GEOSAP Standards & Mapping Guide v1.1

This page will collect standards that ensure that all GEOSAP-mapped ski areas have similar look-and-feel, and that applications developed to generate statistics about the areas will work on all trail maps. Trail map developers will self-rate their maps to identify what level of standards have been met, and if done correctly, this should determine what level of statistics can be generated for a given trail map. When you have finished mapping, read the Guide To Submitting Ski Area Maps and post your map to GEOSAP!

Current GEOSAP Standards Version Number: 1.1
All trail maps complying to the standards on this page should be marked as GEOSAP Standards Version 0, or S0.

Project Organization

Each trail map will be kept within a folder, and these folders in turn will be kept within a folder for each state (named with the state's two-letter abbreviation). This is to facilitate organized distribution of the GEOSAP trail maps in one large download, by state, or by individual area.

Ski Areas

The ski area folder's view should be rotated so that it is generally consistent with the perspective used in the official ski area trail map. The folder will have three sub-folders labeled "Lifts", "Trail Boundaries", and "Trail Centerlines. The order of the lift and trail names will be as similar as possible to the official trail map.

Tubing and cross-country trails should not be included in the maps at this time. The only exception is that lifts used both for tubing and for skiing/snowboarding may be included.

If an area of the ski area is blocked by a cloud, attempt to overlay the trail map over the Google Earth imagery and trace the trails as best as possible. If high-resolution imagery is not available for a ski area, note the lack of imagery and date on the corresponding page in the wiki and move on. Google Earth updates regularly, so check back on the imagery at a later date.

Once you have completed a map of a ski area and uploaded the KMZ file to the site, send an email to the site administrators. The new map will be added to the GEOSAP global map and a credit given to the member who completed it.

Lifts

Lifts should be red paths, and will generally consist of two points: one at the top, and one at the bottom. Intermediate points should be provided to identify when a lift turns or to identify midstations.

Map developers should try to identify the center of each lift wheel, not the loading/unloading area. For high-speed quads, and other large lifts where a lift building is frequently all that is visible, the points should be placed at a point approximately 80% from the front of the lift building. Recognizing that this is not always possible, the associated building/shack is a valid alternative.

Mid-Stations

square.png

When a lift has a mid-station, a folder should be created for the lift. A placemark with a square icon should be placed on the mid-station. Both the path for the lift and the placemark for the mid-station should be placed in the folder for the lift. The path for the lift should have an intermediate point located on the mid-station. Custom views should be set for the lift path, and for the lift folder.


Trail Centerlines

Trail centerlines should be paths, green for beginner, blue for intermediate, and black for advanced or expert. The paths should be placed within the "Trail Centerlines" folder. No minimum or maximum spacing has been specified thus far, but points should be closely spaced enough to reflect small bends in the trail, and to appear smooth when one zooms back to view the whole mountain. If a ski area uses non-standard difficulty levels (such as Camelback's double-greens or Wachusett's beginner/intermediate and intermediate/advanced trails), it is up to the map developer to categorize it into one of the three standard trail ratings.
Areas that are glades and are marked only as a general area on a trail map still need a centerline so that statistics can be computed. However, this centerline should be unchecked, and instead the trail boundary (with no fill but an outline colored appropriately for the difficulty) should be checked and visible.

Multiple Ratings

difratings

When a trail is marked on the trail map as one trail with two sections of a different rating (i.e. One steep section rated black and one easier section rated blue) two different trails should be created, each reflecting the difficulty level of the section it represents. These two trails should be placed in a sub-folder within the trails folder titled with the name of the trail. This will keep the length, trail count, and pitch statistics correct, while maintaining an accurate map.

Intersections

In areas of intersection (particularly lift loading/unloading areas), the easiest trail should generally "win" and more difficult trails should connect to it. This reflects that these areas are generally flat and that most ski areas try to provide easier connections to allow less skilled skiers to get to and from lifts. Trails should come within 50' of the lift start and end point so that their full length is reflected. They may follow the direction that a skier would naturally take due to unloading ramps or other directing features. In general, the objective is to give the area "full credit" for the length of its trails so that its statistics are accurate.

Coincident trails

If two trails share a section, a decision must be made on whether to break one of the trails in two, or to allow them to coincide as shown below:

coincident_trails.jpg

Benefits of keeping trails coincident:

  • Plots may show the trail as a continuous section, the way it would be skied.
  • If one trail is open and the other isn't, statistics are accurate and there is no apparent gap in the trail.

Benefits of splitting up one of the trails:

  • Ski area doesn't get "double credit" for the length of the shared section.
  • If the trails are different difficulties, this avoids including a section of easier grade in the statistics for the higher difficulty level.

If the shared section is brief (<500'), we recommend keeping both trails intact, but if longer than that, one should be split up, with both sections having the same name. This will keep the maximum error in statistics small. The more difficult trail should be the one that is split up, and if they are of the same difficulty, it's up to the map developer's judgment, weighing factors like which one is bigger, more popular, or more likely to be open.

Chutes and Bowls

In an area of chutes and bowls, trail centerlines should be placed down the center of the chutes or down the center of a bowl. If multiple trails are listed on the map in a bowl, place a trail centerline down the approximate path of each of the bowl trails. Centerlines should be created for each trail in a bowl, but only one area boundary should be created for each bowl.

Please note that a trail boundary is shown as filled below, but in a standards-compliant map only the edges would be visible:

BowlTrails.jpg

Trail Boundaries

Trail Boundaries should be marked with polygons, filled and outlined with the color corresponding to their difficulty: green for beginner, blue for intermediate, and black for advanced or expert. Normal trail boundaries should be unchecked and not visible. Glade trails should have a boundary which is outlined, not filled, and is checked and visible. The boundaries should be placed within the "Trail Boundaries" folder.

Multiple Ratings

When a trail is marked on the trail map as one trail with two sections of a different rating (i.e. One steep section rated black and one easier section rated blue) two different trails should be created, each reflecting the difficulty level of the section it represents. These two trails should be placed in a sub-folder within the trails folder titled with the name of the trail. This will keep the length, trail count, and pitch statistics correct, while maintaining an accurate map.

Intersecting Trails

When trails intersect but do not cross, the boundaries of each should be reduced such that each has approximately half of the shared area, making total skiable acreage statistics accurate. Please note that these trail boundaries are shown as filled, but in a standards-compliant map only the edges would be visible:

coincident_trails_filled.jpg

When trails cross each other, the above method is not possible, so one of the trails must "win" based on the same rules described in the "Trail Centerlines | Intersecting Trails" section. The other trail's boundary must shrink to near zero area during the shared section, so as to not inflate the skiable acreage statistics.

Chutes and Bowls

In an area of chutes and bowls, one polygon should be traced around the perimeter of the chute area or the bowl in order to represent the open aspect of these types of trails. Centerlines should be created for each trail in a bowl, but [javascript:; only one area boundary should be created for each bowl. If it is unclear whether the area should be mapped as a bowl, it is up to the developer to make the decision.

Please note that this graphic shows some items as filled, but in a standards-compliant map only the edges would be visible:

BowlTrails.jpg
BowlOutline.jpg

Ski Area Boundaries

Ski area boundaries should be polygons with no fill (so as to not obscure the more important map details), and a white border. The goal should be to identify all in-bounds terrain, even that which is not a trail or glade. This line will be approximate in most cases and is used to produce less critical statistics, so it does not need to have closely spaced points like a trail boundary. When a trail edge is being followed to create the area boundary, keep the boundary just outside the trail edge. This makes it look cleaner and makes sense since most areas allow skiing at least a few feet outside the trail boundaries.

Coloring

Trails should be marked with a color which corresponds to their difficulty. Beginner trails should be marked green (1,153,0), intermediate trails marked blue (16,109,179), advanced or expert trails marked black (0,0,0), terrain parks marked orange (255, 128, 0) and lifts marked red (255,0,0)

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