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Advocate Harbour Color Shaded Relief Map

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

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 (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.

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

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

Orthophoto & LIDAR CSR for New Brunswick

Color Shaded Relief related documents:

 

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:

 

 

Digital Terrain Modeling

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).

Script to generate a PIX file large enough to contain all input DEM files

Below is a simple EASI script used with the MODEL command in PCI will generate an output PIX file with extents large enough to contain all of the input files PIX files and then mosaic each of the input files into the output pix file. It was designed to mosaic several DEM files into one large DEM file.

This was originally created for PCI Geomatica v9.1 but was last tested and working with no problems in PCI Geomatica v10.0 – Just copy the code below into a blank text file and edit as needed.

!—————————————————————————-

! Multiple DEM Mosaic Script
! [mul_DEM_mosaic.eas]

! Ted MacKinnon – tmackinnon.com
!
! This script will generate an output PIX file with extents large enough
! to contain all of the input files and then mosaic each of the input
! files into the new output pix file.
!
! This script was designed to mosaic several DEM files into one large
! DEM file. Each input DEM file must have the same projection,
! resolution and at each DEM should have at least 150m overlap.
!
! The user is expected that the user will enter (or verify) the parameters
! of ‘CIMPRO’ at the bottom of this script prior to running the script.
! Parmaters such as BXPXSZ and DBIC have been hard coded.

!—————————————————————————-
!—————————
! Define variables
!—————————

!for input & output pix files and pixel size

local string inputFile, outputFile
local string pixel

!to obtain list of input files
local mstring inputList
local integer inputIndex

!for extracting georeferencing information

local GeoInfo geoInfo
local integer geoFile

!to contain bounding rectangle of all input files

local double boundULX, boundULY, boundLRX, boundLRY

!—————————————————————————-
! Clear the EASI window and then show the header information
!—————————————————————————-

PRINT @(1 ,1,CLREOS)

print “———————————————————————–

print @reverse,” ‘Mosaic multiple DEM files’ EASI Script “,@alloff
print “”
print “”
print “”
print “———————————————————————–“
print “”
print ” This script will generate an new output PIX file with extents large “
print ” enough to contain all of the PIX files in this directory and then “
print ” mosaic each of the PIX files into the new output file.”
print “”
print ” The output file will contain the following projection: “
print “”

! The projection will be printed to the screen as a general reminder

print ” UTM 11 S E000″

print “”
print “———————————————————————–“
print “”

!—————————————————————————-
! Collect input from user
!—————————————————————————-

print “”
print “Enter the Output file name:”
input “>” outputFile
print “”

print “Enter the pixel size for: “,outputfile

input “>” pixel

print “”
print “”

PRINT @(1 ,1,CLREOS)

!—————————————————————————-
! Create list of input files
!—————————————————————————-

sys “dir *.pix /b > pixlist.txt”

inputList = Text$Import(“pixlist.txt”)

!—————————————————————————
! Read georeferencing of each input file
!—————————————————————————-

for inputIndex = 1 to F$LEN(inputList)

print inputList(inputIndex)

geoFile = DBOpen(inputList(inputIndex), “r”)
call DBReadGeoInfo(geoFile, geoInfo)
call DBClose(geoFile)

print “Georeferencing: “, geoInfo.Units
print “Image extents: “,geoInfo.ULX, “, “, geoInfo.ULY, ” “, geoInfo.LRX, “, “, geoInfo.LRY

PRINT @(1 ,1,CLREOS)

!————————————————————————-
! initialize bounds using first file
!————————————————————————-

if inputIndex = 1 then

boundULX = geoInfo.ULX
boundULY = geoInfo.ULY
boundLRX = geoInfo.LRX
boundLRY = geoInfo.LRY

else

!———————————————————————–
! assumes UTM projection (ULY > LRY)
!———————————————————————–

if geoInfo.ULX < boundULX then
boundULX = geoInfo.ULX

endif

if geoInfo.ULY > boundULY then

boundULY = geoInfo.ULY

endif

if geoInfo.LRX > boundLRX then

boundLRX = geoInfo.LRX

endif

if geoInfo.LRY < boundLRY then
boundLRY = geoInfo.LRY

endif

endif

print “”

endfor

print outputFile, ” file extents: “, boundULX, ” “, boundULY, ” “, boundLRX, ” “, boundLRY

!—————————————————————————-
! create the output PIX file containing bounds
!—————————————————————————-

FILE = outputFile
TEX1 =

!Specify the # of channels here

DBNC = 1,0,0,0
DBLAYOUT = “PIXEL”

!Specify the projection info here

PROJECT = “UTM”
ZONE = 11
ROW = “S”
ELLIPS = “0”
LLBOUND = “N”

ULX = F$STRING(boundULX)
ULY = F$STRING(boundULY)
LRX = F$STRING(boundLRX)
LRY = F$STRING(boundLRY)
BXPXSZ = pixel
BYPXSZ = pixel
REPORT = “TERM”

run CIMPRO

!—————————————————————————-
! Mosaic each PIX file from the listing into the outputfile
!—————————————————————————-

inputList = Text$Import(“pixlist.txt”)

for inputIndex = 1 to F$LEN(inputList)

inputFile = inputList(inputIndex)

!————————————————————————–
! Clear the EASI window and show progress
!————————————————————————–

PRINT @(1 ,1,CLREOS)

print “”
print “Mosaicking “, inputFile, ” into “, outputFile
print “”

FILI = inputFile
DBIC = 1
DBVS =
DBLUT =
FILO = outputFile
DBOC = 1
BLEND =
BACKVAL = 0

run MOSAIC

endfor
!—————————————————————————-
!—————————————————————————-

Color Shaded Relief Model of Vancouver Island

Color Shaded Relief Model of Vancouver Island, British Columbia

The above image is a Color shaded relief (CSR) model created using a DEM of Vancouver Island, British Columbia using PCI Geomatica software. The change in relief ranges from 0 m (blue) up to over 2200 m (red colors). Vancouver Island is a large island in the province of British Columbia off the Pacific coast of Canada, it is the largest island (32,134 square kilometers) on the western side of both North and South America.

This image has been published in various books, University Course material (such as UVic) and papers such as the Vancouver Sun & the Montreal Gazette

More examples of Color shaded relief (CSR) models …

Color Shaded Relief Models – Pointe Du Chene, New Brunswick

Color Shaded Relief Models of Pointe Du Chene, New BrunswickColor Shaded Relief Models of Pointe Du Chene, New Brunswick with flood
The above two images were created for my LIDAR flood modeling graduate research project. The first image is before the flood scenario; featuring a color shaded relief perspective view pointing south east from the Northumberland Strait landwards across the Pointe Du Chene wharf. The second image is of the same color shaded relief perspective view but features a 2.55 m flood level super imposed on top of it.

The 2.55 m flood level was an actual recorded storm surge water level that effected this area during a winter storm on January 2001. The two images below show the same flood level and area but from an overhead aerial view. The first image is with an orthophoto and the second image is with the color shaded relief.

Pointe Du Chene, New Brunswick with floodPointe Du Chene, New Brunswick with flood

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