March 22, 2022

House Site Selection and Visualization with a Variety of Blue Marble Software

Written by: Mackenzie Mills

 

Blue Marble offers two product lines: Global Mapper and Geographic Calculator, and while they each provide a unique collection of tools, there are situations in which their functionality can be applied collectively to address a geospatial challenge.  Within the Global Mapper suite, are the Standard and Pro versions of the desktop software, as well as Global Mapper Mobile, which extends the scope of the software by providing convenient access to data in the field on an Android or iOS device. Geographic Calculator, and its cloud-based sibling, GeoCalc Online, focus on advanced geodesy and coordinate transformation. For projects that require a combination of site visits and data collection, advanced geodetic transformations, and analysis and visualization, multiple Blue Marble programs can be utilized together to help get the job done.

In this scenario, a site analysis for residential construction will be completed beginning with planning and site selection. Ideally, a suitable site would be a relatively flat location that minimizes the required earthworks for digging a basement or setting a concrete pad. The best way to account for all assets of a location and decide on a site may entail a site visit. When going to the property to select where to site the house, Global Mapper Mobile can be used to record points, lines, and areas using GPS-enabled feature creation. The Pro version of Global Mapper Mobile allows an external GPS device and RTK correction to be used for higher accuracy data collection.

A project can begin with data collection in Global Mapper Mobile, or reference data and a Feature Template for data collection can be set up in Global Mapper and shared to the mobile device.

After capturing data representing important features of the property, as well as geotagged photographs of the proposed construction site, the data and images are exported and transferred to a desktop machine running Global Mapper. An important consideration when combining data from different sources, layers may need to be reprojected and transformed to display cohesively in the Global Mapper workspace. Horizontal reprojections are automatically applied on the fly in Global Mapper to match the current display projection. The horizontal projection used for data display and export can be manually set in the Configuration > Projection options. However, for vertical transformation of 3D data and advanced control over horizontal transformations, Geographic Calculator is needed.

Geographic Calculator can be used as a standalone application for many geodetic conversions and transformations, but when installed and licensed alongside Global Mapper, GeoCalc Mode can be enabled to execute advanced transformations within the Global Mapper interface. GeoCalc Mode replaces Global Mapper’s default projection management functionality with a powerful set of geodetic tools based on Geographic Calculator’s geodetic datasource and conversion methods. With GeoCalc Mode enabled, the modified Layer Projection and Configuration > Projection dialogs contain options to select not only the desired coordinate reference systems, but the specific geodetic transformations to use with the loaded data. Reprojection of data is completed by setting the desired projection in Configuration > Projection and exporting the data to a new file.

Using Geographic Calculator’s datasource in conjunction with Global Mapper, GeoCalc Mode allows for more advanced geodetic transformations.

When collecting data in Global Mapper Mobile or with any GPS-enabled device, the data will be collected using geographic (latitude/longitude) coordinates in WGS84 / Ellipsoidal Height. If elevation precision is essential to the project and the collected 3D data is to be combined with data layers using a different vertical system, reprojection using Geographic Calculator or GeoCalc Mode is necessary.

After reprojecting the data collected in Global Mapper Mobile, the features are loaded into Global Mapper and displayed with an elevation layer that utilizes the NAVD88 vertical reference system. Since the collected features and elevation grid are 3D layers, they can be viewed side-by-side in Global Mapper’s 2D and 3D viewers.

Points representing the corners of the desired build site were initially measured and recorded with Global Mapper Mobile, and using the Digitizer tools in Global Mapper desktop, the points are connected to create a polygon. Using this polygon, a Flattened Site Plan is generated in Global Mapper utilizing either the per-vertex elevations of the polygon or an automatically calculated height value that equalizes cut and fill volumes based on the existing terrain. Electing to use the option to equalize cut and fill volume reduces the amount of material that will need to be removed or added to flatten the site.

Global Mapper’s terrain editing tools support grid editing, creation, volume calculation, and much more.

Using Global Mapper Mobile’s data collections capabilities, Geographic Calculator’s advanced coordinate transformations, and the analysis and visualization tools in Global Mapper, a new building site is determined and a plan to flatten the site is created. As the project progresses, Global Mapper Mobile can be used to collect additional field data, such as a survey of the property boundary, and geotagged images of the build process. 

To see Global Mapper, Global Mapper Mobile, and Geographic Calculator working together, check out the latest GeoTalks Express webinar, Planning Engineering Projects using Global Mapper and Geographic Calculator. Register for the webinar here to watch live on March 23, or to view the recorded session.

To use the Blue Marble programs in your own construction planning workflows, download free trials of Global Mapper and Geographic Calculator, and download Global Mapper Mobile for free on the iOS App Store or Google Play Store. If you have any questions, contact us!

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