High Resolution Elevation (HRE)

Long name High Resolution Elevation
Short name HRE
File extension(s) .hr1, .hr2, .hr3, .hr4, .hr5, .hr6, .hr7, .hr8. .hrz
Data distributor

National Geospatial-Intelligence Agency (NGA)
National System for Geospatial Intelligence (NSG)

Sections

Data product name and description
Distribution disk files
Returned data
Returned file-level metadata
Returned metadata for individual rasters
Returned metadata for the XML Data Extension segment
References

Data product name and description

Name Description Level
HREGP HREGP data is cast on a geographic projection and primarily covers large geospatial areas (nominally region-sized). HREGP products are typically tiled to allow them to be joined into these large area configurations. The HREGP data set's horizontal and vertical values are horizontally and vertically coincident at the data set edges. That is, the adjacent HREGP product coincident points' horizontal coordinates and vertical elevation values will be the same. 1

HRE80
HRE40
HRE20
HRE10
HRE05
HRE02
HRE01

HRE80-HRE01 data is cast on the Universal Transverse Mercator (UTM) projection and primarily cover localized area data set extents. HRE80-HRE01 data sets are designed to be spatially contained within a single UTM zone. Adjacent data sets within one UTM zone are horizontally coincident at the data set edge, but adjacent data sets in adjacent UTM zones are not horizontally coincident at the data set edge. Vertical elevation values may (but are not required to) match across HRE80-HRE01 levels for the same geographic area or elevation point.

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Distribution disk files

File Name File Type Required Contents

.hr1
.hr2
.hr3
.hr4
.hr5
.hr6
.hr7
.hr8

NITF V2.1 Yes Each HRE NITF 2.1 file contains:
  • File header
  • Extended header data to include the PIAPRD Tagged Record Extension
  • Image subheader for DEM height data
  • DEM height data
  • Optional error propagation image segment header and data
  • XML Metadata Data Extension segment

File naming convention

The following naming convention will be used for the identification of the High Resolution Elevation (HRE) product files:

HRErrtDDMMSShDDDMMSSe_cxx.hrz

The file name convention is defined as follows:

Important notes to the user:

  1. GDB data support of HRE is read-only. Imported HRE data is not write-supported.
  2. HRE data sets are distributed in CD or DVD format. They have the required directory structure and file name. GDB uses this directory structure and file name to identify the product and obtain useful information. The directory structure and file name must be maintained when the CD or DVD is copied; otherwise an error will occur.
  3. To open an HRE data set, select the .hrz file. A window with the DTEM height data and other optional image data (for example, region data, scale factor data, and RE sigma data) will appear, along with a data size list. Select one of the data options to open it.
  4. To open DTEM data, use the original file name. To open other optional imagery data, input “:NITF:Raster:X” after the file name. X is the image index starting at 1. The following is an example of how to open indexed image data from an NITF file in EASI.
    EASI> fili = path/filename.ext:NITF:Raster:1
    

Returned data

Data Product Data Returned Details
DTEM post-height data One raster channel (data type is 32-bit real) GDB retrieves DTEM post-height data as a raster channel. The data is stored as 32-bit real numbers. GDB also retrieves the image subheader information as its associated metadata.
Region by post data(optional) One raster channel (data type is 8-bit integer) This image segment is comprised of the image subheader information and rigorous error propagation post-by-post region definition data. This is an optional image segment, as the regions may also be defined by specifying polygon boundaries in the XML Data Content Data Extension Segment (DES).
Random error scale factors by post data (optional) One raster (data type is 32-bit real) This image segment is comprised of the image subheader information and random error scale factors by post data. These scale factors are used in conjunction with region-by-region nominal random error covariance matrices defined in the XML Data Content Data Extension Segment (DES).
Random error covar by post data (optional) Three raster channels This image segment is comprised of the image subheader information and the random error covariance by post data. The random error covariance data is input as standard deviation terms that when squared, make up the diagonal terms of the random error covariance matrices.
Random correlation coefs by post data (optional) Three raster channels This image segment is comprised of the image subheader information and random error correlation coefficients by post data. The random error correlation coefficient data (when multiplied by the corresponding diagonal term standard deviations) makes up the off-diagonal terms of the random error covariance matrices.
General information and metadata Text segment Metadata associated with the DTEM data is contained in the XML Data Content Data Extension Segment (XML_DATA_CONTENT DES). A single XML_DATA_CONTENT DES is included in every NITF-formatted HRE data file. This data extension segment is comprised of subheader information and XML-formatted metadata.

Returned file-level metadata

File-level metadata includes three parts: NITF file header metadata, XML Data Content Segment metadata, and extended header data (Profile for Imagery Access Product Support Extension data).

The following are the main file-level metadata tags that are returned:

Name Description Values
FH.FHDR File profile name NITF02.10
FH.FTITLE The title of the file

HRE High Resolution Elevation Data
HRErrtDDMMSShDDDMMSSe_cxx.hrf

FH.ONAME

Originator’s name
A valid name for the operator or organization who created the file

US National Geospatial-Intelligence Agency
FH. FSCLSY

File security classification system
Valid values indicating the national or multinational security system used to classify the file

Use country codes as defined in FIPS PUB 10-4 to indicate national security systems.
FH. STYPE Standard type or capability BF01 (indicates that this file is formatted using ISO/IEC IS 12087-5)
FH. OSTAID Originating station ID Identification code or name of the originating organization, system, station, or product
FH. FSCTLH File control and handling Valid additional security control and/or handling instructions (caveats) associated with the file
fileIdentifier Unique identifier for this metadata file File name of the NITF file (or separate metadata file) that contains the metadata

language/
LanguageCode

Language used for documenting metadata Character string

characterSet/
MD_CharacterSetCode

Full name of the character coding standard used for the metadata set UTF-8

contact/
CI_ResponsibleParty/
organisationName

Name of the responsible organization Character string
dateStamp Date that the metadata was created YYYY-MM-DD
metadataStandardName Name of the metadata standard (including profile name) used ISO 19115 Geographic Information – Metadata
dataSetURI Uniform Resource Identifier (URI) of the data set to which the metadata applies Character string of the form "urn:nga-hre: filename"

referenceSystemInfo/
MD_ReferenceSystem/
referenceSystemIdentifier/
RS_Identifier/code

Alphanumeric value identifying one of the horizontal reference systems specified in this implementation profile WGS84E

identificationInfo/
MD_DataIdentification/
citation/CI_Citation
/title

Name by which the cited resource is known File name of the NITF file that contains the elevation data. See the above explanation of file naming conventions. Use the HRE naming scheme here.

contentInfo/
MD_CoverageDescription/
attributeDescription

Description of the attribute described by the measurement value A paired value (name, data type). For example: digitalSurfaceModel, Real
PIAPRD.ASSRPTREP ASSPRT repetitions “00”, indicating zero repeating SECTITLE values
PIAPRD.ATEXTnn

Associated Textnn
Provides the nnth text block further describing the imagery product. The number of ATEXTs between the previous field and this field is represented in the ATEXTREP field.

HRELLyyyymmdd

where:

  • HRE: required portion of keyword for HRE DTEM segment
  • LL: the two-character HRE product designator (for example, for HREGP, LL will be “GP”).
  • yyyymmdd: year, month, day

The format for any rigorous error image segments included will follow the same format pattern, with the first three letters changed to one of the following identification tags:

  • REG: required portion of keyword for rigorous error regions segment
  • RSF: required portion of keyword for rigorous error random error scale factor segment
  • COV: required portion of keyword for rigorous error propagation random error covariance segment
  • COR: required portion of keyword for rigorous error propagation random error correlation coefficient segment
PIAPRD.PRODCRTIME Producer time The date or the date and time that the product was created or last modified, expressed in ZULU time
PIAPRD.PRODSNME Product short name The abbreviated name of a product stored in the archive

Returned metadata for individual rasters

The following are the main metadata tags for individual rasters that are returned:

Name Description Values
ISH.IM File part type Field containing the characters “IM” to identify the subheader as an image subheader
ISH.ABPP Actual bits-per-pixel per band Field containing the number of significant bits for the value in each band of each pixel without compression
ISH.ICAT

Image category
Field containing a valid indicator of the specific category of image, raster, or grid data

MATR (indicates Matrix Data)
ISH.NBANDS Number of bands Field containing the number of data bands within the specified image
ISH.NCOLS Number of significant columns in image Field containing the total number of columns of significant pixels in the image
ISH.NROWS Number of significant rows in image Field containing the total number of rows of significant pixels in the image
ISH.ISORCE Image source Field containing a description of the source of the image
ISH.IREP

Image representation
Field containing  a valid indicator of the processing required in order to display an image

NODISPLY (indicates data not intended for display)
ISH.IC

Image compression
Field containing a valid code indicating the form of compression used in representing the image data

Valid codes:
  • NC: not compressed
  • NM: uses a pixel mask table

Returned metadata for the XML Data Extension segment

Name Description Values
DE File part type Field containing the characters "DE" to identify the subheader as a data extension
DESID Unique DES type identifier Field containing the following string: XML_DATA_CONTENT
DESSHF XML file type Field containing data that is representative of the XML file type
DESSHL DES user-defined subheader length Field containing the number of bytes in the DESSHF field
DESDATA User-defined data field Field containing the XML data. The length of this field will not cause any other NITF field length limits to be exceeded, but is otherwise fully user-defined.

References

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