Heliosat3 WP4010 D13.1 Geolocation

Project title:

Project Acronym:

Project No.:

Energy-Specific Solar Radiation Data from Meteosat Second Generation (MSG):The Heliosat-3 Project

NNE5-2000-00413

Title:

Main Author:

HELIOSAT-3

Geolocation of high resolution data of Meteosat-8 (VCS-XPIF format)

R. Kuhlemann (Oldenburg University)

Contract No.: NNK5-CT-2000-00322

Date: June 2005

Contributing Author: A. Hammer, A. Drews (Oldenburg University)

Deliverable: D 13.1

Preface

The work presented in this report is part of the deliverable D13.1 for theEuropean research project Heliosat-3. It belongs to workpackage 4010 (solarenergy processing chain). The Heliosat-3 project is supported by the fifth frame-work program of the European Commission under contract number NNK5-CT-2000-00322.

Geolocationof high resolution data of Meteosat-8

(VCS-XPIF format)

Rolf Kuhlemann, Anja Drews, and Annette Hammer

20.6.2005

Outline:

• Introduction

• Interpretation of IDRISI-maps

• Investigating HRV data

• General information about provided data and programs

• Results

• Appendix (Images)

Introduction

The match between certain pixels with their line and column within a satellitemeasured image and geographical positions with their latitude and longitude iscalled geolocation. Informations about resolution, distances to the equator (line-and column-offset), and other image properties are given within the headers oftransmitted images.For validation purposes and operational use it is necessary to check and improvethe geolocation of Meteosat-8 data. Both, the high resolution broadband channel(HRV) and a representative low resolution channel around 800 nm have been in-vestigated. With helpful assistance of Anja Drews it has been possible to use theGIS software IDRISI Kilimanjaro to check the match between the geolocationof HRV/VIS008 images according to their header informations on one side andcoast line/country boarder maps within IDRISI on the other side. These coastline maps are provided by the ESRI corporation (ArcView - Europe shape files).Furthermore, Antonio Ortegon Gallego (ITC) provided similar maps of the Ca-nary Islands for the same purpose.The computational format of the processed data is not the original HRIT formattransmitted by EUMETSAT, but the synthetic XPIF format generated by thesoftware of the receiving system of the company VCS installed in Oldenburg (seewww.vcs.de).All investigations were done by using reference albedo maps of Europe and theCanary Islands for June (12:00 slot (UTC)) derived with the Heliosat-1 proce-dure within the new program Sunsat (see Kuhlemann et al.: Sunsat - the newprogram for processing high resolution data of Meteosat-8).

Interpretation of IDRISI-maps

To interpret the figures at the end of this report further information are necessary.The pixels on the projected maps are not (!) the pixels of the original images.They are arbitrarily choosen and have everywhere the same size. Sometimes,especially near the poles, IDRISI is not able to fill all pixels reasonably, becauseno Meteosat-8 pixel matches latitude and longitude in the map. These pixelshave values of zero. The interpolation of these values would have been possible,but it is not necessary for coast line comparisons. The coloring of the calculatedmaps is different, because some were calculated for the whole of Europe, othersonly for the regions of interest in order to accelerate the necessary calculations.Therefore, colors should be ignored, only contours are of interest. The whitelines denote the country lines and the bigger cities and/or sites of measurement(Canary Islands) are marked with red circles.

Investigating HRV data

The first step was, to test the geolocation of low resolution VIS008 data (VCS-XPIF-format) in order to check the quality of the geolocation. As size of a

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pixel the value reportet by Marion Schroedter-Homscheidt and Lucien Wald hasbeen used (17.832◦ aperture angle / 3712 pixels). For comparison, coast lines inSouthwestern Ireland, the region of Bergen, South Portugal, the Balearic Islands,some Greek Islands, and the Baltic Sea in Northern Germany have been takeninto account. The results are presented in the figures on page 10 and 11. Thesampling of the data with the country line map of IDRISI is excellent for thislevel of resolution.The same procedure as used for VIS008 data was adopted to HRV data (VCS-XPIF-format) and revealed distortions. This was done by using header informa-tions of the VCS-XPIFdata and the dimensions of the full disc image (17.832◦

equal 11136 pixels; line-offset = 5568; column-offset = 2028). A simple back shiftof the images by changing column and line numbers did not solve this problem.The distortions have been even larger with the corrected line-offset (5566), re-ported by Marion Schroedeter-Homscheidt as information from the MSG/RAOworkshop in Salzburg (September 2004) for images before the 2.9.2004.A test series of changed line- and column-offsets revealed, that the best match forWestern Europe occures, if the line-offset equals 5572 and the column-offset 2029.The quality of this correction decreases with growing distance to the Greenwich-Meridian or nearby. While the found geolocation is really good for Bergen, theBaltic Sea (Fehmarn), the Balearic Islands and Portugal (pages 12-15), this is nottrue for Southwestern Ireland and the Greek Islands (pages 16-17). For South-western Ireland a column-offset of 2030 has given a better match, for the GreekIslands one of 2027.

XPIF-HRV-Europe HRIT-HRV (full-disc) subset

Location Country latitude longitude col lin l-off ad-l-off c-off ad-c-off size

Bergen Norway 60.4 N 5.32 E 1164 289 5572 +6 2029 +1 21 * 21

Freiburg Germany 48.018 N 7.836 E 1448 900 5572 +6 2029 +1 21 * 21

Geneve Switzerland 46.2 N 6.1 E 1346 1006 5572 +6 2029 +1 41 * 41

Vaulx-en-Velin France 45.78 N 4.92 E 1259 1030 5572 +6 2029 +1 11 * 11

Nantes France 47.15 N 1.33 W 801 945 5572 +6 2029 +1 21 * 21

Barcelona Spain 41.386 N 2.118 W 1066 1329 5572 +6 2029 +1 11 * 11

Bratislava Slowakia 48.17 N 17.08 E 2072 905 5572 +6 2028 +0 21 * 21

Thission Greece 37.973 N 23.718 E 2822 1623 5572 +6 2027 -1 21 * 21

Penteli Greece 38.049 N 23.863 E 2833 1618 5572 +6 2027 -1 21 * 21

Table 1: Geolocation of HRV data of different sites in Europe. Beside latitude/longitude of a

certain place the corresponding column and line in VCS-XPIF data of Europe are given, alto-

gether with the necessary additional line- and column-offsets. The according subset dimension

is given also.

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Table 1 contains all site informations including additional line- and column-offsetsfor geolocation and therefore validation of calculated data. All of the values arederived from the VCS-XPIF data for Europe, which are stored in Oldenburg(header informations: columns = 3072, lines = 1800, line-offset = 5318, column-offset = 895, resolution = 222). These values determine the region on the earthdisc and correspond therefore to its dimension (columns = 11136, lines = 11136,line-offset = 5566 (5568 before 2nd of september 2004), column-offset = 2028,resolution = 222).Latitude and longitude (nearly) determine a pixel with column and line in theHRV data of Europe (VCS-XPIF- format).Altogether with the transmitted values for (already corrected) column-offsets andline-offsets the necessary additional column- and line-offsets as found for propergeolocation are presented in Table 1. Finally the dimension of the subsets aroundsites of measurement is given. The particular place of the instrument should bein the middle.The same procedure has been done for the Canary Islands (Table 3). It has beennecessary to give the additional line-offset a decimal character. Table 3 resumesall informations one needs to validate with sites of measurement on these Islands(red dots, page 21). Accurate determination of latitude and longitude of themeasuring sites on the Canary Islands has been done and provided by AntonioOrtegon Gallego.Because of the small size of the Canary Islands, each subset contains a wholeIsland (pages 18-20). To reconstruct the location of each Island within the VCS-XPIF data of the whole Canary Islands, it is possible to take their header in-formations (line-offset: 3080, column-offset: 1800) and the following values forhorizontal and vertical offsets, which are used to generate the subsets for eachisland (Table 2).

Island horizontal offset vertical offset

Lanzarote 493 57

Fuerte Ventura 424 116

Gran Canaria 299 169

Gomera 168 173

Teneriffa 210 137

La Palma 120 115

Hierro 88 208

Table 2: Horizontal and vertical offsets of the Island subsets within the VCS-XPIF data of all

Canary Islands.

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subset-loc HRIT-HRV (full-disc) subset

Island site latitude longitude col lin l-off ad-l-off c-off ad-c-off size height [m]

Gran Canaria C0 27.8175 N 15.4244 W 42 43 5570.5 +4.5 2030 +2 55 * 56 47

Gran Canaria C1 28.1108 N 15.4169 W 47 16 5570.5 +4.5 2030 +2 55 * 56 17

Gran Canaria C2 27.9901 N 15.7907 W 11 28 5570.5 +4.5 2030 +2 55 * 56 197

Gran Canaria C3 27.7700 N 15.5600 W 29 47 5570.5 +4.5 2030 +2 55 * 56 187

Gran Canaria C4 27.7716 N 15.5841 W 27 47 5570.5 +4.5 2030 +2 55 * 56 265

Gran Canaria C5 28.0337 N 15.4991 W 38 23 5570.5 +4.5 2030 +2 55 * 56 525

Gran Canaria C6 27.8839 N 15.7216 W 16 37 5570.5 +4.5 2030 +2 55 * 56 300

Gran Canaria C7 28.1681 N 15.6865 W 23 11 5570.5 +4.5 2030 +2 55 * 56 40

(Gran Canaria)* C7 28.1554 N 15.6930 W 23 12 5570.5 +4.5 2030 +2 55 * 56 65

Fuerte Ventura F1 28.4248 N 14.0579 W 51 37 5570.5 +4.5 2030 +2 83 * 75 450



(Fuerte Ventura)** F3 28.6856 N 14.0116 W 59 14 5570.5 +4.5 2030 +2 83 * 75 11

Gomera G1 28.0917 N 17.1107 W 25 18 5570.5 +4.5 2031 +3 31 * 27 91

Gomera G2 28.0998 N 17.3452 W 5 17 5570.5 +4.5 2031 +3 31 * 27 35

Hierro H1 27.8123 N 17.9161 W 28 10 5570.5 +4.5 2031 +3 37 * 29 221

Hierro H2 27.6401 N 17.9785 W 20 26 5570.5 +4.5 2031 +3 37 * 29 93

Lanzarote L1 28.8884 N 13.8344 W 9 54 5570.5 +4.5 2030 +2 57 * 61 5

Lanzarote L2 29.0981 N 13.5083 W 42 35 5570.5 +4.5 2030 +2 57 * 61 47

La Palma P1 28.6860 N 17.7644 W 25 22 5570.5 +4.5 2031 +3 35 * 46 21

Teneriffa T0 28.4931 N 16.3246 W 61 15 5570.5 +4.5 2031 +3 85 * 63 562

Teneriffa T1 28.4137 N 16.5545 W 39 21 5570.5 +4.5 2031 +3 85 * 63 19

Teneriffa T2 28.2383 N 16.8405 W 10 40 5570.5 +4.5 2031 +3 85 * 63 971

Teneriffa T3 28.0703 N 16.5542 W 33 54 5570.5 +4.5 2031 +3 85 * 63 545

Teneriffa (Teide) TD 28.3000 N 16.5097 W 41 33 5570.5 +4.5 2031 +3 85 * 63 2398

Table 3: Geolocation of different sites on the Canary Islands in HRV data. Beside lati-

tude/longitude of a certain place the corresponding column and line in the VCS-XPIF data of

the Canary Islands are given, altogether with the necessary additional line- and column-offsets.

The according subset dimension is also given. For identifying measurement sites (row 2) look

also on maps on pages 18-20. (* C7 future location,** F3 after the 29. of September 2004)

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General information about provided data and programs

To avoid a mix of uncorrected and modified images, by means of their headerinformations, the correction works locally in our programs. All headers of theVCS-XPIF images contain the old, “wrong” numbers for line- and column-offset.With the proper geolocation generated here, it is possible locate accurately eachpixel in VCS-XPIF data. This is done for all pixels and all provided subsets.These data are provided in the files named latlong-location.dat on the server(internal Heliosat-3 pages).To work with modified offsets, the program Sunsat (see Kuhlemann et al.: Sunsat- the new program for processing high resolution data of Meteosat-8) has beenchanged in the way that there are optional parameters for additional line- andcolumn-offsets. Altogether with the lists of the found values for additional line-and column-offsets (Table 1+3) accurate processing is possible.

Results

A detailed geolocation of many places in Europe and on the Canary Islands re-vealed, that low resolution data of Meteosat-8 in VCS-XPIF format are geolo-cated properly in terms of their header informations. Unlike this, high resolutiondata are distorted. With local manipulations of the line- and column-offsets itwas possilbe to compensate this effect and therefore an accurate usage of VCS-XPIF data.A geolocation of the original high resolution HRIT data transmitted by EU-METSAT revealed, that these data are undistorted. It seems, that the observeddistortions in high resolution data are caused by failures of the software of theVCS company. Therefore, it is planned to switch the processing chain fromVCS-XPIF data to HRIT data.

Appendix (Images)

• S. 10: Geolocation of VCS-VIS008 data with subsets of Norway, BalearicIslands, and Greek Islands

• S. 11: Geolocation of VCS-VIS008 data with subsets of Western Irland,Fehmarn, and Portugal

• S. 12: Geolocation of VCS-HRV data with subsets of Balearic Islands(different additional column- and lin-offsets)

• S. 13: Geolocation of VCS-HRV data with subsets of Fehmarn (differentadditional column- and lin-offsets)

• S. 14: Geolocation of VCS-HRV data with subsets of Portugal (differentadditional column- and lin-offsets)

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• S. 15: Geolocation of VCS-HRV data with subsets of Bergen (differentadditional column- and lin-offsets)

• S. 16: Geolocation of VCS-HRV data with subsets of Greek Islands (dif-ferent additional column- and lin-offsets)

• S. 17: Geolocation of VCS-HRV data with subsets of Western Irland (dif-ferent additional column- and lin-offsets)

• S. 18: Geolocation of VCS-HRV data with subsets of Teneriffa and GranCanaria

• S. 19: Geolocation of VCS-HRV data with subsets of Gomera, Hierro, andLa Palma

• S. 20: Geolocation of VCS-HRV data with subsets of Fuerte Ventura andLanzarote

• S. 21: Geolocation of VCS-HRV data of the subset of all Canary Islands

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Balearic Islands (June 2004) VCS-XPIF VIS008

Greek Islands (June 2004) VCS-XPIF VIS008

Bergen (June 2004) VCS-XPIF VIS008

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Western Ireland (June 2004) VCS-XPIF VIS008

Fehmarn (June 2004) VCS-XPIF VIS008

Portugal (June 2004) VCS-XPIF VIS008

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4+1

Balearic Islands (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028



12

Fehmarn (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028



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Portugal (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028

Portugal (June 2004)VCS-XPIF HRVL_offset = 5566C_offset = 2028

Portugal (June 2004)

VCS-XPIF HRV L_offset = 5572 C_offset = 2029

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Bergen (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028



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Greek Islands (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028

Greek Islands (June 2004)VCS-XPIF HRVL_offset = 5566C_offset = 2028

Greek Islands (June 2004) - Penteli, Thission -

VCS-XPIF HRV L_offset = 5572 C_offset = 2027

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Western Ireland (June 2004)VCS-XPIF HRVL_offset = 5568C_offset = 2028



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Teneriffa (June 2004)

VCS-XPIF HRV L_offset = 5570,5 C_offset = 2031

Gran Canaria (June 2004)


C7

C1

C5

C2

C6

C4C3

C0

T0

T1

TD

T3

T2

T3

T2

TD

T1

T0

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P1

H2

H1

G1G2

Gomera (June 2004)


Hierro (June 2004)


La Palma (June 2004)


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Fuerte Ventura (June 2004) VCS-XPIF HRVL_offset = 5570,5 C_offset = 2030

Lanzarote (June 2004)


F3

F1

F2

L2

L1

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The Canary Islands (June 2004), VCS-XPIF HRV L_offset = 5570,5; C_offset = 2031

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Heliosat3 WP4010 D13.1 Geolocation

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