Header

UZH-Logo

Maintenance Infos

An automatic method to create flow lines for determination of glacier length: A pilot study with Alaskan glaciers


Le Bris, Raymond; Paul, Frank (2013). An automatic method to create flow lines for determination of glacier length: A pilot study with Alaskan glaciers. Computers & Geosciences, 52(3):234-245.

Abstract

Glacier length is a key parameter in global glacier inventories, but difficult to determine in a consistent way and subject to frequent change. Its vector representation (a flow line) is a most important input for modeling future glacier evolution, but only seldom available from digital databases. Hence, there is an urgent need to generate such flow lines for a large number of glaciers from automated methods. We here present a new algorithm that is based on Python scripting and additional libraries (GDAL and OGR) and requires only a DEM and glacier outlines as an input. The core of the method is based on a glacier axis concept that is combined with geometry rules such as the k-d Tree, Nearest Neighbor and crossing test theory. We have applied the method to 400 glaciers located in Western Alaska, where a new glacier inventory was recently created. The accuracy of the method was assessed by a quantitative and qualitative (outline overlay) comparison with a manually digitized dataset for 20 glaciers. This comparison revealed for 17 out of the 20 glaciers a length value within the range of the manual digitizations. Other potential methods performed less well. Combined with previous glacier outlines from the same region (Digital Line Graph) we automatically determined length changes for 390 glaciers over a c. 50 year period.

Abstract

Glacier length is a key parameter in global glacier inventories, but difficult to determine in a consistent way and subject to frequent change. Its vector representation (a flow line) is a most important input for modeling future glacier evolution, but only seldom available from digital databases. Hence, there is an urgent need to generate such flow lines for a large number of glaciers from automated methods. We here present a new algorithm that is based on Python scripting and additional libraries (GDAL and OGR) and requires only a DEM and glacier outlines as an input. The core of the method is based on a glacier axis concept that is combined with geometry rules such as the k-d Tree, Nearest Neighbor and crossing test theory. We have applied the method to 400 glaciers located in Western Alaska, where a new glacier inventory was recently created. The accuracy of the method was assessed by a quantitative and qualitative (outline overlay) comparison with a manually digitized dataset for 20 glaciers. This comparison revealed for 17 out of the 20 glaciers a length value within the range of the manual digitizations. Other potential methods performed less well. Combined with previous glacier outlines from the same region (Digital Line Graph) we automatically determined length changes for 390 glaciers over a c. 50 year period.

Statistics

Citations

13 citations in Web of Science®
14 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

104 downloads since deposited on 03 Nov 2013
34 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2013
Deposited On:03 Nov 2013 13:34
Last Modified:05 Apr 2016 17:05
Publisher:Elsevier
ISSN:0098-3004
Publisher DOI:https://doi.org/10.1016/j.cageo.2012.10.014

Download

Preview Icon on Download
Content: Published Version
Language: English
Filetype: PDF - Registered users only
Size: 2MB
View at publisher
Preview Icon on Download
Preview
Content: Accepted Version
Language: English
Filetype: PDF
Size: 2MB