Review of NYNJTC hiking map for the Catskills

NYNJTC hiking map for the catskill mountains

Purchase: Purchase Map at NYNJTC - Also available at Rock & Snow at the time of this review
Coverage: Covers the Entire Catskill Mountains
Details - Number of maps: (6) small hiking map for the Catskills Mountains - topo maps generally on the front side and verbiage on the back side
Details - Size of maps: Folded: 7-1/2" x 4" - Total topo map area: 1494 ci (excluding verbiage)
Details - Map #141: Folded: 7.50" x 4.00" - Unfolded: 22 x 20 (front) & 12 x 7 (back) - total topo map area: 524 ci
Details - Map #142: Folded: 7.00" x 3.75" - Unfolded: 22 x 14 (front) - total topo map area: 308 ci
Details - Map #143: Folded: 6.50" x 3.75" - Unfolded: 22 x 13 (front) - total topo map area: 286 ci
Details - Map #144: Folded: 6.00" x 3.75" - Unfolded: 18 x 12 (front) - total topo map area: 216 ci
Details - Map #145: Folded: 7.75" x 3.87" - Unfolded: 7.75 x 7.75 (front) - total topo map area: 60 ci
Details - Map #146: Folded: 7.75" x 3.37" - Unfolded: 10 x 7.75 (front) & 4.50 x 5.00 (back) - total topo map area: 100 ci
Durability: Waterproof and Tear Resistant
Type: Topographical with roads and hiking trails
Scale: 1:63,360
Contour: 50 feet per contour interval
One Inch: 1.00 miles
Trail Mileage: Hiking trail mileage done with a wheel in the 1980's
Contour Lines (X & Y axis): Aerial LiDAR (USGS)
Summit Elevation (Z axis): Aerial LiDAR (USGS)

Rating: Poor

Price: $16.95

This is the first hiking map for the Catskill Mountains that has been done with LiDAR. There are some very profound pros and cons to the use of LiDAR. So, before we can even start to discuss our review of the map, it is very important that you understand how LiDAR works and the different types of LiDAR.

History of LiDAR:
Using Aerial LiDAR for building topographical hiking maps has created enormous controversy. There are basically 3 types of LiDAR that can be used to build topographical maps. We will discuss each one, so that you can clearly understand the pros and cons of buying this map. This map uses Aerial LiDAR which has highly accurate contours lines (X and Y axis), but the elevation is inaccurate (z axis). Below we will explain exactly why this is true. But, before we do that you need a very quick history lesson on LiDAR:

LiDAR stands for, "Laser Imaging, Detection And Ranging". The main part of LiDAR is a laser. What makes LiDAR different from a laser is that it is used to measure the distance from the laser to an object and back. The most simple form of a LiDAR device is a electronic measuring tape from your hardware store. You push a button, and it tells you the distance to an object. What makes LiDAR exceptional is that it can send up to 300,000 laser light beam measurements a second, and hit objects miles away.

Lasers were first invented in the early 1960's. LiDAR was invented shortly after the invention of the laser. The first commercial use of LiDAR was to measure the amount of particulate matter in the atmosphere. In simple terms, it measures the amount of pollution in the air, so that they can give the public the Air Safety Rating. Helpful to those who have COPD or Asthma. While LiDAR laser beam can hit an object miles away, it also can fail due to the smallest particles in the air. The thickness of a LiDAR laser beam is around 750nm. The smallest object a human eye can see is 100,000nm. So, the LiDAR laser beam is extremely small, invisible, and fragile.

To build LiDAR maps with elevation, you need a reference point. All elevation maps are REQUIRED to have some type of altimeter to build the map from. Otherwise, the lidar data would have no idea of what the elevations are. So, the accuracy of the altimeter becomes a VERY IMPORTANT part of building a topographical maps. The most accurate altimeters are barometric altimeters. The least accurate are pressure altimeters used on planes.

Today, LiDAR is used forestry, measure the air quality, weather features and events, land surveying, archaeology, Laser radar guns to measure speed of cars, construction sites, etc. There are 3 types of LiDAR for this conversation:

(1) Ground LiDAR - is most commonly used by Land Surveyors for created land maps. It uses a LiDAR unit on the ground with a barometric altimeter. A new application for ground LiDAR is safety devices on cars (collision alerts), and autonomous cars.

(2) Aerial LiDAR - is most commonly used by foresters to calculate the amount of lumber that can be taken out of a forest by loggers. It uses an airplane and shoots the laser directly to the earth, and uses a pressure altimeter as a reference point.

(3) DGPS LiDAR - is most commonly used by construction sites. It uses drone with a LiDAR device attached, and uses a Differential GPS unit on the ground to provide reference point of elevation and position.

GROUND LiDAR:

Ground LiDAR is generally used for situations where the area being surveyed by the Laser is relatively small. Generally it is confined to a couple of acres. Common places where are: (1) Land Surveyor's to survey the land quickly and accurately; (2) Fatal car accidents. It allows the police to accurately measure everything at the accident scene and clear up traffic quickly. The police can then spent an extended period of time reconstructing the accident; (3) Vehicle safety warning systems. Cars that warn you that you have another car in your blind spot, emergency braking, etc; (4) Autonomous Vehicles that drive themselves without the help of a person.

Ground LiDAR will shoot the laser parallel with the earth. In almost all cases, it will use a barometric Altimeter as a reference point for elevation. Barometric Altimeters are reliable within + or - a couple of feet in elevation. They are regarded as the most accurate way to measure elevation. Most barometric altimeters today have an automatic adjustment for barometric pressure. The high quality barometric altimeters will allow the user to enter the barometric pressure manually, and will then adjust it automatically to ensure the highest quality elevation measurement. The margin of error for land surveyors is + or 8-9 inches and +- a couple feet for the barometric altimeter. LiDAR in car accident reconstructions is smaller area, and is usually within +- a couple inches with +- couple feet for the barometric altimeter. It is a highly accurate on the x-axis, y-axis, and z-axis. But, to use it for building a map of an entire mountain range would take an enormous amount of time.

This image is a land survey created by Ground LiDAR

AERIAL LiDAR:

With Ground LiDAR we are sending laser beams parallel with the earth. To make topographical maps, we need to send laser beams perpendicular to the earth. The easiest way is to use an airplane with a LiDAR unit attached to the plane. With the ability to send up to 300,000 laser beams per second to the earth (measure the distance from the plane to earth) seems like a great solution. But, with every great solution, there are limitations of physics and technology.

This image is a land survey created by Aerial LiDAR

The primary use of this type of LiDAR is for forestry. They can use aerial LiDAR to measure the amount of board-feet of lumber that loggers can remove from the forest. Over the past two decades they have refined the computer programs to calculate how wide a tree is, along with it's height to calculate the amount of lumber that can be harvested from the tree. Furthermore, they can often tell what type of species of tree it is. While this seems wonderful, it does have it's problems. Shrubs, thick canopies, steep slopes, decaying tree particles, etc can cause significant problems with elevations (z-axis). They spent over a decades trying to reduce these types of errors. Loggers don't want to be cheated out of lumber that was calculated wrong. The changes to the computer programs reduced the errors from around 15% accuracy to around 65% accuracy. But, the 35% inaccuracies had larger margins of errors. But, overall for loggers, it was an improvement. There is still a lot of errors on elevation (z-axis), but loggers really don't care if the elevation is off by 25'. They only care about the amount of lumber that can be harvested. Accurate elevation doesn't matter too much to loggers.

What does all this have to do with building typographically maps? A lot. The contours lines created by aerial LiDAR are a huge improvement. LiDAR will map the exact configuration of the landscape. For bushwhackers, this is a dream come true. But, too often cartographers want to apply a smoothing algorithm to the contour lines. While smoothing contour lines is aesthetically pleasing to the eye, it doesn't help the hiker orient themselves in the forest. Once contour line smoothing is done, the map is just like a manual surveyed map.

Aerial LiDAR Contour Lines NOT smoothed Aerial LiDAR Contour Lines smoothed

The biggest disadvantage for using aerial LiDAR for topographic maps is the elevation error is huge and just plain unacceptable for hikers. So, let us talk about what those margins are:

Altimeters on Airplanes: While we know that barometric altimeters are highly accurate (within a couple feet). You cannot use them in airplanes. Some airplanes are pressurized, which makes barometric altimeters worthless. You also cannot use them in small planes because they are moving through air, which changes the barometric pressure. Therefore, the FAA requirements the use of pressure altimeters on planes. The small little bent tubes you see near the cockpit are the inputs for the planes altimeters. The FAA has very specific regulations on how they operate, and more importantly, the allowable margin of error. To survey the Catskill Mountains, the FAA allows planes to have a margin of error of + or - 40 feet! That is a massive margin of error! But, in most cases, the margin of error would be smaller, but it would not be nearly as accurate as a barometric altimeter. Even if it was flying in the middle of the jet stream.

Margin of Error for long-distance lasers in Aerial LiDAR: When the police survey a fatal accident, they are usually working within a 75' x 75' area. The margin of error would be around 1-2 inches. Land surveyors have an area of a couple of acres, and their margin of error is around 8-9 inches. But, aerial LiDAR is usually measuring distances from thousand of feet. Their margin of error is around 25-30 feet!

This shows the position of measurement from Aerial LiDAR from the USGS
The margin of error for elevation of the ground is 8-9 meters or about 25-30 feet

The advantage of using Aerial LiDAR for topographical maps is that it can cover a very large amount of land quickly and cheaply. But, the primary disadvantage is the huge margin of error on the elevation. Data for Aerial LiDAR can be downloaded from the USGS or New York State GIS.

DGPS LiDAR:

DGPS LiDAR is a hybrid of Ground LiDAR and Aerial LiDAR. It uses drones that fly 100-200 feet off the ground instead of thousands of feet. For a reference point, they will use GPS barometric altimeters on the ground at strategic locations to transmit those accurate elevations and positions to the drone, instead of a pressure altimeter.

DGPS LiDAR

Since drones fly slowly, barometric altimeters could be used on the drones. This eliminates the large margins of errors for airplane pressure altimeters. Since the maximum height off the ground for drones is 400 feet, you have much smaller margins of errors for the laser measurements. The margin of error for topographical maps for DGPS LiDAR is around 3 feet plus the margin of error for the barometric altimeters. Drawbacks for DGPS LiDAR is that the drones cost around $65,000 each, and you need to have a team hike in and place the GPS units around each and every mountain. The drones can only fly for about 45 minutes. To survey the entire Catskill Mountains would take thousands of hours to complete for a team of workers. Back around 2014, the Smokey Mountain National Park used DGPS LiDAR to survey parts of their park. Maybe someday we might get lucky enough to have DGPS LiDAR done by a group for the Catskill Mountains. But, for right now it is far outside our reach. But, it is where the future is.

Phoenix MiniRanger Drone equipped with a Rigel LiDAR sensor

REVIEW of the 2018 NYNJTC MAP for the CATSKILL MOUNTAINS:

This is the first LiDAR topographical hiking map created for the Catskill Mountains. This map was made with Aerial LiDAR from the USGS. While the contour lines are very accurate, the elevations have significant errors.

Before the map was printed, the idea of using Aerial LiDAR maps was presented instead of manually surveyed maps. The issue of elevation errors was presented that the previous elevations were incorrect. The "proof" that was presented was the survey done in the Smokey Mountain National Park with LiDAR. But, the problem with this argument was that NYNJTC map used Aerial LiDAR (inaccurate elevations), while the Smokey Mountain National Park used DGPS LiDAR (highly accurate elevations). It was like comparing apples to oranges.

There was further discussions that stated that the Catskill Mountains have never had their elevations measured. The first survey of parts of the Catskill Mountains were done in 1825. Extensive elevations with a professional barometric altimeter was done in the second half of the 1800's by Professor Guyot. Those measurements were published in Rusk's famous hiking guide in 1885. Some of those measurements are still used today. The USGS has done elevation measurements several times on almost all Catskill Mountain Peaks. Many other groups have also done those elevation measurements. Many of the common summits of the Catskill Mountains have been measured over hundred times. Aerial LiDAR requires a pressure altimeter to make it's measurements. It should be noted that there some new GPS/altimeters that can be used on airplanes, but they are stand along devices that are not integrated with the LiDAR sensors. In the future, this may be possible, but the ground elevation margin of error would still be at 25-30'. Since the Catskill Mountain summits have been surveyed manually with a professional altimeter many times, it is impossible that the assertions that Aerial LiDAR is more accurate then ground barometric altimeters. The USGS does have official elevation measurements of all the summits in the Catskill Mountains, and they do not match the NYNJTC cartographer's claims.

If you are only going to follow official DEC trails and you do not care about elevations, this map may work for you. But, if you plan on using a GPS and/or bushwhacking, you may have significant problems with this map. Some people have concerns that a hiker may use this map, and the incorrect elevations may cause them to become lost. The NYNJTC has been building maps for many years, and they are well liked by some hikers. We hope that in 2020, when the next version of the Catskill Maps come out, that they get the problems corrected.

Things we DIDN'T like:

LiDAR - maps are the future, and we love new technology that makes hiking better. But, with any cutting edge technology, you have to make sure that you don't bleed from it. We also found that the scale of 1:63,360 is too small for LiDAR contour lines to help. We would prefer to see 1:24,000. Then LiDAR contour lines would be helpful.

Contour Lines - made with LiDAR should have some smoothing. But, not too much smoothing that would wipe out important features that are vitally important to bushwhackers. With the LiDAR contour lines completely smoothed out on this map, there is no advantage to using LiDAR.

Elevations - are incorrect approximately 25-35% of the time. This is enough of a concern that we placed a poor rating on this map. We are concerned that a hiker might become confused and get lost, injured, or killed.

The trail mileage - are somewhat close. Each section of the trail is given mileage, but it is rounded off to 0.05 of a mile. It would be better if it was rounded off to 0.01 of a mile. The mileage is also not very accurate. It was done decades ago with a walking wheel. Walking wheels work poorly on rocky trails. Most of the Catskill Mountain trails are rocky. The organization really needs to get a gps and measure the trail mileage themselves.

The Color of the maps - is the old USGS map green. It is okay to read on a good day. But, difficult to read in low light, or in difficult weather conditions. With the contour interval at 50' did make it difficult.

The trails on the map - are just the official ones. There are hundreds of miles of unofficial trails that are NOT on the map. Some of them are heavily used. The mountain bike trails (Multi-Use Trails) were poorly done. But, in all fairness, the multi-use trails on the other maps were done poorly or not at all. Mountain biking is the fastest growing sport in the Catskill Mountains.

Hiking Trails - are loosely drawn on the map. They have the appearance of being GPS tracks, but they do not come close to matching known GPS tracks. Hikers like the trails be be actual gps tracks that show every twist and turn of the trail. Often times experienced hikers want to know exactly where they need to leave the trail. This map will not help you with this.

North-South Lake - has some of the best hiking in the Catskill Mountains. Most maps have a separate section for North-South lake. This map has one, but it is very small, and missing some features.

Names of locations - are often missing. Some tent sites were also missing, or placed incorrectly.

Road Mileage - between major road intersections is missing. But, to be fair, none of the maps have this. For example, how many miles do you have to drive from Exit 19 of the Thruway to Rt 214 in Phoenicia. This is useful for traveling to the mountain you want to hike.

Map Size - has significant controversy. Most hikers do not like having six separate maps for the Catskill Mountains. They would prefer 1 or maximum of 2 maps. Most complain that they end up losing one of the maps, and have to rebuy the maps all over again. We also did not like the verbiage of hiking distances on the back of the map. The mileage is already on the map. They could have better used that space to make the scale of the map larger.

Things we DID like:
Map Print - is very good. The font is easy to read. It is not a readable as the AMC map, but still very good. Some road didn't have names, but they were generally small roads. Most roads were named. This map also have very little advertising on it. They do plug a few local organizations.

Emergency Phone Number - is listed on the map. But, it is not the correct phone number. The map has (877) 457-5680 printed on it. The real emergency number is (518) 408-5850. The Toll-free number is for law enforcement in Regions #1 and #7. The Catskills are located in Regions #3 and #4. I am sure that if someone calls the Toll-free number they will handle it for them. But, the staff at NYNJTC should have verified this before printing the map.

View Points - are listed on the maps. Over 95% of the view points are listed on the maps as stars. But, there are a few that are missing.

Map material - is tyvek. It is waterproof and rip resistant. Map Weight is good. About average. Heavier material then the AMC map, but lighter then the Nat Geo map. The finish of the map is a satin finish, where the Nat Geo map was glossy.

Price of the map - is high.

Sample of the Map Format

Poor view of the trails for the
Fun Loops and Elm Ridge

US Coast Survey Signal - Post marker
for the Catskill Mountains
Installed in 1825

USGS survey marker on ALL
Catskill Mountains Summits
3 installed per summit

Professional GPS/Altimeter
designed for DGPS LiDAR

Phoenix MiniRanger Drone with a
Rigel MiniVUX LiDAR Scanner/Sensor

Links and References:

Rock & Snow

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