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Photomaps
We know how important it is for natural resource professionals to work with accurate maps. Our photo-map product can become a powerful tool for your business. Shown below is just a simple illustration of our capabilities. This example consists of an aerial photo that was overlaid and adjusted to fit under a 1:20,000 scale forest inventory map. Other descriptive information can also be added to these photo-maps, such as complete stand information and geographic names (lake names, river names). Such maps can have wide applicability in the area of field navigation, compliance monitoring, map updating, etc. Details such as rock outcrops, small swamps, tree clumps, etc. that are never evident on other paper maps are now readily visible. Orientation can be achieved with much improved accuracy. Having this level of detail in your hands would tremendously help your navigation and mapping tasks, such as boundary location and road location. When other features such as reserve boundaries are added to the map, there can be little argument as to their precise location - a powerful tool for compliance monitoring. Examples:
top left:
raw aerial photo incorporated into GIS, corresponding shapefile overtop.
Once we have accurately georeferenced
the images to the vector files, we can mosaic two, or more, corresponding
images together to create large scale photomaps (seen below). The
seam connecting the two images is barely visible as it runs through the
lake. Each photomap has had the topographic displacement (hills and
valleys) mathematically removed or stretched to match the map/shapefile.
Some companies may try to sell you on simple image registration but don't
be fooled, image registration will not fully remove topographic displacement
and will result in areas of high error. Only true image registration, rectification
and warping will result in precision mapping.
Pictured below is an excellent example of shapefile data that was created by a third party client. Through image rectification we were able to identify several areas reaching errors of up to 50 meters!! Obviously this degree of error is unacceptable and tends to defeat the entire purpose of a GIS. Examine the photomap and see the errors between the digitized shapefile and the delineated aerial photo.
Using a combination of differentially
corrected ground control points, identifiable features on the photos, and
natural features, we can reliably and accurately identify areas of high
error and correct the mapped data, thereby maintaining the spatial integrity
of your database.
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Send
mail to borealis.forestry@onlink.net
with questions or comments about this web site.
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