Insights Into Remote Site Conditions Without Leaving Your Desk


Engineering · Construction · Law · Development · Everybody

Gain Insights Into Remote Site Conditions Without Leaving Your Desk: Industry trends, tips, and practical uses for aerial imagery and geographic data from First Base Solutions, the experts who brought you MapWarehouse.

Wednesday, January 27, 2016

All About Custom Mapping & Terrain Models

Taking flat images to new heights


About


Where the most current mapping data possible is required for site development, asset inventories, or land use planning, First Base Solutions is well equipped to undertake complex, highly detailed custom mapping of your site. We offer full service map production beginning with acquiring custom aerial imagery from our own aircraft to ensure the features in the final mapping are up to date and at the level of detail you need. We delineate the ground feature types you request, and even produce 3D digital models of the terrain. All this comes at a fraction of the price of labour-intensive field surveys and traditional mapping methods.

What is it?


Custom photogrammetric mapping is a specialized service offered by First Base Solutions where the ground features you’re most interested in can be delineated from aerial photos and delivered in your choice of GIS or CAD formats. Where extremely up to date mapping is needed but no imagery or suitable base mapping exists already, we will also fly your area and acquire new aerial imagery just for your project in order to create your map.

Our signature service is topographic mapping, where we can produce highly detailed elevation, terrain, or surface models of the landscape from controlled stereo model data sets, but we are frequently called upon to produce maps of roads, drainage features, building footprints, utility infrastructure, floodplains, and other above ground build structures and natural features as well. While most mapping begins with aerial or satellite images that we acquire, we can perform a similar service to digitize features from paper base maps and historical data sources, align, retrofit, and perform file format conversion on existing spatial data sets to meet today’s standards, or any combination of these services.

Topographic Mapping - DSM vs. DEM. vs. DTM


DSM, DEM, and DTM are all different ways of visualizing three dimensional relief of the landscape. All begin with overlapping aerial photos which can be viewed in stereo as 3D images by our photogrammetrists. A regular grid of points, called spot heights, is superimposed on the images where elevations are measured and recorded. The spot elevations can then be interpolated to form a surface which can be used to overlay a wide variety of GIS and CAD data.

A digital surface model (DSM) is a topographic elevation model of the Earth’s surface including every natural and artificial feature. DSM forms the basis for creating true orthophoto production.

A digital elevation model (DEM) is similar, but includes only bare earth features without vegetation or structures.The DEM data is used to create a terrain surface, terrain orthorectification and to generate contour lines.

A digital terrain model (DTM) takes the DEM a step further, and uses break lines in addition to spot heights to refine the model. The breaks are identified from our orthophoto and delineated along terrain impacting features such as ridges, valleys, watercourses, road edges and structures. When the spot heights are interpolated to create the terrain model or contour lines, the terrain disruptions at the break lines are taken into account to produce a more true to life representation of the surface.

First Base Solutions has an inventory of DTM as spot heights and break lines from our 2002 orthophoto that has been divided into tiles and is provided in DWG format with 3D polylines. The capture of the topographic model of the surface includes elevations on a 40 m to 50 m grid spacing with an accuracy of +/- 40 cm. Break lines were added along visible terrain impacting features such as the edge of roads, drainage and center line of railways. These elevation models are available through MapWarehouse covering the greater Toronto area and Simcoe Kawartha Regions. Contour lines at 1 m intervals are available for the same coverage in DGN format for MicroStation. Custom elevation models can be created for your project based on newer or custom acquired photo at intervals up to 1/2m.

What’s it for?


Custom mapping is useful in many industries. Our extremely high resolution photo allow us to map even very small ground features with exceptional detail. In photos with 3 cm resolution, ground features less than a square foot such as utility poles can easily be accurately positioned and delineated. The elevation models we produce from the photo are ideal for analyzing surface water drainage patterns and sight lines, important aspects of many site plan designs and other engineering projects.

Together, the aerial photo, elevation model, and ground feature mapping form a base map to hold your company’s spatial data inventory. Our GIS Mapping Group utilizes "Soft Copy" Photogrammetry, a technology that allows the integration of vectors and imagery in a 3D view. The base map is an excellent starting point for implementing an automated "Land Information System" for our clients, and to incorporate customized mapping by-products for use in related projects down the road. This starting point provides the perfect solution where an update or revision of an existing vector base is required, or for the creation of additional or new data.

We not only integrate your existing data, we can even improve on it in. Parcel fabric mapping, for example, which was traditionally maintained by countless organizations using different methodologies can have the geometry retrofit to align with better quality data we provide while maintaining the original tabular attribute information associated with each parcel. First Base Solutions also has aircraft and aerial camera systems at our disposal, when combined with field topographic surveys from our parent company, J.D. Barnes, can be used for highly accurate precision mapping suitable for even the most detailed engineering work.

Who’s it for?


First Base Solutions caters to both private and public sectors customers involved in planning, design, and the management of land related activities. Industries we regularly serve involve planners, engineers, and all levels of government, particularly organizations with extensive portfolios of infrastructure and other assets which are geographically disbursed like roads or utilities. Our clientele includes companies or organizations who are new to digital mapping technology and need a solution built from the ground up, and those who already have established GIS or CAD mapping departments and just need a hand upgrading their data resources.

Features and benefits?


Since we are able to coordinate our mapping services with photo control points provided by our surveyor partner, J.D. Barnes, accuracy is one feature that sets our mapping services apart. As we produce custom vector layers, we can ensure the mapped location of any feature will be no more than 1.5x the photo resolution in the horizontal plane and 2x the photo resolution in the vertical plane from the true ground location. This means, when we place spot heights to create an elevation surface prepared from 3 cm resolution photo, for example, the x,y placement of the point will be no more than 4.5cm from it’s true ground location and no more than 6 cm out from the true elevation.

Mapping from the ground can be a time consuming, labour intensive, and expensive undertaking. These problems delay access to information critical to making sound decisions. Beyond timing and budget concerns, managers must also consider health and safety concerns when workers will be dispatched to map areas with busy roads, water features, or steep and treacherous terrain. Taking advantage of First Base Solutions’ aerial mapping services can help mitigate these risks or avoid them altogether.

  • Horizontal accuracy 1.5x the photo resolution
  • Vertical accuracy 2x the photo resolution
  • Deliverable in any CAD and GIS format
  • Format conversion, datum translation and reprojection services
  • Geometry retrofitting and data massage services
  • Considerable cost and time savings over traditional mapping methods
  • Risk mitigation - no need to visit hazardous sites as with ground survey mapping
  • Custom and archived mapping available - one stop shopping
  • Integrates with existing and future mapping data sets 

First Base Solutions Advantage?


Part of the reason First Base Solutions can supply mapping with such incredible accuracy is our relationship with our parent company, J.D. Barnes. We often work and provide services in conjunction with this surveyor on large mapping projects. The ground control points they provide allow First Base Solutions to develop custom mapping with positional accuracy far superior to mapping companies who don’t have the benefit of a similar partnership. We are, in fact, the only aerial mapping company in Canada to have such close relationship with a traditional survey company.

Pricing?


There is no preset cost for any particular service. Each job is unique and will be quoted individually based on a few different criteria. In general, the same factors that affect the overall price are also linked to the turnaround time for completion and delivery.

1. Is photo already available?
We may already have recent orthophoto covering your site at a resolution that would produce the contour intervals or detail level you would like. In this case, there would be no need to fly the area specifically for your project. If flying is required to take new photo or satellite imagery needs to be acquired, the price of this preliminary service would be included in your quote.

2. The size of the area
Naturally, the larger the area, the more work to be performed. Labour expenses will generally correspond with the amount of mapping ordered.

3. Accuracy requirements
The more detail that is expected in the deliverables will also translate into added labour.

4. Site specific ground cover and complexity
Complex urban landscapes have unique challenges not faced when mapping rural areas. Compact urban areas typically have far more detail to sort out than similar sized areas of farmland. Heavily forested areas can pose challenges as well because parts of the ground may be obscured in the photo and require additional research.

5. Season
Like any business, First Base Solutions has a busy season and a low season which will affect our availability. Some mapping ought to be completed only using “leaf-off” imagery, which means waiting until early Spring or late Fall to fly if new imagery is needed. The mapping department is often occupied processing imagery immediately following the flying season.

How to Order?


Each year, First Base Solutions adds to our extensive library of aerial imagery and related mapping dating from 2000 to present. The archived maps are divided into 500m x500m tiles and made available for download in a variety of CAD and GIS formats through our MapWarehouse e-commerce site.

To order new, project specific mapping, simply call or email us with a few details about the coverage area and type of mapping you have in mind, and what you plan to use the mapping for. We can make recommendations and prepare a quote for our services for you to review, sign, and return.

Alternatively, we frequently bid on jobs through the Request for Proposals process. Forward a copy of your RFP to us and we will gladly reply with a detailed plan describing how we can fulfill your requirements.