Field-Map technology. Forestry oriented tool for measurement and mapping in difficult conditions. GPS workshop Montpellier, France

Transcription

1 Field-Map technology Forestry oriented tool for measurement and mapping in difficult conditions GPS workshop Montpellier, France

2 Measuring forest Be ready for: - no or weaker GPS signal (forest canopy, valleys and ravines) - harsh measurement condition (obstacles, slope) - visibility limitation (dense under-storey) - no clear boundary identification + lower expectations

3 Field data collection alternatives (Forestry sector) Traditional equipment Field computer Electronic devices Paper forms

4 +/- of the traditional technology + cheap solution + easy application (low qualification demand) - lower efficiency of data collection - high amount of errors (measurement errors, transcription) - measurement difficulties (slope, rugged terrain) - limited possibilities - no possibility for data validation in the field

5 +/- of the computerized technology - costs of the technology - requirement of the field-crew training + up-to date electronic equipments + higher productivity of fieldwork + higher precision of measurement + possibility to collect other information (i.e. stem profile, crown profiles/projections etc.) + digitized data directly in the field + smooth data processing + extended possibility for data validation + context of existing data

6 Field-Map technology hardware components (field computer, laser rangefinder, compass module or anglecount device, GPS, monopod or tripod, poles, reflectors and accessories) software bundle Field-Map Project Manager Field-Map Data Collector for Windows OR Field-Map Data Collector LT for PDA s Field-Map Data Processing tools

7 Hardware alternatives Higher precision, lower efficiency & mobility Lower precision, higher efficiency & mobility

8 Windows x PD s Field-Map Data Collector (Windows) Field-Map Project Manager Field-Map Project Manager Data Processing Tools x Field-Map Data Collector (Windows platform) x Field-Map Data Collector LT (PDA s) Field-Map Data Collector LT (PDA s] Field-Map Project Manager

9 Geographic entities point: [X,Y,Z] line: [X,Y,Z], length polygon: [X,Y,Z], perimeter, area tree: point + polygons (tree basal area, crown projection, crown profile, stem profile) deadwood: center line + polygon

10 Database hierarchical structure standard industry formats (ESRI Shapefile, Paradox, MS Access, My SQL) attributes numeric, alphanumeric strings, logical, date, time, memo, picture, video, voice memo, category - lookup list, data submitted by electronic equipment (e.g. height, diameter)

11 Other related functionality on-line support of electronic equipments (GPS, laser, angle-count device, ) user defined global co-ordinate system on-screen visualisation lines to polygon transformation Bowditch transformation (closing polygon) line smoothing function background maps context of existing data

12 GPS and electronic equipments direct support of GPS (automatic transformation of co-ordinate, NMEA 0183 format) on-line connection to electronic equipments possibility to switch Field-Map Data Collector map form

13 Co-ordinate system global existing map projection (predefined national co-ordinate systems or user-defined map projections) meridian convergence local (Carthesian) Field-Map Data Collector definition of global co-ordinate system

14 Lines-to-polygons transformation functions for line cleaning and polygon building wizard covering whole functionality Field-Map Data Collector Polyshape wizard

15 Bowditch transformation transformation of traverse + related point layer 2 GPS points or closing traverse to the origin Field-Map Data Collector Bowditch transformation

16 Line smoothing user controlled smoothness more natural-like boundaries Field-Map Data Collector line smoothing

17 Background maps raster (i.e. aerial photo/satellite image) and vector formats on-screen info from linked database Field-Map Data Collector active background maps

18 Validation test Test scheme: 3 polygons of different size and different shape - rectangular 0.36 ha - elongated 0.81 ha - polygonal 5.61 ha 6 series with 4 repetitions 2 sets of equipments (same set-up) 2 operators Procedure: 1. testing polygon establishment 2. testing polygon reference measurement 3. test measurement 4. data processing 5. conclusions

19 Testing polygon Testing polygon in Radlík

20 Reference areas & perimeters Total station Leica TRC 307

21 Test measurement Field-Map set-up (4.1 kg): laser rangefinder/clinometer ForestPro electronic compass MapStrar II. PC Dolch E 100 monopod GPS SXBlue II. Field-Map Data Collector (for Windows) Methodology & Timetable: Set Antelope vertexes measurement (with re-location to each vertex) three days work for 2 teams including preparation, equipments calibration and data processing 72 measurement (3 fields x 6 series x 4 repetitions)

22 Data processing 1. Pre-processing: closing polygons using Bowditch transformation calculating areas and perimeters using Polyshape EDA - normality test (skewness&kurtosis, Shapiro-Wilk test) - outliers/stragglers identification (Cochran, Grubbs tests) - bias test (Student T test) 2. Buffer calculation - repeatability -variance - reproducibility variance - reproducibility limit

23 Preliminary results Results are not fully compliant with standard test described at due to lower number of parcels and lower number of series. Statistics Polygon 1 Polygon 2 Polygon 3 overall mean area [m 2 ] reference area [m 2 ] reference perimeter [m] bias (percentage of the area) reproducibility limit R reproducibility variance Sr reproducibility limit (buffer) [m]

24 Further steps complete the test (2-3 more parcels and 3 more series) operator, measurement method should be tested source of bias should be investigated precision of total station should be tested other hardware set-up should be tested 1. Flamingo set -2,8 kg (TruePulse with monopod & Toughbook Panasonic) 2. TrueAngle set - reference area measurement (TrueAngle, ForestPro & tripod) Set Stork

25 Thank you for your attention IFER Institute of Forest Ecosystem Research Ltd. Jílové u Prahy, Czech Republic &