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Canadian GIS and Geomatics

Often we are supplied with coordinates in decimal degrees but need to use Degrees, Minutes, and Seconds instead. Luckily, there are several solutions that you can use, here is a simple coordinate converter tool that I use.

Geomatics Acronyms and Abbreviations

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

Geomatics – GIS data base modeling

The design of the spatial database is the formal process of analyzing facts about the real world into a structured model. Database design is characterized by the following phases: requirement analysis, logical design and physical design. In more common terms, you basically need a plan, a design layout and then the data to complete the process.

Geomatics – GIS Spatial Modeling

GIS Model of Average Annual Precipitation of the Annapolis Valley, Nova Scotia

GIS Spatial Modeling is the process of modeling, examining, and interpreting geographic data.It uses a set of defined methodology and analytical procedures to derive information with spatial relationships between geographic phenomena. It can be useful for evaluating suitability and capability, for estimating and predicting, and for interpreting and understanding real world situations. There are four traditional types: spatial overlay surface analysis, linear analysis, and raster analysis.

Data with spatial relationships can be modeled in a GIS to provide images and relationships that can be interpreted to help solve problems and provide information in a way that data bases by them selves can not. The image to the right for example is a screen capture of a GIS thematic spatial model created from a database of precipitation measurements from various weather stations and data loggers spread out across the region. ESRI Geostatistical Analyst was used to create a model that can be easily used to depict the amount of precipitation that a community in the region would experience based on the data from the databases.

Spatial Modeling Examples

Below are two presentations that I gave on GIS Spatial Modeling, one is an informal more information based one that was used to train other students how to use the ESRI Geostatistical Analyst extension and the other is a more formal presentation that was open to all students and faculty at the campus.

CanadianGIS

CanadianGIS.com is an extension of my web site that I started back in 2005 after I noticed that there was a real need to have somewhere on the web to help find Canadian GIS resources. And although there were a few other websites starting around that time related to GIS, nobody else was really dedicating a site to Canadian GIS topics.

CanadianGIS.com logoThe site has evolved slightly since then with a few functions or sections being added to it or removed as time went on but it has always been primarily used to promote the Canadian GIS & Geomatics Industry and to share information with other Canadians that also have an interest in GIS. It also went well together with GISjobs.ca, another GIS site that I created to help Geomatics students find Canadian GIS & Geomatics related jobs much easier. GISjobs.ca turned out to be a real success and eventually led to the creation of GoGeomatics, another Canadian Geomatics job board site that allowed people to post GIS jobs for free (now is fully fee based).

CanadianGIS.com helps provide people with resources about Canadian GIS & Geomatics related data, basic information about Canadian companies that provide geomatics services, locations of Canadian data and maps, information about GIS conference & events, places to find Canadian GIS employment and education info and many other great resources. Content for the site been created by me and a few volunteers, with some also being supplied by various GIS companies and academic institutions.

If you have not yet checked the site out then I encourage you to go and see for your self, and if you discover that there is information related to Canadian GIS resources that I have missed then please do let me know. – Join the Canadian GIS LinkedIn Group (2200+ members) or the Canadian GIS FaceBook Group (2100+ members but mostly different from the LinkedIn group)

regards,

Ted MacKinnon -Geomatics Specialist

tmackinnon.com

Contact Me: email

Twitter: @tedmackinnon or @CanadianGIS

LinkedIn: tedmackinnon

FaceBook: ted.mackinnon

[page originally published in Jan. 2009]

Digital Elevation Models (DEMS)

Digital elevation model (DEM) of Lismore, Nova Scotia

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.

 

Digital Terrain Modeling – Color Shaded Relief Models

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 color shaded relief (CSR) perspective view of high resolution LIDAR

Three dimensional images (3-D) 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.

Many different software packages can be used to create CSR models, but PCI Geomatica has been 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.

Color shaded reliefs utilize chromo stereoscopic techniques to help emphasize the depth of the Z dimension from traditional DEMs

Below are link to pages that contain several examples of Color shaded relief models that I have created for various projects and clients. PCI Geomatica has been 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 software then you can obtain a trial copy of it from their web site; then follow thesteps outlined in the following CSR tutorial, you can also use ArcGIS and other GIS software as well.

A perspective view with a color shaded relief model

Color Shaded Relief related:

 

 

Geographic Information Systems (GIS)

Geographic information systems commonly known as GIS has become a rapidly growing technological field that allows Geomatics Specialists to solve and model real world situations by incorporating digital spatial and associated tabular data. It is often defined as a comprehensive computerized information system made up of hardware, specialized software, spatial data and people to help manipulate, analyze and present the information used for storing, manipulating and analyzing spatially indexed information.

Geographic Information SystemsGIS operates on many levels and over the past decade has become an essential tool for most urban and resource planning and management organizations. On the most basic level, GIS can be used for simple digital cartography, to create various types of maps.

However the real power of GIS is through its abilities to use both spatial and statistical methods to analyze attribute and geographic information together. The end result of such an analysis can be vast amounts of derivative information, interpolated information or prioritized information.
Geographic information systems commonly known as GIS has become a rapidly growing technological field that allows
Geomatics Specialists to solve and model real world situations by incorporating digital spatial and associated tabular data. It is often defined as a comprehensive computerized information system made up of hardware, specialized software, spatial data and people to help manipulate, analyze and present the information used for storing, manipulating and analyzing spatially indexed information.

GIS technology can be used for scientific investigations, resource and utilities management, modeling, assessments, development planning, cartography and route planning and many other applications.. Some of these and other aspects of the GIS field are currently covered on this web site including projects related to spatial database modeling, Geostatistical spatial modeling, mobile mapping, cartography, and interactive web mapping.

Below are some examples of GIS from a few of the many GIS based projects that I have been involved with over the past few years. The links are to PDF versions of papers, presentations and or manuals related to GIS, I have many more, if anybody is interested in a particular topic then feel free to let me know, as I may have a document available related to that topic.

Examples of GIS

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