Cartography Survey Equipment / GPS System Updated Proposal
Overview
The OCF Cartography Crew is chartered with creating and maintaining accurate
maps of the Fair property, for various uses. These include event maps for use by the
Fair-going public, operational maps for use by Fair staff during the event, and
reference maps used by Fair management for various administrative purposes.
These maps include, by necessity, both natural and manmade features, in order to
tell an accurate and complete story of the Fair’s spatial environment.
The Fair site is a dynamic environment, shaped and changed year over year by the
hands and feet of our community, as well as by the slow, persistent evolution of the
natural environment, as the river migrates and the canopy grows and shifts. As the
Fair has aged, our maps have evolved, updated from time to time via various means
and successive generations of OCF cartographers.
As our crew has evolved, we have attracted volunteers with professional GIS backgrounds, and now have the specialized skills within our Fair crew necessary to
employ professional-grade survey equipment in order to update the Fair’s catalog of
maps. The intention of this project is to outfit our crew with a set of equipment
capable of surveying various Fair features to a level of accuracy sufficient for ourmapping purposes.
Equipment use plan and benefit to the Fair
The Cartography Crew has an established backlog of mapping requests, sourced
from management and various crew coordinators, and plan to utilize the equipment
purchased and volunteer staff time to perform the surveys necessary to support
these requests.
The types of data to be gathered and updated using this equipment include:
- Fair utilities, including water lines, communication lines, and other infrastructure
- Camping areas
- Path contours
- Parking lots
- Booth locations
- Fencing, roads, and area boundaries
- Stages and other built features of the Fair
We expect this work to be completed over several years, which may suggest that
this request be categorized as a long-term capital project.
Considerations and Trade-offs
The driving goal of this system is to make it useful to as many crews as possible. For example, even though we currently do have some GIS layers for Water, IT, and Recycling, Camping crew can't participate because the current accuracy is only within about 20 feet, and they need it down to about 1 foot or less.
GPS systems work by triangulating distances from satellites and sometimes ground based stations. The more satellites or stations you have the more accurate your fix (point) is. The USA put up the first set of GPS satellites in the 70s, but other countries eventually followed suit. Collectively these comprise the Global Navigation Satellite System or GNSS. Modern day receivers are built to take advantage of everyone's satellites and hence can achieve more accurate fixes on the order of a few meters of uncertainty around where you're standing. Over time several GNSS augmentation systems have evolved that can reduce the fix uncertainty down more, and more until at today's state of the art, we can get it down to about 2 centimeters or an inch around the point your trying to measure. That technology is called Real-time kinematic (RTK) GPS which is a form of Differential GPS.
RTK GPS requires three things; A fixed GPS station at a precisely known point; a roving GPS station to survey new points; and a way to send correction data from the fixed station to the rover. One of the choices the fair needs to make is, should we just use our own radios to send this data, or should we subscribe to a Cellular data service like T-Mobile to help us cover more area? From several conversations we seem to be leaning toward the former.
The fixed reference station also needs AC power, and an unobstructed view of the sky, which are hard to come by at the fair.
It doesn't have to be that close to the area we are surveying, up to 10km away is fine. Here is a short list of our top choices for the reference station location:
- The Tickets West pole next to Peach Power
- Over at the Winery
- The Dodeca Art Center
- The Hub communications tower
Our first choice is the Tickets west pole, which is also the closet to our survey area. However because it's in a low flood plane, sending the correction data from there won't work very well. Our plan is actually to ship it over our wired LAN up to the Hub tower and send it from there. Since the pole is rather short, we will have to add an extension so that the antenna is slightly above the height of the Tickets West tent, and any other nearby obstructions. This will require a sub-project to upgrade the LAN infrastructure, and the height of the Tickets West Pole. See:
Peach_Power_Network_Upgrade.
Worksheets
These are here to help us understand what
might go into a project, like a bill of materials. Some are here for reference only, and do not contribute to the total. The rows with zero quantity are alternative sources or versions of a part. This makes life easy if the primary source is out of stock, or we need to adjust some aspect of a project.
The best way to read this proposal is to start at the "
Totals" section, and follow the links for each line item back up to the worksheets to see where their subtotals came from.
Consumables
Tablet
We need an android tablet to proved a GUI for a good user experiance.
| Description |
URL |
Qty |
Cost |
Shipping |
Verified? |
Extended |
| Tablets |
| Samsung Galaxy Tab A |
|
0 |
$75.00 |
$0 |
|
$0.00 |
| Samsung Galaxy Tab S4 |
|
1 |
$250.00 |
$0 |
|
$250.00 |
| Huawei MediaPad M5 |
|
0 |
$250.00 |
$0 |
|
$0.00 |
| |
|
0 |
$200.00 |
$0 |
|
$0.00 |
| |
|
0 |
$100.00 |
$0 |
|
$0.00 |
| |
|
0 |
$217.00 |
$0 |
|
$0.00 |
| Accessories |
|
|
|
|
|
$0.00 |
| Micro USB OTG Charge |
ebay: |
1 |
$2.95 |
$0 |
|
$2.95 |
| |
|
|
|
|
|
$0.00 |
| |
|
|
|
|
|
|
| Subtotal: |
$252.95 |
Possible Systems
Swift Navigation Option
Swift system with one survey unit
Additional Swift survey units
Simple RTK2B Option
Simple system with one survey unit
Additional Simple survey units
Sparkfun Option
Sparkfun system with one survey unit
Additional Sparkfun survey units
Accessories
Peach Power Network Upgrade
It turns out that the best place for our reference GPS station is out in miss Piggy's on the Tickets West pole.
The current data connection to Tickets West is an old nicked, spliced, waterlogged, corroded, indoor only cable that was buried in the ground with no protection. It's a miracle that it's lasted this long. So in order to avoid a last minute emergency, we should jump on this.
| Description |
URL |
Qty |
Cost |
Shipping |
Verified? |
Extended |
| |
|
|
|
|
|
|
| Subtotal: |
|
|
|
|
|
$1,424.89 |
| F Connectors |
summitsource |
5 |
$1.89 |
$1.21 |
|
$15.50 |
| Underground junction box |
True Value |
0 |
$13.20 |
$0 |
|
$0.00 |
| 3" PVC Conduit |
Ace Hardware |
40 |
$17.99 |
$0 |
|
$719.60 |
| 2" Steel Pole |
Coyote Steel |
1 |
$170 |
$0 |
|
$170.00 |
| Ditch Witch rental |
|
1 |
$175 |
$0 |
|
$175.00 |
| Underground junction box |
Jerrys |
3 |
$20.07 |
$0 |
|
$60.21 |
| 3" PVC Conduit |
Jerrys |
0 |
$20.62 |
$0 |
|
$0.00 |
| 3" Steel Pole |
Coyote Steel |
0 |
$224 |
$0 |
|
$0.00 |
| 3.5" Steel Pole |
Coyote Steel |
0 |
$259 |
$0 |
|
$0.00 |
| TRENDnet Modems |
amazon.com |
2 |
$39.99 |
$0.00 |
|
$79.98 |
| Auger rental |
|
1 |
$55 |
$0 |
|
$55.00 |
| RG11 500 FT Underground Cable |
abcconf.com |
1 |
$91.50 |
$58.10 |
|
$149.60 |
Totals
| Description |
Worksheet |
Qty |
Cost |
Extended |
| RTK GIS System |
| Swift System |
Swift_system |
0 |
$2,675.62 |
$0.00 |
| Additional receivers |
Additional_rovers |
0 |
$1,730.36 |
$0.00 |
| SimpleRTK system |
Simple_system |
0 |
$1,641.00 |
$0.00 |
| Additional receivers |
Additional_rovers |
0 |
$677.00 |
$0.00 |
| Sparkfun System |
Sparkfun_system |
1 |
$1,876.68 |
$1,876.68 |
| Sparkfun Rove |
Additional_rovers |
0 |
$680.08 |
$0.00 |
| Tablet etc... |
Tablet |
1 |
$252.95 |
$252.95 |
| Accessories |
Accessories |
0 |
$74.83 |
|
| Peach Power Upgrade |
Peach_Power |
1 |
$1,424.89 |
$1,424.89 |
| Spare Cat 5 |
Ethernet_Cable |
500 |
$0.15 |
$75.00 |
| |
|
|
|
|
| Subtotal: |
$3,629.52 |
| Misc |
| |
|
0 |
$200.00 |
$0.00 |
| |
|
0 |
$35.00 |
$0.00 |
| |
|
0 |
$40.00 |
$0.00 |
| |
|
0 |
$199.44 |
$0.00 |
| |
|
0 |
$25 |
$0.00 |
| Misc HW |
|
1 |
$300 |
$300.00 |
| Subtotal: |
|
|
|
$300.00 |
| |
|
| Totals: |
|
|
|
$3,929.52 |
| Alocated: |
|
1 |
$3,929.52 |
$3,929.52 |
| Difference: |
|
|
|
$3,929.52 |
| Percent Over: |
|
|
|
0.0% |
--
ClifCox - 17 Feb 2020
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