HDF-EOS Vector Data


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Source: http://hdfeos.org/workshops/ws04/presentations/Suresh/Suresh.ppt

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HDF-EOS Vector Data

  1. 1. HDF-EOS Vector Data Eugene Chi, Liping Di, R.Suresh NASA/RITSS Email: suresh@rattler.gsfc.nasa.gov 1
  2. 2. INTRODUCTION HDF EOS library was primarily designed to support raster data from Terra and other follow on projects An increasing need to use Terra data with GIS applications for regional and local use Integration of Terra data with vector data will create new applications and usage Many GIS users will be able to access and use Terra data 2
  3. 3. HDF EOS Library HDF-EOS Swath HDF-EOS GRID HDF-EOS Point 3
  4. 4. Vector Data Requirements Need to support additional data types GIS Users require vector data support ESIP user community requested vector data support Many ESIP investigators use vector data with Terra data Advantages: Terra data will be available to a new community of GIS users Increase in Terra data use for many new applications Vector data support will increase data inter use Enhances data interoperability Support for OGC WMT implementation 4
  5. 5. A Vector Data Set 5
  6. 6. A Vector Structure Point Geometry and Attribute PX 1.0 10.0 15.0 3.0 PX 1.0 1.0 15.0 10.0 Building Number Building Name 1 Physics 2 Earth Science 3 Mathematics 4 Chemistry 6
  7. 7. A Vector Structure (cont) Line Geometry and Attribute Line ID PX PY 1 1.0 1.0 1 10.0 1.0 1 15.0 15.0 2 15.0 15.0 2 3.0 10.0 3 3.0 10.0 3 1.0 1.0 Street Name Campus Drive Stadium Drive Valley Road 7
  8. 8. A Vector Structure (cont) Polygon Geometry and Attribute Polygon ID Line ID 1 1 2 1 3 Contiguity 1 Line ID Left Poly Right Poly 1 1 -1 Section 2 1 -1 Main Campus 3 1 -1 8
  9. 9. Components of the Vector Interface Access Definition Basic I/O Inquiry Subset 9
  10. 10. The Vector Interface Routine Name Category Access C FORTRAN Description VCopen VCcreate Vcopen Vccreate VCattach VCdetach VCclose Vcattach Vcdetach Vcclose Definition VCdefpoint VCdefline VCdefpoly Vcdfpt Vcdfline Vcdfpoly Creates a new file or opens an existing one Creates a new vector data set and returns a handle Attaches to an existing vector data set Releases a vector data set and frees memory Closes the HDF-EOS file and deactivates the vector interface Define point attribute fields of a vector Define line attribute fields of a vector Define polygon attribute fields of a vector Basic I/O VCwritepoint VCreadpoint VCupdatepoint VCwriteline VCreadline VCupdateline VCwritepoly VCreadpoly Vcwrpt Vcrdpt Vcuppt Vcwrline Vcrdline Vcupline Vcwrpoly Vcrdpoly Writes (appends) new point records to a vector Reads point records from a vector Updates the specified point records of vector Writes (appends) new line records to vector Reads line records from a vector Updates the specified line records of vector Writes (appends) new polygon records to a vector Reads polygon records from a vector 10
  11. 11. The Vector Interface (cont) VCupdatepoly VCwriteattr Subset VCreadattr VCnpoints VCnlines VCnpolys vcrdattr vcnpts vcnlines vcnpolys VCpointinfo VClineinfo VCpolyinfo VCattrinfo VCinqattrs Inquiry vcuppoly vcwrattr vcptnfo vclninfo vcplinfo vcattrinfo vcinqattrs VCinqvector VCdefboxregion VCregioninfo VCregionrecs vcinqvc vcdefboxreg vcreginfo vcregrecs Vcextractregion vcextreg Updates the specified polygon records of a vector Creates or updates an attribute of the vector data set Reads existing attribute of vector data set Returns the number of points in a vector data set Returns the number of lines in a vector data set Returns number of polygons defined in a vector data set Returns information about a given point Returns information about a given line Returns information about a given polygon Returns information about a vector attribute Retrieves number and names of attributes defined for the vector data set Retrieves number and names of vectors in file Define region of interest by latitude and longitude Returns information about defined region Returns # of points, lines, polygons and records within the region Read a region of interests from a set of fields 11
  12. 12. Vector Subsetting Features By Geolocation – – – – VCdefboxregion VCregioninfo VCregionrecs VCextractregion 12
  13. 13. Tips on Writing a Vector Attribute fields – The name, type, order, and number of the attributes of point, line, and polygon are defined by users when first using them in a vector structure. – Once defined, the attributes are fixed with respect to the vector. 13
  14. 14. Compression Method for Vectors NONE 14