Landscan: Difference between revisions
| (4 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
== About == | == About == | ||
The Landscan dataset is generally considered the best spatial population density dataset available. | The Landscan dataset is generally considered the best spatial population density dataset available. It has been updated yearly, although many of the inter-year changes are improvements to the overall model. Therefore, changes in population density from year to year will be due to a combination of real changes in data (births, deaths, migrations), and artificial changes, due to improved methods. | ||
== Getting Access == | == Getting Access == | ||
Data from 2011 is available from the http://www.imperial.ac.uk/admin-services/library/subject-support/earth-science-and-engineering/landscan/ Imperial Library]. Before that, we had to purchase individual licenses from EastView. | Data from 2011 is available from the [http://www.imperial.ac.uk/admin-services/library/subject-support/earth-science-and-engineering/landscan/ Imperial Library]. Before that, we had to purchase individual licenses from EastView. | ||
== File Format == | == File Format == | ||
The data comes as an HDR/FLT pair of files, for loading into ArcGIS. The HDR is a textfile of meta-data, and the FLT is an uncompressed binary grid. | |||
{| class="wikitable" | |||
!colspan="2"|Since ~2014 | |||
|- | |||
! style="text-align:right;" scope="col" | Pixel resolution | |||
| style="text-align:left;" | 43200 x 21600 | |||
|- | |||
! style="text-align:right;" scope="col"| Geographical resolution | |||
| style="text-align:left;" | 1/120º x 1/120º | |||
|- | |||
! style="text-align:right;" scope="col"| Longitude range of first pixel | |||
| style="text-align:left;" | 180.0ºW - 179.99167ºE | |||
|- | |||
! style="text-align:right;" scope="col"| Latitude range of first pixel | |||
| style="text-align:left;" | 89.99167ºN - 90.0ºN | |||
|- | |||
! style="text-align:right;" scope="col"| Data / units: | |||
| style="text-align:left;" | People in pixel | |||
|- | |||
! style="text-align:right;" scope="col"| No Data Value: | |||
| style="text-align:left;" | -9999 | |||
|} | |||
{| class="wikitable" | |||
!colspan="2"|Before ~2013 | |||
|- | |||
! style="text-align:right;" scope="col" | Pixel resolution | |||
| style="text-align:left;" | 43200 x 20880 | |||
|- | |||
! style="text-align:right;" scope="col"| Longitude range of first pixel | |||
| style="text-align:left;" | 180.0ºW - 179.99167ºE | |||
|- | |||
! style="text-align:right;" scope="col"| Latitude range of first pixel | |||
| style="text-align:left;" | 83.99167ºN - 84.0ºN | |||
|} | |||
* The FLT file is made of 32-bit (4-byte) floats - even though the numbers are integer. They are also LSB-first, which means in languages like Java, you have to flip the byte-order, but in C you don't. | |||
* Java: use Float.intBitsToFloat(Integer.reverseBytes(inputstream.readInt())); | |||
== Example Code == | == Example Code == | ||
Latest revision as of 17:46, 9 February 2017
About
The Landscan dataset is generally considered the best spatial population density dataset available. It has been updated yearly, although many of the inter-year changes are improvements to the overall model. Therefore, changes in population density from year to year will be due to a combination of real changes in data (births, deaths, migrations), and artificial changes, due to improved methods.
Getting Access
Data from 2011 is available from the Imperial Library. Before that, we had to purchase individual licenses from EastView.
File Format
The data comes as an HDR/FLT pair of files, for loading into ArcGIS. The HDR is a textfile of meta-data, and the FLT is an uncompressed binary grid.
| Since ~2014 | |
|---|---|
| Pixel resolution | 43200 x 21600 |
| Geographical resolution | 1/120º x 1/120º |
| Longitude range of first pixel | 180.0ºW - 179.99167ºE |
| Latitude range of first pixel | 89.99167ºN - 90.0ºN |
| Data / units: | People in pixel |
| No Data Value: | -9999 |
| Before ~2013 | |
|---|---|
| Pixel resolution | 43200 x 20880 |
| Longitude range of first pixel | 180.0ºW - 179.99167ºE |
| Latitude range of first pixel | 83.99167ºN - 84.0ºN |
- The FLT file is made of 32-bit (4-byte) floats - even though the numbers are integer. They are also LSB-first, which means in languages like Java, you have to flip the byte-order, but in C you don't.
- Java: use Float.intBitsToFloat(Integer.reverseBytes(inputstream.readInt()));
Example Code
Citation
This product was made utilizing the LandScan (insert dataset year)™ High Resolution global Population Data Set copyrighted by UT-Battelle, LLC, operator of Oak Ridge National Laboratory under Contract No. DE-AC05-00OR22725 with the United States Department of Energy. The United States Government has certain rights in this Data Set. Neither UT-BATTELLE, LLC NOR THE UNITED STATES DEPARTMENT OF ENERGY, NOR ANY OF THEIR EMPLOYEES, MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THE DATA SET.