Residual Relief Separation: DEM Enhancement for Geomorphological Mapping

Monday, 31 December, 2007

Hillier, J. and Smith, M.J.
Earth Surface Processes and Landforms, 33, 2266-2276.

Geomorphologically mapped data form a primary set of observations that can be used to infer former environmental conditions. Thus, objective and consistent mapping of landforms from remotely sensed data (e.g. satellite imagery, digital elevation models (DEMs) is paramount for reconstructing palaeo-environments.

This paper proposes a technique, “residual relief separation”, to enhance landforms in DEMs prior to visualization and digital mapping. This is applied to a ~600 km2 region surrounding Lough Gara, Ireland, where drumlins (~200 m wide) overlie a regional relief of hills (~10 km wide). Here, residual relief separation uses a difference in width-scale. Regional relief is approximated by a 1 km wide median filter, then subtracted to leave the drumlins in a “residual” topography. In a second step, the residual relief is normalized to allow for amplitude variations in the drumlins across the area (~5-40 m high). Finally, visualization uses a simple black-to-white colour scale for height.

Whilst not numerically out-performing other visualization techniques, this method performs equally well, and as the data are not “illuminated” there is no azimuthal bias. Additional benefits include the relatively simple calculation, intuitive visual comprehension, no emphasis of noise, and the possibility of using any desired visualization technique after the landscape has been topographically manipulated.

Introduction to the Journal of Maps Student Edition

Monday, 31 December, 2007

Smith, M.J. and Lynch, K.
Journal of Maps Student Edition, v2007, 1-10

This editorial introduces material for the launch edition of the Journal of Maps Student Edition. The Journal of Maps seeks to create greater exposure, and provide publishing opportunities, for researchers that have produced map content that would otherwise remain unpublished. To this end the journal is open access and, due to the all-encompassing inter-disciplinary nature of “maps”, publishes on a wide-range of topics. The Student Edition is targeted at supporting students in furthering their research careers. The quantity and quality of journal citations is one of the primary measures of academic success, yet few research programmes actively teach their students about academic publishing. With maps often one of the first outputs of research, the Student Edition can leverage its’ unique position across disciplines to offer a “first publishing opportunity”, thereby providing students with an environment through which they can learn from their experiences. All peer-reviews are completed internally with a focus upon positive outcomes and actionable points that can significantly improve the quality of the submission. The material presented in this issue all resulted from the British Geomorphological Research Group’s Postgraduate Spring Symposium in March 2006 hosted at the University of Ulster.

Editorial: summary of activities 2004-2007

Monday, 31 December, 2007

Smith, M.J.
Journal of Maps, v2007, 368-376

It has been an exciting period of growth at the Journal of Maps (JoM) overthe last three years and, as we come to the end of 2007, it seems particularlyappropriate to provide a summary of our activities, an outline of our futureplans and acknowledge the support from those involved with the journal.

GDAL/OGR 1.5 Released

Friday, 28 December, 2007

THe latest version of GDAL/OGR has now been released and is available for download. This is a fairly big upgrade with 29 new and updated raster drivers and 11 new and updated vector drivers. This includes support for BigTIFF, TerraSAR-X, Generic Bbinary, ISIS3, WMS, WFS, GPX, GMT and KML. So well worth a look at. You can also see who uses GDAL in their software. Much to my surpise, ESRI’s ArcGIS 9.2 was listed and you can see that they are using GDAL to extend the capabilities of import/export alongside their standard RDO drivers. Have a look at this tech support article.

Deeply functional!

Tuesday, 18 December, 2007

I was at the at the GRSG’s Annual Conference at the Geological Society in London today. This is one of my favourite conferences as it is low key, has commercial and academic members and brings together a wide variety of inter-disciplinary subjects. As ever, it was sponsored by the usual array of vendors, including InfoTerra. They were rather proudly showing a variety of Leica Geosystems Imagine brochures as from 2008 they will be the UK vendors. I’ve scanned the front page of the Leica Photogrammetry Suite (right) brochure which really did amuse me. Can anyone explain what “deep functionality” is?? And why is there a jet in the background with all its engines on fire, presumably plunging to Earth? Is it because the rather smug looking PC operator has just jammed all its navigation systems? Or perhaps he knows that the onboard maps were georeferenced with Imagine? Who knows… If anyone from Leica at Peachtree Corners (great address!) can enlighten me I’d be grateful.

Initial TopSat Data

Friday, 14 December, 2007

TopSatAs part of the availability of TopSat tasking to UK higher education, we had our initial request for three sites in Armenia approved and have just taken delivery of the first of these. Whilst the conditions were not ideal due to the presence of a large amount of snow at higher elevations, the 2.9m panchromatic and 5.7m RGB should be ideal for our use; namely acquiring ground control for classifying DMC data of Armenia. So other issues aside, when you zoom in on the data, as the screenshot shows, there are horrible block artefacts in the imagery. Whilst we have asked why this is, my guess is that this is lossy image compression, possibly applied at the satellite prior to download. At present it remains unfit for purpose (because I can’t actually see any trees even at 2.9m resolution!). Watch this space.

ArcMap Geometry

Thursday, 13 December, 2007

One of the “exciting new features” in ArcMap 9.2 is vector geomtry. What hifalutin new feature is this I hear you cry? What spatial treats has ESRI unleashed upon us? Well, have a look at the graphic (right) to see a new menu item (Calculate Geometry) that is available in the attribute table. If you select that you will be presented (dependent upon whether you have a point, line or poly layer) with the following dialogue box (below). And, excitement upon excitement, those of us not blessed with extensive VBA skills can now find out the location of our feature (or its length or perimeter and area).

OK, so I had a rant about this a little while ago and it’s nice to see it in the final product….

Peyton and Byrne @ St “Meet me at” Pancras

Tuesday, 11 December, 2007

I met a colleague at St Pancras recently and we decided to grab a quick coffee so headed to the nearest coffee bar which happened to be Peyton and Byrne, “a British Bakery”. All I can say is that if this is the state of British bakeries, please o please bring on the French. A luke warm cup of coffee, followed by a rock hard sandwich for my colleague was enough. And to cap it all off, someone walked off with my cuppa leaving a half-finished hot chocolate. Cheers!

Open Peer Review

Friday, 7 December, 2007

At the Journal of Maps we operate an open peer-review system when reviewing papers that have been submitted. Peer-review has been around for over 300 years and, as far as the academic commumnity is concerned, is the best method to review the quality of material for publication. That is not to say it is ideal because it is far from it, but a viable alternative remains to be found. Of course peer-review is simply a “quality check” on an individual’s work by their peers and with such a simple definition there is scope for a myriad of operational systems. In practice the primary concern comes down to whether the authors and/or reviewers remain anonymous. These are term single-blind and double-blind systems and the reasoning is that anonymity increases the likelihood of an unbiased review. This of course is a mute point and there have been a number of studies that looked at how these systems can be abused. This occurs in the form of “gift authorship” (where authorship is given to a minor party), redundant publication (multiple publication of principally the same work), but also covers plagiarism and deliberate delay (by referees). Whilst it is usually hard to retain author anonymity because of relatively small research communities, it is much easier to remain anonymous as a reviewer. This promotes the “pot shot” culture where a manuscript is an easy target for critcism. This is not good and most authors are familiar with the crushing feeling that an abusive review manifests. JoM therefore operates an open peer-review system where neither author or reviewer remains anonymous. We believe that reviewers are responsible for their comments and should be able to stand by them. Whilst the general principle is sound, this is open to subtle abuse. For example, a reviewer of a manuscript from a “well known” author might be reluctant to be overtly critical regardless of the quality of the manuscript. I know of colleagues who, whilst being the most appropriate reviewers, have refused on the grounds that it might not be the best career choice!It is notable that there are general “norms” for peer-review across disciplines, with spatial subjects (geography, geology) being quite conservative. Single and double blind systems are common and there is a certain amount of the “pot shot” culture (although any good editor will mitigate against this). Other subjects are much more liberal in their reviewing methods. This can include the public posting of a manuscript for comment and revision by any interested parties, prior to publication. This opens up the opportunity for significant contribution by other researchers and, in certain circumstances, it is appropriate for co-authorship to be offered. Indeed, peer-review offers the opportunity for significant “value added” through the improvement of a manuscript. I believe at JoM that nearly all maps have seen improvement as a result of review, with a small proportion significantly improved. It would be nice to think that in these instances joint-authorship might be a consideration.

Standard Normal Transform

Tuesday, 4 December, 2007

Following on from the previous post on animating a stem and leaf plot for teaching, here is another one on a standard normal transforms.