GIS data files

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GIS data files

• GIS data layers are available from a variety of
  sources, generated mostly by digitizing of maps,
  or onscreen from photography.
• (Scanned maps are only useful as backdrop for
  digitizing)
• Special themes you just need to know who to
  contact
• General topographic data varies by country and
  province / region
• Scales of data
• In general smaller scale data are freely
  downloadable
• Medium-large scale costs money or needs
  arrangement
• Local (e.g. city) only by special arrangement
• Should all data collected at taxpayers expense
  be free ?
• There has been a general move towards making data
  available, especially this millennium

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GIS data Global (small scale)

The largest mapped scale for the whole world
covered is 11,000,000. Created by digitizing the
International Map of the World (IMW) The
Digital Chart of the World (DCW) was completed in
1992 Free download, but is not suitable for
larger scale mapping. IMW example
http//www.etopo.ca/e5001.html
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Federal National Topographic DataBase created
by digitizing National Topographic Series maps
Topographic map data are available in digital
form 1250,000 all of Canada 150,000 all
the provinces, parts of the Territories Since
2007, download data  http//www.geogratis.ca
NTS grid by province http//www.mapconnection.
com/topoindex.html National Atlas of Canada
http//atlas.nrcan.gc.ca/site/english/maps/topo/ma
p
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One 1250,000 map sheet contains 100 x
120,000 Each 1250 000 is 1 degree latitude by
2 degrees longitude.  Each 120 000 TRIM sheet
is 6 latitude by 12 longitude. Total map
tiles 7027
Provincial (BC) GIS data
The province was digitally mapped at 120,000
from aerial photos taken in 1980s completed 1996
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BC 'TRIM' digital mapping(Terrain Resource
Inventory Management)
TRIM I  data consisted of five sets of layers
a. Contours (lines for cartographic depiction).
b. DEM (for 'analysis and hill-shading). c.
Planimetric (points and lines, e.g. roads,
rivers, buildings, etc). d. Text - annotation
e. Control points (for photo correction)
These form the basis for GIS in BC, the best
provincial data but a. The data are
planimetrically correct but with few
attributes b. There was limited ground checking
c. By completion (1996), data were 7-15 years
old .. Also at first tricky for many users to
import before FME http//www.safe.com/pro
ducts/desktop/formats/index.php
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TRIM raster image from lrdw.ca (scan)
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TRIM II 1997- ?

• Need for updating
• More detail photos 140,000 v 170,000 for TRIM
  I
• Add orthophoto layer
• Specs and more details
• http//ilmbwww.gov.bc.ca/bmgs/pba/trim/
• About 70 complete
• Progress http//ilmbwww.gov.bc.ca/bmgs/pba/trim/i
  nspprod/inspprog.htm

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TRIM II coverage, showing areas with orthophotos
(from lrdw.ca imap)
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BC Land and Resource Data Warehouse
Download data from www.lrdw.ca topographic
others Vegetation Resource Inventory by 120,000
tiles BEC zones http//www.for.gov.bc.ca/hre/becw
eb/resources/maps/gis_products.html
Other parts of Canada NWT http//maps.gnwtgeomat
ics.nt.ca/portal/index.jsp Yukon
http//geomaticsyukon.ca/ Manitoba
https//mli2.gov.mb.ca/ PEI http//www.gov.pe.ca/
gis/index.php3?number77868 120,000 data BC,
AB, MB, Maritimes, southern ON/QC 150,000
(NTDB) for the rest SK, NL, northern ON/QC
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Some other types of data
Municipal areas data can be viewed but not
usually downloaded e.g. pgmap www.mapplace.ca
Other data and map links Canada thematic
(census) data Thematic data are acquired from
Statistics Canada. Universities take advantage
of the 2001 Data Liberation Initiative
http//www.statscan.ca/english/Dli/dli.htm These
data are available through the UNBC spatial data
librarian. Satellite (raster) imagery can be
downloaded from many sites .. e.g. geobase.ca
see GEOG432 Data download websites e.g.
http//www.mapcruzin.com/
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Assembling data

• View BC data at www.mapplace.ca and www.lrdw.ca
  - imap
• Data appears as a multiscale Seamless
  dataset
• Downloaded data are by map tile / sheet
• Desired area will need multiple (parts of) sheets
• Steps after download
• Merge
• Dissolve
• Clip

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merge
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dissolve
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clip
Software enables a batch clip for all designated
layers
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Clipping for lines and points