HGT - Revision history

DavidBoddie: /* Software */

2014-04-27T01:05:24Z

‎Software

DavidBoddie at 00:57, 27 April 2014

2014-04-27T00:57:15Z

DavidBoddie: /* Sample files */

2014-04-27T00:38:28Z

‎Sample files

Dan Tobias: Probably Geospatial should be the primary category.

2014-04-26T18:54:47Z

Probably Geospatial should be the primary category.

DavidBoddie: /* Links */

2014-04-26T17:08:14Z

‎Links

DavidBoddie: /* Format */

2014-04-26T16:48:29Z

‎Format

DavidBoddie: Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics |extensions={{ext|hgt}} }} Height files contain elevation data for regions of the Earth's surface described by the name o..."

2014-04-26T16:31:37Z

Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics |extensions={{ext|hgt}} }} Height files contain elevation data for regions of the Earth's surface described by the name o..."

New page

{{FormatInfo
|formattype=electronic
|subcat=Graphics
|extensions={{ext|hgt}}
}}

Height files contain elevation data for regions of the Earth's surface described by the name of the file. Each file describes a tile with a height of one degree of latitude and a width of one degree of longitude. The name of each file refers to the latitude and longitude at the lower left corner of the tile.

== Format ==
Each file consists of a sequence of 16-bit signed values stored in big-endian [[Endianness|byte order]], arranged in row major order, meaning that the samples for each row are stored consecutively. The total number of values depends on the dimensions of the dataset held by each file. For 1 arc-second resolution data, each file will contain 3601 * 3601 values; for 3 arc-second resolution data, each file will contain 1201 * 1201 values.

The order of rows runs from north to south and the order of values in each row runs from west to east. This means that the first value in the last row in each file corresponds to the position specified by the name of the file. Each tile described by the data overlaps adjacent tiles to the north and south by a single row in each direction, and to the west and east by a single column in each direction. In other words, the first row of values in a file is the same as the last row of values in the file that describes the tile immediately to the north of it. Similarly, the last column of values will be the same as the first column of values in the file that describes the tile immediately to the east of it.

== Identifiers ==
The filename extension '''.hgt''' is used.

== Software ==

== Sample files ==
* [http://dds.cr.usgs.gov/srtm/version2_1/ SRTM Version 2.1 datasets]

== Links ==
* [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/ SRTM Topography]

← Older revision		Revision as of 01:05, 27 April 2014
Line 17:		Line 17:

	== Software ==		== Software ==
		+	* [https://bitbucket.org/dboddie/python-hgt python-hgt] - Python module and tools for reading height (hgt) files.

	== Sample files ==		== Sample files ==

@@ Line 4: / Line 4: @@
 |extensions={{ext|hgt}}
 }}
-'''HGT''' (Height) files contain elevation data for regions of the Earth's surface described by the name of the file. Each file describes a tile with a height of one degree of latitude and a width of one degree of longitude. The name of each file refers to the latitude and longitude at the lower left corner of the tile.
+'''HGT''' (Height) files contain elevation data for regions of the Earth's surface, as acquired by the Shuttle Radar Topography Mission (STRM). The location of the region for data contained in a file is described by the name of the file itself. Each file describes a tile with a height of one degree of latitude and a width of one degree of longitude. The name of each file refers to the latitude and longitude at the lower left corner of the tile.
 == Format ==
@@ Line 23: / Line 23: @@
 == Links ==
 * [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/ SRTM Topography]
 * [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/Continent_def.gif Continent definitions] showing the regions covered by the data.
 [[Category:Graphics]]

← Older revision		Revision as of 17:08, 26 April 2014
Line 24:		Line 24:
	== Links ==		== Links ==
	* [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/ SRTM Topography]		* [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/ SRTM Topography]
		+	* [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/Continent_def.gif Continent definitions] showing the regions covered by the data.

@@ Line 20: / Line 20: @@
 == Sample files ==
 * [http://dds.cr.usgs.gov/srtm/version2_1/ SRTM Version 2.1 datasets]
 == Links ==

@@ Line 1: / Line 1: @@
 {{FormatInfo
 |formattype=electronic
-|subcat=Graphics
+|subcat=Geospatial
 |extensions={{ext|hgt}}
 }}
+'''HGT''' (Height) files contain elevation data for regions of the Earth's surface described by the name of the file. Each file describes a tile with a height of one degree of latitude and a width of one degree of longitude. The name of each file refers to the latitude and longitude at the lower left corner of the tile.
 Height files contain elevation data for regions of the Earth's surface described by the name of the file. Each file describes a tile with a height of one degree of latitude and a width of one degree of longitude. The name of each file refers to the latitude and longitude at the lower left corner of the tile.
 == Format ==
@@ Line 25: / Line 24: @@
 * [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/ SRTM Topography]
 * [http://dds.cr.usgs.gov/srtm/version2_1/Documentation/Continent_def.gif Continent definitions] showing the regions covered by the data.

@@ Line 9: / Line 9: @@
 == Format ==
 Each file consists of a sequence of 16-bit signed values stored in big-endian [[Endianness|byte order]], arranged in row major order, meaning that the samples for each row are stored consecutively. The total number of values depends on the dimensions of the dataset held by each file. For 1 arc-second resolution data, each file will contain 3601 * 3601 values; for 3 arc-second resolution data, each file will contain 1201 * 1201 values.
 The order of rows runs from north to south and the order of values in each row runs from west to east. This means that the first value in the last row in each file corresponds to the position specified by the name of the file. Each tile described by the data overlaps adjacent tiles to the north and south by a single row in each direction, and to the west and east by a single column in each direction. In other words, the first row of values in a file is the same as the last row of values in the file that describes the tile immediately to the north of it. Similarly, the last column of values will be the same as the first column of values in the file that describes the tile immediately to the east of it.