CoastGIS’99: geomatics and coastal environment
Do you use raster or vector maps - or both? If both, how do you combine them? Would you like to drape some remote sensing imagery (a
raster picture) over the base map(s)/vector data? Vector data (point,
hne and area) is often used for base maps because: (a) it is more flexible,
(b) it is neecled to implement true spatial analysis algorithms in most
GIS toolsets, and (c) it can be scale independent. However, vector data
does not always convey the full message or range of messages suited to
a range of information users, without considerable extra-work needed
to make it more presentable. Raster maps look good, are easier for nonexperts to understand (just like our road maps), have good presentation features (colour, texture, etc.), but are scale dependent. “Zooming”
in or out may be interesting, but image quality degrades and the viewer
may not necessarily be seeing a true representation of the actual scene.
Other problems arise in relation to base maps, vector data sets or raster
images (aerial and satellite imagery). Do you have dissemination rights
to the underlying maps or to the new maps or views created using the
raster data? In the UK, Ordnance Survey's (OS) NetMap is the only OS
data set you can legally use on the Internet and the prices vary considerably depending upon the type of use. Some forms of dissemination
or re-use are contractually prevented.
Analysis of a problem often requires locating and combining maps or
spatial data of quite different types, such as hydrographic maps, nautical charts, land-use maps, vegetation cover imagery, etc. If these are
not already available in digital format, as many will not be, then there
is a digitization procedure to complete before a GIS or other data visualization software can use the data. Even where data is already in digital
format, how does the user determine if it is at the appropriate scale,
with similar and known levels of quality, timeliness, accuracy, precision, etc.?
Don’t forget that “maps” are not the only way to convey spatial information or coastal zone information. New technology offers the possibility to present information using Virtual Reality (VR), 3D representations, animations (2D and 3D) and combinations of maps and images,
video and sound.
GIS as information dissemination/presentation tools
Using GI and GIS via the Web is becoming much more common, with
substantial growth in the number and variety of products available
since they first appeared less than three years ago. However, despite what
the toolsets propose to offer, most current Web-based interactive GI applications are relatively simple m nature, permitting GI data location (from
Web-based metaclata), downloading of small volumes of GI (images
and vector data) and on-line viewing of maps based on simple spatial
queries (such as “where is ‘A’ located?”). There is less practical experience with posing and satisfying more complex spatial queries in a
client/server environment via the Internet or intranets.
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Do you use raster or vector maps - or both? If both, how do you combine them? Would you like to drape some remote sensing imagery (a
raster picture) over the base map(s)/vector data? Vector data (point,
hne and area) is often used for base maps because: (a) it is more flexible,
(b) it is neecled to implement true spatial analysis algorithms in most
GIS toolsets, and (c) it can be scale independent. However, vector data
does not always convey the full message or range of messages suited to
a range of information users, without considerable extra-work needed
to make it more presentable. Raster maps look good, are easier for nonexperts to understand (just like our road maps), have good presentation features (colour, texture, etc.), but are scale dependent. “Zooming”
in or out may be interesting, but image quality degrades and the viewer
may not necessarily be seeing a true representation of the actual scene.
Other problems arise in relation to base maps, vector data sets or raster
images (aerial and satellite imagery). Do you have dissemination rights
to the underlying maps or to the new maps or views created using the
raster data? In the UK, Ordnance Survey's (OS) NetMap is the only OS
data set you can legally use on the Internet and the prices vary considerably depending upon the type of use. Some forms of dissemination
or re-use are contractually prevented.
Analysis of a problem often requires locating and combining maps or
spatial data of quite different types, such as hydrographic maps, nautical charts, land-use maps, vegetation cover imagery, etc. If these are
not already available in digital format, as many will not be, then there
is a digitization procedure to complete before a GIS or other data visualization software can use the data. Even where data is already in digital
format, how does the user determine if it is at the appropriate scale,
with similar and known levels of quality, timeliness, accuracy, precision, etc.?
Don’t forget that “maps” are not the only way to convey spatial information or coastal zone information. New technology offers the possibility to present information using Virtual Reality (VR), 3D representations, animations (2D and 3D) and combinations of maps and images,
video and sound.
GIS as information dissemination/presentation tools
Using GI and GIS via the Web is becoming much more common, with
substantial growth in the number and variety of products available
since they first appeared less than three years ago. However, despite what
the toolsets propose to offer, most current Web-based interactive GI applications are relatively simple m nature, permitting GI data location (from
Web-based metaclata), downloading of small volumes of GI (images
and vector data) and on-line viewing of maps based on simple spatial
queries (such as “where is ‘A’ located?”). There is less practical experience with posing and satisfying more complex spatial queries in a
client/server environment via the Internet or intranets.
32