged and dropped unto the Global Mapper map window. A clickable picture point will be automatically created at the precise location at which the photo was taken.

 

How was the Pixels to Points algorithm developed? Was it licensed from somebody else? How does it compare with e.g. Pix4D?

Much of the tools under the hood of Pixels to Points come from openMVG and openMVS. More of this information can be found at our 3rd Party Library page on the User Guide. We do our own development as well to enhance the tool as we see fit from customer feedback and internal testing. 

It is a common question we get asked about comparisons to Pix4D or other software suites like that. Since the Pixels to Points tool is very new to the photogrammetry market, we do not expect all of the processing to meet exactly the same results, of more mature photogrammetric software out there, but many users are satisfied with the results that it creates. I would say we offer the full suite of GIS needs that can be done all in one program from processing your imagery, all the way to developing elevation grids, calculating pile volumes, creating contour maps. My suggestion would be to download a trial version of Global Mapper and test out the capabilities of the Pixels to Points tool against the others. Global Mapper pricing is not based on monthly subscriptions as with other software like Pix4D. With Global Mapper and the Lidar Module, you get a perpetual license that you can upgrade when you like.

 

How do you charge for training?

We have public training and custom training options available with some details described here on our website. For additional information on training curriculum and pricing please contact our training team at training@bluemarblegeo.com

 

I was trying to bring in elevation point data and chose the point option, but I wasn’t able to color classify the data once I had it in – I had to bring it in and choose the lidar data radial dial – is this because it was elevation data? That it wouldn’t classify as just plain point features? It was bathymetry data. 

While you can create an elevation grid from 3D point features, you must load the data as lidar to be handled like a point cloud in order to use the Lidar Module classification tools. 

The difference between loading as point versus lidar data when you import a text file is more about how Global Mapper stores and handles the data internally. When you choose the lidar option, the attribute structure and spatial indexing that are used are necessary for the point cloud classification tools. It’s also a storage structure that better handles visualization of large 3D point clouds. 

 

How can SPLIT function be used in generating map legend results?

Splitting layers in Global Mapper can help with data management and organization, and in a Map Layout  it allows for finer control over the entries displayed in the legend. In the Legend Properties in the Map Layout Editor, you can filter by layer what you would like to show in the legend.

 

​Could you tell me if you can add breaklines before generating the contour lines?

3D line and area features can be used as breaklines when generating an elevation grid. ​You can then create contour lines from your elevation surface that used the breaklines when it was generated. 

 

Are there ways or methods to do NDVI type analysis with SUAS collected RGB based imagery? I am trying to evaluate changing vegetation conditions over time through aerial photo monitoring and wondering about approaches to classify SFM derived orthomosaics to separate out vegetation changes and export as a new raster. Is there something that can be done with changing RGB bands or another approach? I have tried the raster to vector approach without success.

The formula for NDVI calculation is (Near Infrared – Red)/(Near Infrared + Red). If you have only RGB images of your study area you cannot calculate NDVI values as you are missing the Near Infrared (NIR) values. 

Creating 3D point clouds from your sets of drone collected images using the Pixels to Points tool in Global Mapper can allow you to track vegetation growth and expansion. Using the new Compare Clouds tool with point clouds generated from different image sets you can detect change in a vegetated area over time.

 

Can you give an overview of the Generate Watershed analysis with focus on the stream threshold, resolution and depression fill depth?

Details on all of the options for the Watershed Generation tool can be found here in the Global Mapper knowledge base

The resolution settings determine the resolution used to look at the terrain data in the watershed generation process. The default values should be the resolution, pixel size, values from the elevation data layer. Increasing these resolution values will lower the resolution used to look at the terrain decreasing the processing time but causing some loss of detail.

The stream threshold value determines the amount of water that must run through a cell in order for it to be considered part of a stream. Entering a larger value here will mean more water must flow through a cell for it to be considered a stream, resulting in only larger waterways in the output. Using a smaller stream threshold value will result in more minor waterways and streams in the output. 

The depression fill depth is used to determine the depth of depression in the terrain that is allowed to be filled and have water spill out of it and continue flowing. Depressions deeper that the entered fill depth will be considered basins and flow will terminate there. 

 

What are the best ground classification settings for steep terrain with tall, dense, evergreen trees? 

The parameters used in the automatic ground classification tool, and any other automatic analysis tool, depend on your particular dataset and study area. With an area of steep terrain, you will need to increase the Maximum Height Delta and Expected Terrain Slope values to better match the ground in the area. 

For an area that is densely forested, you will want to take a look at your data and make sure that you actually have points present that are from the true ground level. Depending on your dataset you may also be able to use some advanced filtering options from the automatic ground classification dialog to narrow down the points considered when trying to classify ground. 

 

​I know the pole classification, but my project needs to discriminate between medium voltage and low voltage poles. I have a post survey in a shapefile point file, how can I classify a lidar point cloud, from this survey?

If you do not have Medium Voltage and Low Voltage pole classes defined in Global Mapper, open the Filter Lidar tool and right-click on a class to change the class name and color as needed to create your new Medium and Low Voltage pole classifications. 

Before reclassifying your power pole point cloud points into Medium and Low Voltage pole classes, I recommend that you classify the point cloud including generic power pole classification. This will allow you to isolate and work with the generic pole classified points as you work to split them into the Medium and Low Voltage classes. ​​

With poles classified you can use the Filter Lidar tool to hide all points you are not interested in reclassifying, this would be all except the pole classified, Class 15 – Transmission Tower, points. Next, select the points you would like to reclassify as one of your pole subclasses and use the Change Lidar Class tool to reclassify these points. 

  • If your shapefile of vector features contains line features for each pole, you can use the Select Lidar by Distance tool to select the points for reclassification. 
  • If your shapefile of vector features contains area features, select the area features and use the Advanced Selection Option > Select All Point Features within the Selected Area(s) to select the points for reclassification. 
  • Or you can select points manually using the digitizer tool in the 2D map view or the Path Profile view, hold down the control key on your keyboard to select multiple areas of points. 

 

I was playing with the pole feature in a laz trying to get a single point, I think I got that working but then tried to apply it to a tree. I have been getting results showing several points created for a single tree and none are near what I would consider the center of the trunk.

The pole section of the automatic feature extraction tool is designed to extract pole features. In this tool there is a tree extraction section better suited to extract tree features from classified high vegetation points. 

 

Is it possible to create a watershed by clicking a ground point in a point cloud (or a pixel in a DTM)? The point selected should be the lowest point.

You can create and select a point feature representing the lowest point in your study area, and then use the Create Watershed Areas Showing Drainage to Selected Point(s) option in the Watershed Generation tool. This will generate a watershed showing the area that drains to the location of the selected point feature. 

 

Are there suggestions for processing/managing large lidar projects, like an entire US county scale?

To improve the load speed and draw time for a large dataset in Global Mapper, consider creating and loading your data through a map catalog

While there is no file size limit in the Global Mapper program, your computer has a memory capacity that you might reach when processing large datasets. Be sure that your machine is powerful enough to do what you are asking. When processing large datasets you may want to consider breaking the data set up into tiles and processing the data one section at a time. 

 

I want to know how and preferably how to automate the plotting a line to show the path an off contour bank or excavated ditch as it winds across a DEM landscape.  The line would typically have a grade/slope of 1 in 300 in most rural applications although In flatter landscapes 1 in 5,000 may be used. Urban sewers, as I recall, need a minimum of 1 in 50 grade. 

Various design constraints determine the starting point so the line may need to be either rising or falling from that point.

In the field, this is done by arcing a constant distance (radius) from each successive point and finding the desired height RL.

In my CAD program, I initiate a line and manually set each point by using the distance to last point display and mentally interpolating the height between adjacent contours.

I hope you can help.  I’m using Version 11 can v21 produce what I’m after?  

The Adjusting Line Elevations to a Slope function will take a digitized 3D line and adjust the elevations to a user-specified slope. Essentially, if you digitize a line on a DEM, select it with the digitizer tool, right-click and go to Move/Reshape Features, then click Adjust Elevations to a Single Slope, you will essentially be shifting that line to the new vertex elevation values. To visualize a trench, you could create a buffer around a selected line, then use the Calculate Flatten Site Plan option in the right digitizer menu to see the trench dug into the DEM.

 

Is it possible to analyze 3D data in Global Mapper such as Temperature or Salinity measured at different depths in the ocean?

Global Mapper can load and work with 3D data. You can take vector features representing your temperature and salinity readings and style them to create a thematic map. 

Global Mapper can also grid values. Typically this is used for elevation, but you can direct the program to grid values from another attribute by setting the elevation attribute on the Elevations tab of the vector options. Then use the Grid Creation tool to create a 3D raster gridded surface of these values.

 

I’d like to know the best workflow to export a raster file, tilling the image and doing the background transparency.

In any raster format export, you should see a Tiling tab in the Export Options dialog that will allow you to break the data being exported into tiles by one of a few options. 

Common raster formats like ECW, JPEG2000, GeoTIFF, and others can export images and make the background transparent through the use of an additional alpha channel for the image. To enable this option for background transparency, use the checkbox to Make Background (Void) Pixels Transparent in the file Export Options. 

 

How can I sort two shapes files with the same numbers but different positions, into one file of missing points?

In Global Mapper you can search for features with duplicate attribute values. Another option to find features that share some attribute values may be to search the vector features. After searching for features based on a query, you can delete, copy, or further manipulate the found attributes. 

 

How do I perform a complete terrain analysis and what are some lesser known capabilities which can be explored with Global Mapper?

Global Mapper contains many terrain analysis tools for you to use in a complete analysis. These include but are not limited to contour generation, volume measurements, and viewshed creation. Some lesser known tools would be Compare/Combine Terrain layers and Find Ridge Lines. These tools, along with many others, can be found in the Analysis Menu

 

What is the best way to load a subsea pipeline route comprising the end points, intersection points (IP) and the IP radi?

Global Mapper can load and edit vector features. With the points representing the pipeline selected you can use the digitizer right-click option Advanced Feature Creation > Create New Line Feature from Selected Points to connect the points into a line for the pipeline route. 

 

Can you make Global Mapper more compatible with ESRI’s ArcGIS?

Global Mapper supports many different file formats for import and export, and we try to make it as easy as possible to get data into our program. In version 21.0 of Global Mapper the ability to export vector features to a Geodatabase was added to the 64-bit version of the program. The 32-bit version of the Global Mapper can export raster layers to a Geodatabase if you have an ESRI license on the machine. 

You had asked for a general information update. The current release of Global Mapper is version 21.1 which can be downloaded from here. New features and changes to the Global Mapper program can be found in the What’s New section of the Global Mapper knowledge base

 

I would like to know what is the simplest methodology of the webinar.

This Ask the Experts webinar covered many different topics. If you are interested in a particular tool demonstrated in the webinar, you can find details on any function of Global Mapper in the program knowledge base

If you would like to watch the Ask the Experts webinar again, please fill out the form linked here to gain access to the recorded webinars from the GeoTalks Express series. We also have many other recorded webinars and helpful videos openly available for you on our YouTube channel

If you have any questions about the Global Mapper program, let us know in a reply to this email or by contacting our support team (geohelp@bluemarblegeo.com), or our sales team (orders@bluemarblegeo.com).

 

Using BMGC, can you create a local CRS using similarity transformation parameters instead of “fitted” CRS?

In Geographic Calculator you can define a new coordinate reference system and new transformations if you have the information to do so. If you cannot define a new CRS with the information you have, you can use control points to create a best fit coordinate system

 

I want to convert some shapefiles from one CRS to another,  is it possible in your software? Does your software include all the North America’s CRS specifically North Dakota (Williston basin)? Sometimes we use ND83-SF (SPCS North Dakota South / NAD83 / Feet), sometimes UTM83-13 (UTM 13N / NAD83) and in special cases we use SPCS27_250 (SPCS Montana Central / NAD27 / Feet).

These three projections are all supported in Global Mapper. You can select them in Configuration > Projection to reproject your data. 

For the State Plane Coordinate Systems, start by selecting SPCS from the projection dropdown, then select the zone and confirm the datum and units. For the UTM projection, select UTM from the projection dropdown, then the zone and datum. You can also load projection by using the Load from File option in Configuration > Projection and pointing to a *.prj file like the ones you shared.

 

I would like to know, what is the best method to export elevation grids and TIN surfaces into a regular meshes. 3D modeling software prefers this format for visualization and 3D printing purposes. Sometimes working with a triangulated TINN or irregular meshes create problems. If GM has a way to convert/export regular meshes it would be a great tool for 3D modeling, video games, and 3D printing fields.

Global Mapper includes a few different export options for 3D mesh formats. It can export FBX, Wavefront OBJ, just to name a few. I would take a look at this page that would give some more detailed information on the 3D export options: https://www.bluemarblegeo.com/knowledgebase/global-mapper-21-1/Export_3D_Format.htm?

 

I use the lidar module to extract trees on Maine woodlots and would like to hear how the various settings impact results.  Here are screen shots from a recent project where I extracted trees on a 30 acre woodlot.  I experimented with “resolution to extract” and found the .45 feet gave me the greatest number of trees.  Each lot is slightly different in this setting and falls in the range of 0.5 to 0.2 feet.

So, if you could go through the settings in these 2 dialog boxes and explain:  (1) what they do; and (2) how to find the sweet spot.

I’m using lidar data that I either acquire from NOAA or point clouds from maps built from drone acquired photography.

 As you have noted, the settings for classification and extraction will be a bit different for each point cloud depending on the characteristics of that point cloud and the terrain and features it represents. Finding the “sweet spot” for these parameters comes from a bit of trial and error as well as knowing your data and study area. I suggest you first focus on classification and fine tuning those parameters to classify the point cloud correctly before moving onto feature extraction. 

When working with drone image-derived point clouds you will want to make sure you have enough true ground points in vegetated areas to differentiate the ground level fro the vegetation. Since some of the parameters in the non-ground classification and extraction tools refer to height, you need to have ground classified points that can be used to determine the relative height of other points. 

With the Automatic Non-Ground Classification the Minimum Height Above Ground and the Minimum Vegetation distance are the more important parameters for high vegetation classification. The Minimum Height Above Ground sets a threshold for the start of the non-ground classification. This setting helps to week out other ground features like low vegetation, rocks, and cars. The Minimum Vegetation Distance sets a minimum distance between points for an area to be considered vegetation. This is useful as vegetation areas tend to have more spread out points compared to a more solid surface like a building.T he Maximum Co-Planar Distance and Co-Planar Angle Difference apply more to the building classification. Are you seeing your point classified correctly by this tool, or are there sections of points that remain unclassified or misclassified?

When extracting tree features the values you enter for the Minimum Tree Height, and the Maximum and Minimum Tree Spread help to guide the program to break the classified points up into individual tree features. The resolution at which to extract has to do with how finely the point cloud is looked at to extract features. Lower resolution point clouds should use higher values. 

 

I could certainly benefit from seeing a demonstration of the following, starting with a point or polygon “shapefile”:

1) How to embed a system URL pathname into a table field (such as within a shapefile field) to pop up a related Excel file or PDF.

2) How to edit a table value for the URL in case your “client” made a mistake in giving you the URL and now all the pathnames to a pop-up document are “wrong” and need to be fixed//edited.

3) Related Question: Can a shapefile have two table fields (i.e. more than one table field) set up for pop up of 2 separate documents related to one point or polygon?

Thank you for the questions. You can link external files to vector features in Global Mapper using some attributes. You would do this by specifying the path to the desired file to open in a FILE_LNK special attribute.

To add these attributes you can select a feature with the digitizer, right-click, and select Edit to open the Modify Feature Info dialog. Here you can click the button to Add File Link(s). You will then be prompted to select the file you would like to link to this feature. You can link multiple files to a feature. These additional links will be named FILE_LNK_1, FILE_LINK_2, and so on. 

You can also add or edit file links through the attribute editor. Right-click on a layer in the control center and select to Edit Attributes to bring up a table of attributes for the features in the layer. Here you can edit an attribute value by double-clicking on it, or add an attribute. 

To open a linked file, use the Feature Info tool and click on a vector feature. If there are files linked to the feature you will be met with a dialog asking you to select to open the linked file or display the feature attributes.

 

Volume Calculation question. For stockpile calculations in GM, how do you deal with removing conveyors, abutting piles, and other problems in order to obtain as good of data as possible from the point cloud?

Thanks for the question. When using the Pile Volume function in the digitizer, you will want to first constrain the area as best you can to the area you want to calculate. Since this function is used on an elevation grid type of raster, you would want to just digitize an area feature around the boundary of your stockpile to constrain the calculation to a specific pile. 

 

When georeferencing Ground Control Points in the Pixel to Points tool, the cursor “jumps” out of position. Why?

When placing ground control points on your images in the Pixels to Point dialog box, you should not see the cursor jumping out of position. Are you seeing it try and snap to the pixel centers or boundaries in the image? Are you seeing this at all zoom levels or only when zoomed in very closely to the image?

Please try downloading and installing the daily build of Global Mapper and testing your Pixels to Points workflow again. This build contains small updates to the program and will ensure you and I are comparing the same version of Global Mapper. 

Link to download the daily build: https://www.bluemarblegeo.com/products/global-mapper-daily-builds.php

 

When will Excel File data import come?

Currently, Global Mapper cannot import Excel files directly, you must save them as CSV files. There is an open ticket, #GM-4159, on adding the direct import of Excel format files to Global Mapper. Our development team is considering this ticket.

 

And related, is it possible to identify breaklines to constrain the contouring process?

You could use the option in the Analysis menu and go to find Ridgelines, which is currently our closest option. We do have an open enhancement request to automatically extract breaklines from terrain. This is ticket GM-6714. 

 

Is there any option on Global Mapper to draw the shortest path between two points on terrain, maintaining a specific slope cap?

In Global Mapper you can take an existing line feature and adjust the vertex elevations so it matches a user-specified slope. This Adjust Elevation to a Single Slope tool will not alter the x and y positions of the line vertices, but the z, elevation, values will be changed. 

There is a related open feature request on adding the ability to specify a start point, end point, and slope in order to generate a new line feature. This ticket is #GM-2599, and I have added your request for this feature. I will let you know when I hear any updates on this issue. 

 

Can you create a 3d line from x, y, inclination and azimuth?

The COGO digitizer tool in Global Mapper allows you to create a line feature by specifying a start point, bearing, and distance. You can also take an existing 3D line feature and adjust the vertex elevations so it matches a user-specified slope. This Adjust Elevation to a Single Slope tool will not alter the x and y positions of the line vertices, but the z, elevation, values will be changed. 

There is an open feature request on adding the ability to specify a slope value when creating a line feature. 

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