1 / 22

dVoy Grid Description Format Considerations

dVoy Grid Description Format Considerations. ESRI ASCII Raster. ARC ASCIIGRID refers to a specific interchange format developed for ARC/INFO rasters. The format consists of a header that specifies the geographic domain and resolution, followed by the actual grid cell values. It looks like this:

enya
Download Presentation

dVoy Grid Description Format Considerations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. dVoy Grid Description Format Considerations

  2. ESRI ASCII Raster ARC ASCIIGRID refers to a specific interchange format developed for ARC/INFO rasters. The format consists of a header that specifies the geographic domain and resolution, followed by the actual grid cell values. It looks like this: ncols 157nrows 171xllcorner -156.08749650000yllcorner 18.870890200000cellsize 0.008333000 0 1 1 1 2 3 3 5 6 8 9 12 14 18 21 25 30 35 41 47 5359 66 73 79 86 92 97 102 106 109 112 113 113 113 111 109 106103 98 94 89 83 78 72 67 61 56 51 46 41 37 32 29 25 22 19etc... Note: Only allows square grid cells

  3. GeoTiFF Provides information for georeferencing TiFF images. Geotiff_Information: Version: 1 Key_Revision: 0.1 Tagged_Information: ModelTiepointTag (2,3): 0 0 0 576496.823 4660453.59 0 ModelPixelScaleTag (1,3): 25.400001 25.400001 0 End_Of_Tags. Keyed_Information: GTModelTypeGeoKey (Short,1): ModelTypeProjected GTRasterTypeGeoKey (Short,1): RasterPixelIsArea ProjectedCSTypeGeoKey (Short,1): PCS_WGS84_UTM_zone_17N PCSCitationGeoKey (Ascii,25): "UTM Zone 17 N with WGS84" End_Of_Keys. End_Of_Geotiff.PCS = 32617 (WGS 84 / UTM zone 17N)Projection = 16017 (UTM zone 17N)Projection Method: CT_TransverseMercator ProjNatOriginLatGeoKey: 0.000000 ( 0d 0' 0.00"N) ProjNatOriginLongGeoKey: -81.000000 ( 81d 0' 0.00"W) ProjScaleAtNatOriginGeoKey: 0.999600 ProjFalseEastingGeoKey: 500000.000000 ProjFalseNorthingGeoKey: 0.000000GCS: 4326/WGS 84Datum: 6326/World Geodetic System 1984Ellipsoid: 7030/WGS 84 (6378137.00,6356752.31)Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)Projection Linear Units: 9001/meter (1.000000m)Corner Coordinates:Upper Left ( 576496.823,4660453.588) ( 80d 4'29.95"W, 42d 5'32.78"N)Lower Left ( 576496.823,4518391.383) ( 80d 5'34.76"W, 40d48'46.70"N)Upper Right ( 759427.631,4660453.588) ( 77d51'54.10"W, 42d 3'11.98"N)Lower Right ( 759427.631,4518391.383) ( 77d55'33.34"W, 40d46'32.06"N) Adds TiFF compliant tags for projection and coordinate system http://remotesensing.org/geotiff/geotiff.html

  4. GeoTiFF .NET http://www.positionintegrity.com/geotiff.jsp

  5. OGC Coverage Specification Provides interfaces for getting values from data sets based on location • OGC Grid Coverages are based on GeoTiff but support other formats such as HDF-EOS • Includes interfaces for • Grid Analysis (histograms and coverage statistics) • Grid Processing (filtering, smoothing, etc.) http://www.opengis.org/techno/specs/01-004.pdf

  6. GML Coverages OGC’s Geography Markup Language supports Grid Coverages in ASCII and Binary formats Example for a 3X3 grid with values of temperature and pressure temp, pres Uses ‘envelope’ for bounding rectangle http://www.opengis.org/techno/documents/02-023r4.pdf

  7. GML Coverages Example #2 <map:PointArray gml:srsName="#local" ... > <map:origin> <map:PointArray> <map:origin> <gml:Point> <gml:coord> <gml:X>600</gml:X> <gml:Y>800</gml:Y> </gml:coord> </gml:Point> </map:origin> <map:offset osf:count="15"> <osf:Vector osf:uom="units.xml#m"> <osf:component osf:axis="1"> <osf:Quant>12</osf:Quant> </osf:component> <osf:component osf:axis="2"> <osf:Quant>0.0</osf:Quant> </osf:component> </osf:Vector> </map:offset> </map:PointArray> </map:origin> <map:offset osf:count="25"> <osf:Vector osf:uom="units.xml#m"> <osf:component osf:axis="1"> <osf:Quant>0.0</osf:Quant> </osf:component> <osf:component osf:axis="2"> <osf:Quant>8</osf:Quant> </osf:component> </osf:Vector> </map:offset> </map:PointArray> A 15*25 grid of points spaced 12m along the x-axis and 8m along y, with the origin at (600,800) could be encoded: http://www.ned.dem.csiro.au/XMML/issues/coverage.html

  8. HDF-EOS Based on HDF 5 Contains Grid/Point/Swath/ZA Interfaces Metadata includes: Dimensions Projection http://hdfeos.gsfc.nasa.gov/hdfeos/index.cfm HDF 5 XML project: I couldn’t find anything newer than 2 years old (they have a HDF DTD Schema) http://hdf.ncsa.uiuc.edu/HDF5/

  9. Earth Science Markup Language (ESML) • Led by the Information Technology and Systems Centerat University of Alabama in Huntsville and NASA • Specialized markup language for Earth Science information based on XML • Extends traditional metadata to include both structural and semantic information needed to effect a practical runtime interpretation of a data set • Existing products: • ESML Schema • ESML C++ Library • ESML Java Library • ESML Editor • ESML Data Browser http://esml.itsc.uah.edu/index2.html

  10. ESML Content Metadata • Content metadata are mainly used for human knowledge and web-searching • Content metadata in ESML are derived from FGDC and ECS metadata sets • Tools are planned for converting existing ECS metadata into ESML

  11. Syntactic Metadata - ASCII Data • ESML supports descriptions of the structures of data files in two basic data formats, Binary and ASCII

  12. Syntactic Metadata - Binary Data • ESML supports descriptions of the structures of data files in two basic data formats, Binary and ASCII

  13. Syntactic Metadata - HDF-EOS • Self-Describing Formats: • Descriptions of the structures of self-describing data files through their internal metadata • HDF, HDF-EOS, CDF, netCDF, etc • Additional data formats can be added as necessary

  14. Writing an ESML File (1) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> <Field name="SizeX" format="%d"> <Attribute/> </Field> <Field name="SizeY" format="%d"> <Attribute/> </Field> <Array occurs="5"> <Array occurs="5"> <Field name="BrightnessTemp" format="%f"> <Data unit="Degrees Kelvin"/> </Field> </Array> </Array> </AsciiStructure> </Ascii> </SyntacticMetaData> </a:ESML> ESML MARKUP FOR THE DATA FILE 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  15. Writing an ESML File (2) <a:ESML> <SyntacticMetaData> ONLY THE STRUCTURE 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  16. Writing an ESML File (3) <a:ESML> <SyntacticMetaData> <Ascii> DESCRIBE THE FORMAT 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  17. Writing an ESML File (4) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> ENTIRE FILE CONTENTS INTO 1 LOGICAL STRUCTURE 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  18. Writing an ESML File (5) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> <Field name="SizeX" format="%d"> <Attribute/> </Field> DEFINE THE FIRST FIELD IN THE FILE: HEADER INFORMATION 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  19. Writing an ESML File (6) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> <Field name="SizeX" format="%d"> <Attribute/> </Field> <Field name="SizeY" format="%d"> <Attribute/> </Field> DEFINE THE SECOND FIELD IN THE FILE: HEADER INFORMATION 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  20. Writing an ESML File (7) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> <Field name="SizeX" format="%d"> <Attribute/> </Field> <Field name="SizeY" format="%d"> <Attribute/> </Field> <Array occurs="5"> <Array occurs="5"> <Field name="BrightnessTemp" format="%d"> <Data unit="Degrees Kelvin"/> </Field> </Array> </Array> DEFINE THE DATA FIELD IN THE FILE: PROVIDE SIZE AND FORMAT INFORMATION 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  21. Writing an ESML File (8) <a:ESML> <SyntacticMetaData> <Ascii> <AsciiStructure geoInfo="NoGeoInfo" instances="1"> <Field name="SizeX" format="%d"> <Attribute/> </Field> <Field name="SizeY" format="%d"> <Attribute/> </Field> <Array occurs="5"> <Array occurs="5"> <Field name="BrightnessTemp" format="%d"> <Data unit="Degrees Kelvin"/> </Field> </Array> </Array> </AsciiStructure> </Ascii> </SyntacticMetaData> </a:ESML> CLOSE ALL THE TAGS: ESML FILE IS READY 5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SIMPLE ASCII DATA FILE

  22. dVoy Grid Data Type ? Extend the CAPITA HDF layer structure? Dimensions x, y, bounding rectangle Projection Projection Type and parameters Coordinate System (Datum)

More Related