Big Island Vector data
(roads, rivers, fences, property boundaries, etc.)
- the island has 1400 km of county-maintained road, 46 km unpaved and 1354
km paved, with over 118,000 registered cars
[source]
Road Data - 2003 DLG Notes
- apparently in 1995, many or all of the transportation DLGs were re-done
by the USGS
- the differences from the previous version (1981 map production) is major
- there is a huge number of new roads and cleaned up topology - but there
are also hundreds of dirt roads missing, which were present in the 1981 data
- the USGS now provides both the old and new (1981/1995) datasets in SDTS,
and the higher file number is the newer file (e.g. 852225 vs. 1384033)
Road Data - 1997 DLG Notes
-
free
DLG-O data for the island is available
- in 30-minute by 1-degree regions, each split into 8 15-minute regions
- file names H73, H82, H91, H92, H93, H94, HZ1
- all but the western tip of the island is in UTM zone 5
- problems with the free data
- lots of roads are missing
- roads have lot of bogus "crooks" and angles
- 7.5-minute DLG files are also available from the USGS ESIC
- 81 files to cover the island, cost around $600, now much cheaper due
to price reductions
- ordered and received in 1997 - it's much cleaner,
more complete and accurate
-
free, 30-minute DLG
|
cheap, 7.5-minute DLG
|
- even with UTM, there's a
datum issue - the DLGs
claim to be NAD27 (although they are actually OHD, Old Hawaiian Datum), the 30m
DEMs are Old Hawaiian Datum, and the 10m DEMs are NAD83
Road Geometry
- Highway markings
- center of road always indicates passing status
- three kinds of reflectors
- older, less-maintained roads usually have only a single dashed line
in the center, with no edge markings
- Road signs
- elevation signs are at each 500m contour boundary on major highways
- highways have number signs
Fences
- in pasture / rangeland, there is always fence on both sides of the road
- posts are either metal rebar or wooden beams
- dimensions: around 1.2m tall, 2.5m spacing
- 3 to 5 wires, 25-30cm apart
- top wire is 10cm below top of post
Water Vectors
- as the DLG show, there are virtually no lakes or ponds; only a few artificial
reservoirs
- streams appear only where the land is old and the rainfall is high, and
most of them are only temporary, during rainfall
older Tax Map info...
- As of 1998, County of Hawai‘i tax maps are reportedly still maintained with
ink on linen.. some of the maps now online have date stamps
which imply they were last updated in 1984 (!) Printouts are available in some local public libraries.
- 4/99 Called the County Planning Office and learned there was
an electronic version of the real estate information made in the 1990s
- the company is First American Real
Estate Solutions
- the county provides the paper documents to the company, the company
scans them and re-sells them, by county, on CDROM, along with a Windows-based
program for viewing and searching the information
- cost is around $1000 per county, with "assessor maps" costing around
$300 more
- the fee is annual; information is updated each year
- however, the "assessor maps" are just raster scans, there is no boundary
vector data or geographical coordinates
- also available was georeferenced by
LandInfo Parcel Tax Maps
- are available as 300 dpi TIFF files
- includes individual tax identification numbers, acreage, street names,
and other features
- they are sold for $5/map, which is $32,345 for all 6,482 maps in Hawai‘i
County
- georeferenced!!
- unfortunately you must buy the entire county