Bill Cusworth CREATING ORIENTEERING BASEMAPS USING LIDAR DATA

Transcription

1 Bill Cusworth CREATING ORIENTEERING BASEMAPS USING LIDAR DATA 1

2 BILL CUSWORTH Started Orienteering in 1992 in Seattle with Cascade Orienteering Club. Started making maps in 1993 and became more serious in 2008 when Lidar started becoming available in Washington State Moved to Santa Rosa, California in Founded Nav-X Map Adventures in 2016 Have taken 2.5 GIS classes at Santa Rosa Junior College (where I work in Chemistry) Currently make about 1-2 maps per year 2

3 PROJECTS Several in Washington State Putney Woods ( 08), Lord Hill ( 09-10, 16), Ft. Ebey ( 10), Ft. Casey ( 11) Land s End Sprint map NW tip of San Francisco ( 11) Boggs Mountain in Lake County mapped veg boundaries that all burned in wildfire ( 13) Granite Bay, Folsom Lake SRA Used ArcGIS for basemap ( 14) Bon Tempe Lake mostly field checking ( 15) Dinkey Creek, used GDAL to draw contours ( 16) used for NA Rogaining Champs 2016 Updates to Morgan Territory near Livermore, Northstar Resort in Tahoe area, & Annadel SP, & Camp Tamarancho ( 12-17) Mt. Laguna near San Diego used ArcGIS to georeference map using rubbersheeting method (not recommended) ( 17) Deer Creek Hills Used QGIS to draw contours ( 16-17) Glen Alpine Canyon used KP for first time ( 17) 100 Lakes, Tahoe National Forest used OCAD 2018 for first time ( 18) Tahoe National Forest around Northstar Resort to be used WRC

4 OVERVIEW OF STEPS TO MAKE A MAP Make a basemap a good one will reduce field checking time. Divide the area into tiles based on desired field check scale - determined by your pace count. I use 1:2850 (2 paces/mm) or 1:4275 (3 paces/mm). If using a laser range finder, use an even number scale like 1:4000 or 1:5000 Place registration marks in each corner of each tile. Make sure there is some overlap between the tiles. Print base map and place on flat board, cover with mylar sheet, attach compass & ruler and hold everything together with binder clips. Mechanical pencils - Pentel 0.5mm, black, blue, & red (waterproof) Devise number/letter system for feature codes Strategies: Check all features from basemap, follow ridges and valleys, find places that look interesting, start with trail networks and fill in between Do field checking. When each board is completed, scan fieldwork, load into map program as a background map and align (F9 in OCAD) field notes to basemap using registration marks. Trace field notes. 4

5 GETTING STARTED Vector (points & lines) vs. Raster (pixel image) data files 2 main things that you need for a basemap Contours (from LiDAR) vector lines Aerial imagery raster Other components: Vegetation height raster (from LiDAR) Vegetation density raster (from LiDAR) Shaded relief Hillshade & Slope angle rasters (from LiDAR) Knolls & depressions, single trees vector point(from LiDAR) Cliffs vector or raster (from LiDAR) Open Street Data - vector GPS data vector Hydrology -? 5

6 COORDINATE SYSTEMS & GEOREFERENCING Georeferencing with Real-World Coordinates so your data will all line up perfectly! No need for F9 (adjust template) in OCAD which often doesn't work well. 2 kinds of Coordinate Systems (CS s) Geographical (3D, lat + long, spherical) WGS84, NAD83, NAD27 Projected (2D, Cartesian) UTM(meters), State Plane(ft) WGS84 + NAD83 are within 1m of each other When using old legacy OCAD maps in paper coordinates usually need to use "Rubbersheeting" method to properly georeference because of distortions in the original base map. GIS programs can do all kinds of coordinate transformations. OCAD (later versions) & OOM can load data in various CS's OCAD can t load geographical coordinates (lat + long) but OOM can load this CS. 6

7 Standard system used everywhere - units are meters Cylindrical secant projection over 6 deg longitude slices yielding 60 zones in the northern hemisphere and 60 zones in the southern hemisphere. Maximum scale error is less than 0.1% Except for the central meridian, Grid north is up to 3 degrees shifted from true north. UNIVERSAL TRANSVERSE MERCATOR (UTM) COORDINATE SYSTEM 7

8 INTRO TO LIDAR 8

9 INTRO TO LIDAR - RETURNS 9

10 LIDAR (LIGHT DETECTION AND RANGING) Laser pulsed from plane to surface Reflected light recorded as returns Returns are classified by type (ground, water, vegetation, building, etc.) Raw data point cloud data file complex raster, file extensions:.las &.laz.laz is zipped form of.las (1/7 file size) 10

11 DIGITAL ELEVATION MODELS 11

12 DIGITAL ELEVATION MODELS (DEM) Ground (last) returns are collated into a raster Digital Terrain Model (DTM), also called Digital Elevation Model (DEM), i.e. DTM = DEM First returns are collated into a Digital Surface Model (DSM): Vegetation height = DSM-DTM Contours & shaded relief are created from DTM don t need full LiDAR data USGS DEMs are based on Lidar data if it is available for an area (1/9 arc-second resolution) 12

13 ADVANTAGES OF LIDAR Very accurate contours (but need smoothing) Detection of roads, trails, other objects (boulders, rock walls, etc.) by shaded relief Detection of cliffs, knolls, & depressions by slope angle Detection of clearings (canopy height < 0.1m) and veg boundaries without influence of shadows. Detection of vegetation density from LiDAR canopy height and near-ground returns. More near-ground returns = high density = lower runnability 13

14 OCAD ORIENTEERING COMPUTER- AIDED DESIGN Released 1989 License Fee ~ $145/yr Windows only Recent versions have GIS functions such as LiDAR processing Rubbersheeting OSM import OOM OPEN ORIENTEERING MAPPER Released 2014 Open Source, no fee Windows, Mac, Android No LiDAR processing but has better import and drawing functionality. Can use in combination with GIS programs Had trouble with symbol icons ORIENTEERING MAP PROGRAMS 14

15 COMMERCIAL (GUI) HOME GROWN (NO GUI) ArcGIS by ESRI can get license for $100/yr QGIS - free LAS Tools - free OL-Laser - free OCAD ~$145/yr Smoothed contours like KP Vegetation mapping like KP Automatic cliff detetction like KP Rubbersheeting georeference Import OSM data Import State plane data Karttapullautin (KP) Smoothed contours - shows depressions & form lines Outputs vegetation density map w/ cliffs & buildings Terje Mathisen tools Outputs vector file for vegetation Stiches contours together but does not smooth them PROGRAMS THAT PROCESS LIDAR 15

16 KARTTAPULLAUTIN (KP) No graphical interface uses command line or you can drag and drop the data file onto the program file. Accepts only raw data as input (.las or.laz) uses LAS tools to process data. Outputs vector contours that are smoothed and deviate slightly from true elevations to show shapes better and includes form lines. Outputs form lines and highlights depressions in purple. Outputs vegetation density map as a raster file contains buildings. Outputs cliffs and knolls as vector files. Very slow. Contours are great but clearings were not accurate. Had trouble creating merging tiles. 16

17 SOFTWARE RECOMMENDATIONS Have some money to spend: OCAD 2018 Have no money: Karttapullautin + Open Orienteering Mapper 17