A new large 8 foot color shaded relief map that I have created has been posted for display at a local tourist kiosk in Advocate Harbour, Nova Scotia. Now both tourists and residents of the area will be able to gain a better appreciation of the topography that borders the Northern Bay of Fundy region
Various user manuals that I refer to when working with Leica total stations (Some I created and others from Leica … ).
Geomatics has become a pretty common term in Canada lately and includes many different disciplines such as geographic information systems (GIS), remote sensing, cartography, land surveying, global navigation satellite systems (GNSS), photogrammetry, geography and other related forms of spatial mapping.
Using acronyms and abbreviations is commonly practiced in the Geomatics industry and most of the time people just assume that everybody else knows what every acronyms and abbreviation stands for. Well that is obviously not the case most of the time and over the years I have created myself a little digital cheat-sheet of geomatics acronyms and abbreviations that I use with my work in my writing.
Here is a large collection of common acronyms and abbreviations related to the Canadian Geomatics industry: http://canadiangis.com/geomatics-acronyms-and-abbreviations.php
I created and presented this poster featuring LIDAR Color Shaded Relief model of Bouctouche / Shediac area of New Brunswick at the 2004 Geotech event that was held in Toronto.
Traditional images in geomatics are often two dimensional, meaning that all data in the image can be referenced by X and Y coordinates.
Three dimensional images (3D) incorporate a third dimension (the Z component) which represents the elevation or depth aspect of the data. To incorporate it into an image requires creating special geomatics value added products that allow users to perceive the presence of the third dimension into a traditional two dimensional setting (because most paper and computer screens are flat or two dimensional).
A color shaded relief (CSR) utilizes chromo stereoscopic techniques to help emphasize the depth of the Z dimension from traditional shaded relief models that already portray the presence of an elevation difference. Using carefully edited RGB (red, green, blue) pseudo colors and then encoding them into the shaded relief image provides the user with an even more enhanced feeling that they can perceive a third dimension from a two-dimensional medium (also helping to quickly decipher between high and low elevated regions). When a feature of the same color in the image is shaded darker than the shade of its background, then the background color will predominate in determining its perceived depth position in the image.
There are several different software packages that can be used to create CSR models, but I have found that Geomatica software by PCI Geomatics has proven to produce some of the better results in CSR models generated from DEMs. ChromaDepth 3-D glasses can often be used to further enhance the three dimensional feeling as well. These glasses use sophisticated micro-optics technology to transform color images into stereo 3-D. If you do not currently have PCI Geomatica then you can obtain a trial copy of it from their web site; then follow the steps outlined in the following CSR tutorial.
Here are some more Examples of some of the many color shaded relief (CSR) models that I have created
- Vancouver Island, British Columbia
- Gatineau foot hills of Quebec
- Irvine, California
- Cap Pele, New Brunswick
- Pointe Du Chene, New Brunswick
- Shediac, New Brunswick
- Bouctouche, New-Brunswick
- Makkovik, Labrador (Newfoundland)
- Antigonish, Nova Scotia
Color Shaded Relief related documents:
- Creating a Color Shaded Relief Model from a DEM with PCI Geomatica v9.1 software
- 3D Modeling with High Resolution LIDAR – presented at the GeoTec Conference in Toronto,Ontario and displayed at the Applied Geomatics Research Group in Middleton, Nova Scotia
- Bouctouche, NewBrunswick – Color Shaded Relief – presented at the CCAF annual general meeting held at the University of Moncton in Moncton, New Brunswick, and displayed at the Applied Geomatics Research Group in Middleton, Nova Scotia
- Flood Risk Mapping using LIDAR, SE NB Climate Change Action Fund – presented at Geomatics Atlantic 2004 Conference held at the University of New Brunswick in Fredricton, New Brunswick
- Integration of Digital elevation Models and Imagery : Terrain Analysis of the Antigonish Highlands – presented at the Center of Geographic Sciences in Lawrencetown, Nova Scotia
- Makkovik,Labrador – 3D modeling and Data Integration – presented at the Bedford Institute of Oceanography in Dartmouth, Nova Scotia
- Surface Modeling and LIDAR Validation
- Three Dimensional Flood Modeling with High Resolution LIDAR – (Graduate Project Final Paper) Middleton, Nova Scotia: Applied Geomatics Research Group, Centre
of Geographic Sciences, 200 pages
- Three Dimensional Flood Modeling with High Resolution LIDAR presentation from the Canadian Institute of Geomatics 2005 Conference held in Ottawa,Ontario
A digital elevation model (DEM) or sometimes referred to as a digital terrain model (DTM) is a quantitative representation of the topography of the Earth (or sometimes other surfaces) in a digital format. They are a common component of geographic information systems /remote sensing and are usually represented by cartesian coordinates and numerical descriptions of altitude. In contrast with topographical vector maps, the information is stored in a raster format. That is, the map will normally divide the area into a rectangular grid of cells or pixels and store the elevation of each one as a DN value.
Traditionally most common DEMs used in the Geomatics industry only contain elevation values of the true ground’s surface but DEMs can also sometimes contain other features found upon the ground’s surface as well. When it contains all features it is often referred to as a digital surface (DSM). Digital surface models contain elevation values representing the ground as well as any other objects such as buildings and trees.
The resolution of the DEM, or the distance between adjacent grid points (often the size of the cell or pixel), is a critical parameter in determining the amount of detail that a user should except to represent in the DEM. The smaller the resolution, the more details or features that will be present, e.g. a 1 m resolution DEM will contain more details then a 20 m one and be better suited for hydrological analyses.
DEMs are used as a source of elevation (and to create other digital terrain models) for many different purposes such as:
- to orthorectify imagery
- as a source of topographic information and to create contour lines from
- to identify geological structures in topography
- to identify risk areas and hydrological flow patterns
- to identify flood risk areas
- to determine accessibility
- to identify regions of visibility for radio or cell towers
- to predict how the terrain can effect signal strength and reflection
- and many more uses
Digital elevation models may be prepared in a number of ways, but they are frequently obtained by remote sensing rather than direct survey. Older methods of generating DEMs often involved interpolating digital contour maps from aerial photography produced by direct survey and interpretation of the surface.
Many mapping agencies produce their own DEMs, often of a higher resolution and quality, but frequently these have to be purchased, sometimes at considerable cost. The two methods of creating DEMs that are covered on this web site deal with LIDAR and Photogrammetry methods.
- MacKinnon E (2003) Surface Modeling and LIDAR Validation Middleton, Nova Scotia: Applied Geomatics Research Group, Centre of Geographic Sciences, 49 pages
- MacKinnon E, Sangster F & Hynes D (1999) Makkovik, Labrador – 3D modeling and Data Integration presented at the Bedford Institute of Oceanography in Dartmouth, Nova Scotia
Digital Terrain Modeling is the process of simulating or representing the relief and patterns of a surface with numerical and digital methods. It has always been an integral component to geology related fields such as geomorphology, hydrology, tectonics and oceanography but over the past decade has also become a major component to non geophysical applications such as GIS modeling, surveying and land use planning.
Terrain Models are derived from data represented by digital elevation models (DEMs) and can include shaded relief models, slope and aspect models, perspective scene generation, and drainage basin analysis (and other models).
The following image is a photo representation of a larger poster that I made along with Blair Sangster at COGS in March of 1999.
The project also included a detailed paper and presentation that was presented at the Center of Geographic Sciences Auditorium, in Lawrencetown Nova Scotia.
The project used RADARSAT S2 beam mode SAR imagery and ERDAS Imagine together to provide 3D models representing various geological terrain features.