Satellite Image 3D Model Aerial Survey Report 2016

2016.3.1 Satellite Image 3D Model Aerial Survey Report 2016

GeoNet, Inc. Hiroyuki Hasegawa

Introduction Orienting German style GIS, which realizes National Information System and named （GeoInformationsSysteme:GISe）, new guideline for cadastral survey specification is proposed, established and evaluated. This guideline is based on 3D cadastral survey and 4D Image Map Archive, and is to be promoted for National Land Survey, especially for mountainous area which covers 70% of the national land. This report deals with mainly accuracy evaluation, efficiency assessment and applicable feasibility. Aerial Survey, especially photogrammetry has pursued the highest positioning accuracy of 3D image models over 100 years worldwide, constructing central projection 3D image models with cameras. In 21st century, high resolution image satellites provide us belt-like satellite imagery by line sensors mounted on satellites, which produce non-centrally projected 3D image models from distant exposures. Late Dr. Atsushi Okamoto of Kyoto University was the pioneer in this field to form 3D image models, theory and accuracy evaluations, and reported his paper in 1999 at American Society of Photogrammetry and Remote Sensing annual convention. This achievement and evolution in photogrammetric 3D model formation is now realized on the state of the art system on 3D display type note book PC, based on 3D-Globe and map projections of 3D-CAD environment. Here satellite 3D stereo image models are combined and associated with 3D-CAD architectural design models in 3D landscape, and revitalize historical reality with regional perspective views. We are now to construct 4D Image Map Archive to realize Historical Reality with 3D image models to represent, measure and foreseen global events on the earth. This kind of concept and methodology ensures us the basis of technological standard for the National Land Survey Act and Cadastral system, then we propose here “Technical specification of cadastral survey with Satellite Image 3D Model Aerial Survey”.

1. Purposes Starting from our practical development status for 3D global mapping with 3D image models of high resolution satellite imagery, here we investigated three major items as follows; (1) Current situation survey of the world’s advanced systems of Satellite Image 3D Modeling (2) Introduction of accuracy evaluation reports and referenced technical specifications (3) With experiments in Japan, methodological analysis and accuracy/efficiency research

2. General outline 2.1 Current situation survey of the world’s advanced systems Overview of satellite image 3D modeling as of 2016,3D image model derived from centrally projected stereo camera images has been constructed as a spatial similarity transformation model as the fundamental concept of photogrammetry which has been established more than 100 years. Here we can remember 3 stages of satellite image 3D modeling after development of analytical stereo plotter in 1970’s. Using Landsat imagery was first used with relative orientation for aerial photo 3D image modeling, and not succeeded. Later, direct solution such as exterior orientation of bundle adjustment was experimented on analytical stereo plotter, using film based stereo satellite imagery, before launching of high resolution image satellites. The first breakthrough of satellite image 3D modeling was the presented paper of late Dr. Atsushi Okamoto in ASPRS convention in 1999, before the first launch of high resolution image satellite. Some non centrally projected image models were formulated, simulated and experimented with SPOT imagery of 10m pixel size on the ground. As a result, the accuracy at check points reached to half a pixel size as standard deviations in x,y,z coordinates. This paper opened the possibility of belt-like satellite imagery by line sensors, proposing different transformation models from spatial similarity transformation. Since then, relative orientation of satellite stereo imagery has been conducted by rational function parameter coefficient approaches, to realize 3D image models with small amount of parallaxes on digital stereo plotters. As an extension of this approach, some representative map projections accept 3D topographical mapping in 3D-CAD environment, and serve as a substitute of analog/digital aerial cameras for 4D Image Map Archive Designed Aerial Survey with 3D image models. Some representative examples are introduced as follows;

2.1.1 Okamoto-3D satellite models in ASPRS1999 Late Dr. Atsushi Okamoto organized methodological investigation, numerical simulation and accuracy evaluation projects on satellite 3D image modeling with belt-like satellite imagery by line sensors.

1 The presented paper and the patent of major concept are succeeded until now, and introduced as follows.

“ Geometric characteristics of alternative triangulation models for satellite imagery “; 1999 American Society for Photogrammetry and Remote Sensing annual symposium

GEOMETRIC CHARACTERISTICS OF ALTERNATIVE TRIANGULATION MODELS FOR SATELLITE IMAGERY

Atsushi Okamoto* Kyoto University Tetsu Ono Kyoto University Shinichi Akamatsu Kyoto University Clive Fraser University of Melbourne Susumu Hattori Fukuyama University Hiroyuki Hasegawa PASCO Corporation * Dr Atsushi Okamoto tragically passed away on Feburary 13, 1999 and this paper, which has been compiled by his colleagues, represents one of the final contributions by this well respected Japanese research photogrammetrist.

Abstract With the forthcoming introduction of high-resolution earth observation satellites, it can be anticipated that the volume of terrain data acquired from satellite imagery will rapidly and significantly expand. This suggests that it may be an opportune time to evaluate different approaches to 3D orientation models for satellite line-scanner imagery. There are a number of models available, each characterised by different assumptions and accuracy. In this presentation six different satellite image orientation/triangulation models are evaluated through their application to stereo SPOT imagery covering known ground point arrays (i.e.testfields). The paper discusses the geometric characteristics of these six different approaches and provides an account of the accuracy attained in experimental application of the different models.

Image 2.1 Late Dr. Okamoto at Parameter Estimation Satellite Surveying seminar on 1998.11.23 and presented paper in ASPRS1999 convention ( ref. ; attached file No. 1)

Next, current representative Rational Parametere Coefficient: RPC approaches are listed.

(1) THE AFFINE PROJECTION MODEL FOR SENSOR ORIENTATION: EXPERIENCES WITH HIGH-RESOLUTION SATELLITE IMAGERY T. Yamakawa , C.S. Fraser Department of Geomatics, University of Melbourne, Melbourne VIC 3010, Australia [email protected], [email protected] Commission I, WG V/5 ISPRS Journal of Photogrammetry and Remote Sensing ; Vol.58, Issues 5-6 July 2004 pages 275-288

2 (2) AN EVALUATION OF RATIONAL FUNCTIONS FOR PHOTOGRAMMETRIC RESTITUTION. Ian Dowman* and John T. Dolloff** *Department of Geomatic Engineering, University College London, UK [email protected] **BAE SYSTEMS Mission Solutions, San Diego, CA, USA [email protected] International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000

(3) ACCURACY EVALUATION OF RATIONAL POLYNOMIAL COEFFICIENTS SOLUTION FOR QUICKBIRD IMAGERY BASED ON AUXILIARY GROUND CONTROL POINTS Yun Zhana Chun Liua,b Gang Qiaoa a Department of Surveying and Geo-Informatics, Tongji University, Shanghai, China b Key Laboratory of Advanced Engineering Surveying of State Bureau of Surveying and Mapping, China Commission VI, WG VII/6 The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008

2.2 World standard accuracy evaluation and technical specification As of 2016, satellite 3D image modeling with RPC orientation files is evaluated in accuracy and yield practical applications. This representative example is the accuracy evaluation by Prof. Clive Fraser of GeoEye-1 satellite image stereo model taken in 2005.This achievement is reported in ASPRS:PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING June 2009 , and furthermore has become the specification of ASPRS Positional Accuracy Standards for Digital Geospatial Data (EDITION 1, VERSION 1.0. - NOVEMBER, 2014).

Image 2.2.1 Positional_Accuracy_Standards-ASPRS and Image 2.2.2 Prof. Clive Fraser : The University of Melbourne;Home Page Next, “ Georeferencing Accuracy of GeoEye 1 Imagery” : by Clive S. Fraser and Mehdi Ravanbakhsh is fully introduced with copied document.

Image 2.3.1 “ Georeferencing Accuracy of GeoEye 1 Imagery” ； Page 1

Image 2.3.2 “ Georeferencing Accuracy of GeoEye 1 Imagery” ； Page 2

Image 2.3.3 “ Georeferencing Accuracy of GeoEye 1 Imagery” ； Page 3

Image 2.3.4 “ Georeferencing Accuracy of GeoEye 1 Imagery” ； Page 4

Image 2.3.5 “ Georeferencing Accuracy of GeoEye 1 Imagery” ； Page 5

This satellite 3D image model is now established as measurable 3D image model on digital 3D photogrammetric measuring system: Summit Evolution, associated with 3D-CAD ( AutoCAD Civil3D), to measure and display 3D vector features on 3D image model. 3 dimensional terrain model (DTM) is, as TIN; Triangulated Irregular Network) and/or point crowd, the basis of land/road designing, landscape analysis and volumetric computation of construction sites. As an extension of 3D image model, 3D-diorama model could be manipulated on cadastral system as national land information systems (GeoInformationsSysteme; GISe) . The author shows 3D-CAD image map model on Summit Evolution from satellite 3D stereo image model of Tasmanian GeoEye-1 model, related to the accuracy evaluation test and 3D mensuration of terrain features.

Image 2.4.1 Summit-Hobert-GeoEye1 satellite image 3D model

Image 2.4.2 3D Image Map on Summit-AutoCAD( UTM coordinate system )

Image 2.4.3 Tasmania-Hobart ：Google Earth query screen

Image 2.4.4 Hobart-Tasmania-Australia-Globe 3D-diorama on Autodesk Infraworks2014

Image 2.4.5 DEM-OrthoMosaic-Tasmania-Globe on Autodesk Infraworks2014

Image 2.4.6 Generated DEM and Ortho-Mosaic on 3D diorama with Autodesk Infraworks2014

11 As a technology to form 3D (stereo) image model, photogrammetry has mainly used centrally projected images, and has 2 major processes of Orientation of single model and aerial triangulation of multiple models. The fundamental concept is a spatial similarity transformation of 3D image model into the reference (ground) coordinate system. 3D image models from images are configured by bundle adjustment of bundle of rays from lens projection center, as the most evolved stage of this technology.

Image 2.5.1 Photogrammetric 3D image modeling ( Central projection：3D stereo image model) Satellite imagery is belt-like image from line scanner, and is extracted as window-like images out of 3 line sensors. At early stages of image satellites, using one line scanner, adjacent satellite loci provided a set of common stereo images ( Cross the truck ),which were imaged in different time points. In recent days,3 line sensors with forward, nadir, backward sights ensure high resolution imagery to construct stereo 3D images (Along the track).

Image2.5.2 Super Photogrammetric 3D image modeling (satellite stereo 3D image model)

12 2.3 Kyoto experiment 2016: methodological research and accuracy evaluation with WorldView2 images

Satellite stereo images have different geometric characteristics from centrally projected camera images, which form stereo 3D image model. For satellite stereo 3D image models, Rational Parameter Coefficient method is commonly used for these years. Formerly this type of stereo 3D image models were constructed by separate time point images covering the research area. This type is so called Cross Track image model. Nowadays, image satellite often mounts 3 sight line scanners, so that they take the same time point images along the track of a trajectory. Later combination out of 3 sight images produces stereo 3D image models with relative orientation parameters. Rational Parameter Coefficient approach is successfully applied for 3D image modeling. Comparing with the process of centrally projected stereo models, different relative orientation procedures are conducted, and the characteristics of oriented models are to be investigated and evaluated with respect to their mathematical models. Also the absolute orientation process could be different from centrally projected stereo model, to be measured with 3D-CAD system.

Image 2.6.1 SPOT stereo model 1999 ： Cross track vs. A long track models

Image 2.6.2 Stereo model of line sensor imagery

Image 2.6.3 IKONOS-Aerial camera

Image 2.6.4 Relative Orientation : Absolute Orientation

Accuracy evaluation of satellite stereo images is a fundamental Mile Stone for photogrammetry, to contribute many applicable fields with high 3D measuring accuracy and efficiency. For this purpose, by courtesy of Space Imaging Japan and Digital Globe Japan, World View2 images on Nov. 11th 2015 of Kyoto University Campuses area were presented to us. Next figure shows us satellite image and 3D Image map ( map image on AutoCAD coordinate system). Concretely speaking, we aimed to set up non- parallax stereo model and ground accuracy evaluation using Ground Control Points, which have the accuracy of 1cm in the ground reference coordinate system.

Image 2.7 Kyoto University area WorldView2 image and GCPs distribution( planned )

3. Kyoto University campus experiment of WorldView2 stereo model on methodological research and accuracy evaluation

First, technical specification for public surveying is overviewed, as practical quality control issues and accuracy requirements, for further applications. In 2012, we described a draft, Shinshu University 3D Image Map Archiving manual, and succeeded in the world’s first aerial triangulation and ortho-mosaic production from antique aerial photographs of Shinshu in 1940’s taken by USAF. Based on the achievement, we referred to the official specification of the Ministry of Land, Infrastructure, Transport and Tourism, and found the following critical problems; (1) Gist of aerial photogrammetry:Ch.3;Sec.1;Arti.106: Results include neither 3D image models nor 3D image maps. (2) Digital image used: Arti.257: Historical aerial photos are underestimated, and the state of the art technology, digital stereo plotter is also undervalued. (3) Aerial Triangulation: Sec.8; Arti.165: Accuracy measures of unknowns, like exterior orientation parameters and tie point coordinates, in adjustment are not used for 3D image modeling. (4) Single point surveying method: Sec.3, GCP’s setting; Arti.112: Parameter Estimation approach, like FKP satellite surveying, is not explicitly designated as a standard satellite surveying. Instead, Interferometric approach is assigned as a compulsory approach without theoretical explanation. (5) Rigorous map projections on 3D-CAD/GIS systems are not well applied as practical technical solution, so results of surveying are not well suited for Construction Information Management/Modeling initiative of Ministry of Land, Infrastructure, Transport and Tourism ( MLIT for short) . (6) Satellite 3D image modeling are neither evaluated nor prescribed. Based on the above mentioned situations, aiming at the applications for 2011 disaster reconstruction projects, we prepared the following working manuals as specifications. These specifications are to be authorized by the official article of Cadastral Survey Standard Specification of MLIT.

(1) Cadastral Survey Ground surveying method (2) Cadastral Survey Aerial Surveying method (3) Cadastral Survey High Precision Aerial Surveying method (4) 3D Image Map Archive Production

After unsatisfactory responses of Geographical Survey Institute for a few years, referring to Survey Act: Arti. 56; Advice of Minister of Land, Infrastructure, Transport and Tourism:, as a surveying enterprise owner, I requested three times revision of official surveying specification, indicating solutions for the problems after the 2011 disaster and volcanic eruption occurrences. In such cases, I presented the practical system of 3D image measuring system at responsible offices. In general, I have criticized the current official surveying specification, and showed the alternative solutions. Now it would be the time to organize the accuracy evaluation experiment, corresponding with our own proposal of “ National Land Survey Act” based cadastral survey specification: cadastral surveying working manuals. Especially for forestry cadastral survey, satellite imagery based aerial surveying method is now added for the existing working manuals, to accelerate vast extent of forestry area of Japan, using satellite imagery. This is our initial background of the satellite imagery experiment.

To catch up with the status of technological developments in the world since 1999, especially the latest achievement of Prof. Dr. Clive Fraser of University of Melbourne, Australia was introduced with 3D image models and presented papers. Hobart model in Tasmanian island, Australia is covered by Geo Eye1 satellite images taken in 2005. The accuracy evaluation is reported to American Society for Photogrammetry and Remote Sensing, and described in monthly publication ( Nov. 2009). As we have already modelled on Summit Evolution photogrammetric system with AutoCAD; Civil3D, as mapping object, we proceeded to evaluate the accuracy and methodology of Prof. Dr. Fraser. According to the above achievement and ASPRS specification, we made a draft of “ Cadastral Survey Satellite Imagery Aerial Surveying method” in 2015.

15 3.1 Generation of manual “Cadastral Survey Satellite Imagery Aerial Surveying method”

Referring to “ Cadastral Survey Standard Specification: rev. 2010.10.12 Ministerial Ordinance No. 48) and related guidelines, we could make up the manual “Cadastral Survey Satellite Imagery Aerial Surveying method”, corresponding to Ground Surveying and Aerial Surveying; Ch.4 Cadastral Surveying:, and based on article no. 8, this manual could be practicable after the approval of the minister of land, infrastructure, transport and tourism.

3.2 Accuracy requirement for aerial surveying ground control points

Cadastral Surveying Aerial Surveying method in Cadastral Survey Standard Specification allows Single Ground Control surveying based on fundamental triangular point as a standard procedure for land-parcel surveying. Comparing with German cadastral survey specification, which describes and rules the standard deviation of ground controls within 2cm, reference controls within 4cm in practice. Expensive land prices have shown big discrepancies of point coordinates in the urban area. For rural and forestry areas, we could apply photogrammetric 3D image models to extract satisfactory accuracy for photogrammetric ground controls, even with old aerial photos in digital stereo plotters. In comparison with the accuracy criteria of Cadastral Survey Standard Specification, we could prepare for photogrammetric ground controls, using accuracy levels of helicopter photogrammetry, high resolution satellite 3D image modeling and historical aerial photogrammetry. Not only ground controls but also boundary lines and cadastral features are accurately measured by photogrammetry. Accuracy of forest boundaries is estimated by the accuracy measures of aerial triangulation, like standard deviation of unit weight （σ0）and unknowns, representing measuring accuracy of distinct object point on 3D image model.

Table 3.1 Accuracy classification ( Cadastral Survey Standard Specification)

Tested satellite 3D stereo model has a pixel size of 50cm on the ground, and trajectory height;770km,focal length of line scanner lens; 13m, then the image scale is about 1/60,000, which is similar to the ordinary aerial photo scale for 1/25,000 photogrammetric mapping with old fashioned plotters and mapping procedures. As we now have precise photogrammetric 3D measuring system like Summit Evolution, we could realize more larger map scale mapping, like 1/5,000 or more. To ensure the positioning accuracy, we need more precise ground control surveying system in real time mode. Comparing with the ground pixel size,50cm, of satellite imagery, we need ground control points of accuracy level, 1-3cm on the ground. This was accomplished by parameter estimation satellite surveying, FKP( Flaechen Korrktur Parameter in German) approach in a few days. The coordinate system and geodetic datum applied were decimal Latitude-Longitude-Orthometric Height pseudo rectangular coordinate system and WGS84 geodetic datum.

3.3 FKP satellite surveying of ground controls: Overview FKP satellite surveying classified in parameter estimation approach in geodesy is a fundamental technology for land-parcel surveying, called Single control surveying in cadastral surveying ground surveying method, and surveyed 15 ground control points for the experiment. The advantage of this technology is to adjust every second a geodetic network with fundamental triangular controls: Electronic Control Points and new observation points together, ensuring the accuracy of 1cm on the ground. The process has 2 steps, at first error parameters are estimated at fundamental triangular controls, then error correction parameters of geodetic network area are transferred to new observation points to be adjusted with observations at site. As 2 step network adjustments are conducted with parameter estimation approach, the 3D vectors from geo-center are adjusted by least square method, referring to the satellite emission center along the satellite locus. This approach is so rigorous and flexible that different frequencies of positioning satellites are induced into 3D-distances from the satellites and receivers. This approach is called also non-differenced approach, comparing with interferometric ( double differenced ) approach, which gives severe environmental restrictions, such as tall buildings and forest canopies. As FKP satellite surveying could adjust every second the geodetic network, to provide adjusted coordinates and standard deviation, monitoring of geological faults and volcanic expansion could be detected after 1 second of data

16 receiving, and with accuracy of 1cm on the ground.

Image 3.2 FKPsatellite surveying (schema): RTK’s error propagation and FKP’s effect

For Kyoto University Area experiment, FKP satellite surveying has provided evenly distributed ground controls with high accurate coordinates. Next figures show the whole image area and enlarged large scale image. For positioning of FKP ground control points, distinct marks in an image were approximately selected on relatively oriented 3D stereo model without parallaxes. Then at site signalized point was surveyed with FKP surveying procedures. The final results were summarized straightforward from 3 sets of real time adjustment at the point.

Image 3.3.1 Enlarged image (Center for South East Asian Studies: Kyoto Univ. on Summit Evolution )

Image 3.3.2 Ground Control Point 1618: Near CSEAS: Kyoto Univ.; Kojin-bashi bridge

17 3.4 Results of GCP- FKP satellite surveying

As FKP satellite surveying conducts real time geodetic network adjustment, at site more than dual frequency receiver, antenna-tripod and communication-adjustment note PC are necessary outlets. At first available satellites and visibility in the sky are checked, and GNSS data and FKP correction parameters are transmitted to PC, then geodetic network adjustment is done every second, showing the averaged coordinates and standard deviations. These data sets are stored in PC as the results of adjustment based on parameter estimation approach, for accuracy evaluation and quality control.

As for accuracy management and quality controls, interior errors of accuracy measures and exterior errors from discrepancies of distances between coordinate differences and TS observed range are employed. These contents are described as follows;

(1) Selection of ground control points Based on satellite image area map, well evenly distributed spots were selected before FKP satellite surveying at site. Image Map of satellite image was oriented in Longitude-Latitude-Orthometric Height coordinate system, estimating traffic conditions and setting up situations, then candidate locations for distinct points were selected.

Image 3.4 KyotoCity-25K--WorldView2-LL84- satellite image area and GCP ( candidates )

18 (2) FKP satellite surveying FKP satellite surveying was started in front of Kyoto City hall crossing. Next figure shows the situation during the measurement of 30 minutes.

Image 3.5 FKP satellite surveying：Kyoto City Hall； GCP No.1627 Surveying registration book could be produced from the following table, as official result.

Image 3.6 FKP satellite surveying registration table ( accuracy report)

19 GCPs ( 14 points ) are summarized in this format, as official registration book. (ref.：「 20160214-0216FKP 衛星測量成果表.pdf」) Ground Control Points were used as Orientation Control Points in absolute orientation, to form 3D image model and to evaluate the accuracy of the satellite 3D stereo image model.

Image 3.7 GCP plotted point map ( Adjusted coordinates on 3D-CAD)

(3) Results of GCPs and evaluation GCP accuracies by FKP satellite surveying are evaluated by the following accuracy measures. (3.1) 3 set adjustments( averages and standard deviation)： Their averages are（6mm、4mm、12mm）and their standard deviations are(4mm､4mm､10mm) Table 3.1 FKP satellite surveying; 2016.02.14-02.16：Accuracy Evaluation

(3.2) Residual’s standard deviation at average computation (⊿xmm、⊿ymm、⊿hmm) In situations ;GDOP’s average3.3,their standard deviation 1.3, then average（0.9mm,1.1mm,2.3mm）,their standard deviation (0.2mm,0.1mm,0.6mm). Standard deviation values are much more improved than the period when coordinates of Electronic Control Points were turbulent by some sources and had the values of 10mm for standard deviation. Comparing with the tolerance within 5mm(planimetry) ; 8mm(height) and results of German geodetic network adjustment, and nationwide adjustments by the author in 2013-2015, ECPs may have the standard deviation of a few cms.

(3.3) The number of available satellites( currently only GPS satellites）； This is an auxiliary index, but mean of average number of satellites was 7.3 satellites, and the standard deviation was 1.4 satellites. In this sense, multi-GNSS satellites ( GPS, GLONASS, Galileo, QZSS and Compass) could be used in parameter estimation approach as fundamental observations in the adjustment, and the author tested in 2012 GPS-GLONASS-QZSS combination successfully. On the other hand, interferometric approach in Japan has not yet used simultaneously such a combination, and initialization has some problems related to this reason.

(3.4) Fixing time； This is an auxiliary index, but average fixing time was 2.1 minutes, and the standard deviation was 0.7 minutes. Among real time networking RTK satellite surveying approaches, deterioration of results in quality occurred so often, because of this promotion of fixing time. ”Interferometric = Base-line; Double difference approach could not solve altitude-angle, multi-path, ionospheric issues correctly for quality control of results. This situation is one of the reasons why real time networking satellite surveying is not so popular in Japan. In Kyoto University experiment 2016, VRS method of Interferometric approach showed initialization errors beside successful FKP measurement. On the other hand, parameter estimation approach = FKP satellite surveying has always shown not only the efficiency of fixing time but also reliability of results even in urban area and forest area. And checking process by authorization organization requests rather old fashioned booking procedures to utilize the results. As described before, FKP satellite surveying is able to summarize the results at site with complete accuracy measures.

(3.5) Methodological research on ”Interferometric = Base-line; Double difference approach” For more than 2 decades, ”Interferometric = Base-line; Double difference approach” was not explained by authentic reference books, and there are few conceptual definitions and accuracy measures for this approach. For Cadastral Survey Standard Specification, there are many restrictions such as altitude angle, multipath effect and multi-GNSS combination out of ”Interferometric = Base-line; Double difference approach”. This might be the major barrier of National Land Survey projects, especially for forestry cadastral survey and urban redevelopment projects. In National Land Survey Projects, Kyoto prefecture and city are the most backward municipalities in Japan.

(3.6) Proposed aerial surveying, high precision aerial surveying and satellite imagery aerial surveying for promotion of national land survey projects The author wrote the drafts of the following applications; (1) Cadastral Survey ground surveying manual: FKP satellite surveying (2) Cadastral Survey aerial surveying manual: aerial photos from 1940’s (3) Cadastral Survey high precision aerial surveying manual: Helicopter photogrammetry Now it is time to add one more manual for vast remaining area of forest and urban area in Japan. Cadastral survey itself is not only boundary determination projects but also national land administration system, which means German GISe (GeoInformationsSysteme). Japan has its own missions for National Land Resilience Act and Plan, starting from 2015. During our development of 4D Image Map Archive Designed Aerial Survey in Center for South East Asian Studies, we have made potential supports to south east Asian students, and UN-GGRF( Global Geodetic Reference Frame) initiative would revise the maps of those countries for the future infrastructural environment.

21 4. Satellite Imagery 3D stereo modeling and accuracy evaluation

Satellite Imagery 3D stereo modeling is now realized by RPC(Rational-Parameter-Coefficient) method.3D stereo Image model is also combined in motion with 3D-CAD system for 3D topographic mapping and terrain data mensuration. This kind of actual system is applied on DATEM : Summit Evolution 3D image model mensuration system( Digital stereo plotter). The image processing and modeling are shown in the following figure.

Image 4.1 Satellite imagery 3D stereo modeling and mensuration

Image 4.2 Summit Evolution: Initial screen and３D-CAD add-on software

22 4.1 Satellite stereo imagery files and RPC orientation files：Project definition Summit Evolution is a world standard photogrammetric 3D image modeling/mensuration system which is widely used in mapping organizations in the world, with 3D-CAD and GIS systems. Especially for 3D mapping, 3D-CAD system : AutoCAD and extended 3D designing and animation modules support for worldwide ISO standardization and BIM( Building Information Modeling) initiative. Standard 3D drawing files : DXF and DWG are commonly used in other CAD/GIS software. The world’s first combination with 3D mapping stereo plotters was established in 1990s. The whole procedures are started with Project Definition, and measurable image files（Pyramid type TIF or JPG files）and orientation file, so called RPC（Rational Parameter Coefficient）file, which was derived from transformation parameters from image to relatively oriented model coordinates, are introduced to form 3D image model. Currently ,this RPC files are provided by Digital Globe, to put stereo images in 3D coordinate system ( pre relative orientation stage).Summit Evolution could accept other satellite stereo imagery, such as SAR（Synthetic Aperture Radar）、 LIDAR（Light Detection And Ranging）,as well as Terrestrial Laser Scanning or UAV(Unmanned Aviation Vehicle)

Image 4.3 Summit 3D stereo model from several stereo model sources and RPC files

4.2 RPC orientation stereo modeling ( single orientation model)：Model definition

3D stereo model with RPC orientation files is configured with 2 images from different sights. 2 images are combined from 3 line sensors which have forward – nadir – backward sight scanner. Such combination is shown as stereo 3D image model to be observed in stereo scope. Those images are superimposed with 3D vector lines from 3D-CAD screen. As an essential requirement, 3D stereo model should not have serious parallaxes in stereoscopic environment. Then relatively oriented 3D stereo model is now to be oriented into reference ground coordinate system.

Image 4.4 Summit satellite imagery stereo model screen and relatively oriented stereo 3D image model

This kind of stereo 3D image model could be related with Bing Map or Google Map, in a similarwayto3D-CAD drawing screen, via reference ground coordinate system.

Image 4.5 Summit satellite imagery stereo 3D model related with Bing Map and Google Map

4.3 Tie Point based relatively oriented ( parallax corrected ) modeling：Tie Point Measurement

Pre relative orientation 3D image model with only RPC orientation files might have parallaxes in x and y directions during stereoscopic observation. To correct parallaxes in the model, Tie Point Measurement should be conducted. Tie point measurement could adjust the residuals of 3D model, by using least square adjustment process. There might be simultaneous solutions involving RPC files for parallax-free 3D model.

Image 4.6 Summit satellite imagery stereo 3D image model with Tie Point residuals

The following figures are comparing with each other to show initial parallaxes from RPC orientation files(left) and adjusted residual 3D model (right).

Image 4.7 RPC orientation file model(L) and Tie point adjusted 3D image model(R)

4.4 Absolute orientation 3 D image modeling( Spatial similarity transformation)：Absolute Orientation

Tie point adjusted 3D image model could be used to check coordinate discrepancies between relatively oriented model points and ground control point, using stereoscopic measurement on each ground control point. This process is called as absolute orientation of photogrammetric basis, using spatial similarity transformation, and central projection camera images follows this process as an authentic procedure. On the other hand, satellite imagery has stereo 3D image model derived from line sensor driven belt-like imagery, and the characteristics appear at this absolute orientation process as discrepancies of coordinates. The factors of discrepancies might be caused by pseudo rectangular coordinate system ,since the relatively oriented 3D model is constructed in 3D rectangular coordinate system. For this time, we suspend this issue for a while, since the area is relatively small enough : 2km x 3km.

Image 4.8 Discrepancies of Ground Control Points on relatively oriented 3D image model

4.5 Distribution of discrepancies of Ground Control Points ( Accuracy evaluation)

Ground Control Points have the coordinates on Geocentric coordinate system ( WGS84) which has the origin at gravity center of the earth, after real time geodetic network adjustment at site. Then identical latitude-longitude-ellipsoidal height coordinates are converted, and modified into pseudo 3D coordinate system which has latitude-longitude-orthometric height coordinates in Summit Evolution 3D modeling / mensuration environment. In this process, we could detect the coordinate discrepancies of relative oriented modeling and ground FKP satellite surveying, as shown in the following table. Table 4.1 Coordinate discrepancies between Relative oriented Modeling and ground FKP satellite surveying

Here we can find out the amount of discrepancies, as the unit is decimal degree which shows the distance of about 100km, average values of discrepancies are : longitude：-30cm、latitude：160cm、orthometric height：330cm, and standard deviations are longitude：30cm、latitude：90cm、orthometric height：35cm. These are approximate accuracies. According to discrepancy distribution of relative oriented model,we could estimate rule of thumb guide line for accuracy of the model. Adequacy and validity of spatial similarity transformation could be further considered with image scale , pixel size and ratio of trajectory height/ image interval. Here we refer to Digital Globe’s technical specification on World View2 satellite, and summarize the current status and future feasibility.

Image 4.9 Digital Globe _ WorldView2 satellite technical specification

According to this technical specification, satellite trajectory height: 770km、ground resolution under nadir sight:46cm, and estimated lens focal length:15m, image scale might be about 1/50,000 and pixel size : 10μm. This relationship is similar to aerial camera used in aerial triangulation. Therefore if we assume that measuring accuracy on image surface could be half a pixel, accuracy level is also similar to the achievements of late Dr. Atsushi Okamoto with his simulation and Kobe/ Mt. Fuji experiments, which means that accuracy level of 25cm could be acquired in practice. Now we proceed to investigate the accuracy of absolute orientation, dealing with the following items; (1) Comparison between different 3D rectangular coordinate systems Satellite imagery 3D stereo model: origin, 3 axes; arbitrary selection Ground control points ( at site ): origin, 3 axes; WGS84 geodetic datum Ground control points ( Summit/Civil3D ): origin, 3 axes; pseudo 3D rectangular axes (2) Extension of absolute orientation methods

: Spatial similarity transformation as fundamental equation of photogrammetry : 3D affine transformation of deformed 3D image model for absolute orientation (3) Evaluation of RPC approach as relatively oriented 3D image modeling

26 : RPC parameter coefficients, image surface and trajectory elements (4) Upgrading performance of line sensor optics : high resolution pixel ,CMOS elements and effective image data compression (5) Windowing and archiving of satellite belt-like imagery Through these improvements, 3D image models out of satellite imagery would replace aerial photography in well established mapping technology. Satellite 3D image modeling and remote sensing technology would be merged into 3D stereo image modeling, mensuration and analysis for earth mensuration technology.

5. Considerations and Discussions

As we could realize the accuracy on the ground of satellite imagery 3D stereo models corresponding with Official Surveying Specification and Cadastral Survey Standard Specification, we are to summarize technical components for practice into specification of “ Satellite imagery based aerial survey method“. For this process, we could now point out feasibilities and subjects of satellite imagery based aerial survey method, referring to many developments, achievement and current accuracy evaluation projects.

5.1 Requirements for ground control points in satellite imagery based aerial survey method

To transform the coordinates of satellite imagery 3D stereo model into 3D reference ground coordinate system, considering that gravity center origin coordinate system is 3D rectangular coordinate system, it is worth investigating that the coordinate system of map projections used in absolute orientation of satellite imagery 3D stereo model is pseudo rectangular 3D coordinate system.

Image 5.1 Geocentric Coordinate System and CAD-Globe- UTM-TM map projections

The relationship in spatial similarity transformation between earth ellipsoids and geoid model between ellipsoidal height and orthometric height should be rigorously defined at accuracy evaluation.

Image5.2 2 earth ellipsoids and geophysical earth: 3 Globes-Coordinates-Model and Geoidal Height

Based on these premises, for this experiment, we used latitude-longitude-orthometric height – pseudo 3D rectangular coordinate system for accuracy evaluation. The research area was west-east;2km, north-south;3km, then effects of earth curvature, difference between 3D image surface and pseudo horizontal plane of the area were considered as follows;

Image 5.3 Height difference between 3D image model on CAD-Globe and map projected pseudo plane

As satellite 3D stereo model is physically formed in 3D rectangular coordinate system, for accuracy evaluation, we have to think about map projections. And since our fundamental issue in photogrammetry for satellite imagery 3D stereo modeling is the mathematical model on absolute orientation、we have to create an advanced 3D image modeling, comparing with spatial similarity transformation of centrally projected imagery.

5.2 More precise and high resolution satellite imagery 3D stereo model

High resolution ( precision) satellite imagery and 3 sight line scanners along the track have made 3D stereo image model, which is comparable to aerial camera image model, a real measurable object in many earth sciences. Wide swath and high frequency could replace aerial camera photography, which is characterized with multiple flight lines and over and side lapping film/digital imaging. After this experiment for 3D image modeling and accuracy evaluation, we could set up technical guide lines for practice, and organize production lines for national land information system. Along this direction, scientific and technological paradigm of remote sensing, which has supported earth sciences with precise images, image analysis and spatial analysis, would include satellite imagery 3D stereo models. Now we could set up our subjects for this direction.

(1) Refinement of mathematical model for satellite imagery 3D stereo modeling :satellite imagery based aerial survey (2) 3D-CAD mensuration technology on CAD-Globe, infrastructure designing and landscape based area studies (3) 3D digital archiving of satellite imagery 3D stereo models

5.3 4D Image Map Archiving

As satellite imagery 3D stereo modeling and digital archiving are to be constructed with 3D image maps, which are measurable on 3D-CAD system, 3D image models at image acquisition represent Historical Reality as essential nature. Therefore we propose 4D Image Map Archive, which combines existing maps, aerial photos, digital terrain models and satellite imagery into 3D global coordinate system. For this archiving, aerial photo images and satellite imagery are mostly used as sources, then we named this technology as 4D- Image Map Archive Designed Aerial Survey、4D-IMADAS for short), and we have started our practice.

5.3 Contribution of 3D-CAD for BIM/CIM initiatives

In 2015, National Land Resilience Act was in force against natural and artificial disasters such as earthquakes occurring directly beneath the Tokyo Metropolitan Area, Nankai Trough earthquake/ tsunami, Sakurajima volcanic eruption, typhoon flooding and radioactive accident, and the ministry of land, infrastructure, transport and tourism is now promoting so called BIM(Building Information Management) or CIM(Construction Information Modeling/Management) initiatives. In this process in the world, the United Nations resolved UN-GGRF（Global Geodetic Reference Frame） initiative in 2014. The author reported Japan Geodetic Datum 2000 initiative in surveying/mapping business group, and is quite ready for contributing for Asian countries, working with BIM/CIM initiatives, by setting up technological basis on 4D-IMADAS concept.

28 Summary:

Since East Japan earthquake in 2011, the author has been developing parameter estimation satellite surveying and 4D Image Map Archive approach. Starting from forest boundary cadastral survey with GPS-FKP satellite surveying, Parameter Estimation Gnss Assisted SUrveying System ( PEGASUS for short ) has now evolved to multi-GNSS satellite surveying and geodetic network adjustment. Parameter Estimation approach in geodesy is now the basis of National Land Information System ( GeoInformationsSysteme: GISe ; in German) with 3D cadastral system, which corresponds with “National Land Survey Act” for land classification, water resource investigation and cadastral survey. For many decades, Official Surveying Standard Specification has shown out of date rules and regulations against disasters on fragile national land and crustal shift, and should be revised with updated and advanced technologies. This Kyoto University area satellite imagery 3D modeling has shown many possibilities for solving critical issues of land administration, environmental change and ecological conservation. This paper has been prepared with the help of a working group in Kyoto University, Center for South East Asian Studies. We acknowledge the help of Space Imaging Japan and Digital Globe Japan, who have provided precious satellite images with RPC orientation files. We particularly like to thank DATEM systems international for their encouragement and operational supports and comments.