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Auto Generated Orienteering Maps for WOC 2016

Topo socks

Really? Auto generated orienteering maps?

Well yes and no. Read all about it on the WOC Sweden 2016 website. If you haven’t seen such maps before you will be surprised if not amazed. Continue reading Auto Generated Orienteering Maps for WOC 2016

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ELVIS rocks with LiDAR contours

image Elvis storm 1998

ELVIS delivers 1m, 5m, 25m contours – free!

ELVIS is Geoscience Australia’s new elevation information system. It is free, licenced under Creative Commons and makes public LiDAR data very accessible. Thank you to Russell Rigby, mapping convenor ONSW who made me aware of ELVIS. The LiDAR data available is;

  • SRTM-derived 1 Second Digital Elevation Models Version 1.0
  • DEM SRTM 1 Second Hydrologically Enforced
  • 5 metre Digital Elevation Model (DEM) – this delivers 1m, 5m, 25m contours

I downloaded 5m DEM data covering part of the 2015 Anglesea mtbo map, imported contours into OCAD and overlaid those on the OCAD map file of 5m contours. The correspondence was very close which is a tribute to mapper John Sutcliffe as much as to the ELVIS data.

The Coverage

The 5m resolution coverage, which provides down to 1m contours, is fairly thin. These surveys cover Australia’s populated coastal zone; floodplain surveys within the Murray Darling Basin, and some parts of  major and minor population centres.

Maybe we will see more sand dune coastal area maps akin to those near Hobart,  Auckland, Levin and Invercargill. And perhaps street and park-O where more detailed contours are desired.

Ease of use

The website isn’t yet the friendliest until you get to know it and then it does work well. Here are tips based on my learning;

Symbols of available datasets1m Hydrologically enforced DEM

  • Selecting  a right arrowhead symbol provides a synopsis of that data type.
  • Selecting a download arrow symbol takes you to the selection of data coverage for your project.
  • Selecting the globe symbol, (red when selected) shows on the map at left, the available coverage for that data.
  • Selecting the ‘eye’ symbol (orange when selected) show the extent of  that data coverage.
  • Note the latter two symbols act like check boxes, not radio buttons.
map of ELVIS 5m data coverage, eastern states
ELVIS 5m data coverage, eastern states

 Selecting a 5m dataset5m DEM for Victoria

  • At time of writing, selecting the name of any state 5m dataset gives you identical national information. It also has links at right (when selected) to state mosaic downloads – these are of no relevance to OCAD use.
  • Selecting the download icon frames the 5 metre DEM coverage area for that state.

Download of data

Whichever dataset you choose, the method of selecting data is the same. The download wizard is easy to follow.

  • For Output Format, select Esri ASCII Grid for OCAD import. The file will be a .asc type file.
  • For Coordinate system, select GDA94 for OCAD import.

OCAD import

The easiest method is to use the DEM import wizard available in OCAD 12 (OCAD 10 & 11 users, see the video tutorials link below); http://ocad.com/wiki/ocad12/en/index.php?title=DEM_Import_Wizard. The defaults provided in the wizard are adequate for a first run.

You can select 1m, 5m and 25m Contour Lines and produce background maps of any or all of Slope Gradient, Hill Shading, Hypsometric Map.

Tutorials

There are 4 video tutorials on DEM at http://ocad.com/en/support/learn-video. These videos are useful for OCAD 10, 11 and 12 users.

I created a 4 minute video tutorial on the basics of using ELVIS. View it online at www.screencast.com/t/y3MTbMzzO

And here is a base OCAD file I created to import the DEM data and then in turn it is imported into your OCAD map file with minimal symbology and colours.

ELVIS issues

ELVIS striation issue Wilsons Prom
ELVIS striation Wilsons Prom

Russell Rigby detected an issue that is mainly evident in steeper areas. The contours have a degree of blockiness or striations. Russell has made Geoscience Australia aware of this issue.

This is strongly evident in the steep Wilson’s Promontory contours at right.

It is less evident but still distinguishable as a series of  ‘steps’ in the less steep Preston contours below right.

In many orienteering areas, the issue won’t be much of a problem. For example in the Anglesea contours, I had to inspect closely to detect the striations.

 

ELVIS improvements

ELVIS striation issue Preston
ELVIS striation Preston

Russell Rigby and myself have made contact with ELVIS re suggested improvements and data quality concerns. We each received responses that indicate a will to continue product improvement.

Credits

Russell Rigby, ONSW mapping convenor for his experiences of ELVIS.

Geosciences Australia for releasing an easily accessible pool of LiDAR data.

NASA for the Creative Commons licenced image of 1998 storm Elvis over USA and Atlantic.

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LiDAR workflow in OCAD

Lidar contour interpretation

A generic LiDAR workflow in OCAD orienteering mapping

Orienteering isn’t mentioned amongst the 17 industry uses of Light detection and ranging (LIDaR) that Wikipedia covers. Yet LiDAR  is being adopted increasingly for our mapping. It offers a reduction in effort, sometimes significant, in both cartography and field work. Bendigo Orienteering Club, VIC was an early adopter of LIDaR and some of their experience will be covered in a forthcoming article.

So what is involved in our using LiDAR? The following 5 step generic workflow from OCAD AG gives you an insight.

1. Import LiDAR data

File formats

  • LAS (interchange format of 3 dimensional point cloud data)
  • XYX (RAW data ASCII)
  • ASCII (ESRI ASCII Grid and ESRI Grid XYZ)
  • SRMT (Shuttle Radar Topography Mission)

    Lidar ASCII GRID & XYZ
    Lidar ASCII GRID & XYZ

LAS is the preferred format if available as it is efficient and non-proprietary.

DTM and DSM

Separate Digital Elevation Model (DEM) data sets can be derived from LAS. These data sets are the Digital Terrain Model (DTM) and Digital Surface Model (DSM). These  allow calculation of vegetation height.

Tip

Different parts of DEM data can be merged in OCAD 11.

2. Derive contour lines

Contour lines can be derived at any interval. Assign LiDAR data directly to symbols of index contour line, normal contour line or form line.

Lidar contour stages
L: contours derived. R: contour interpretation

Tip

The option split in tiles, can save time in deriving contour lines.

3. Derive hill shading

Maybe not for orienteering? However, samples I have seen of relief shading at high resolution, can reveal ditches, erosion gullies and small depressions.

Lidar hillshading derived and interpreted
Lidar hillshading derived and interpreted

This functionality is likely to be very useful for trail maps.

4. Vegetation height map

This process can not only show vegetation boundaries but also vegetation stages. The latter can indicate the likelihood of runnability and even visibility. For example short, and therefore young, pines are likely to have low runnability and maybe low visibility. Is this useful in preparing for field survey? Maybe we will find out from Bendigo’s experience.

LiDAR vegetation height orthophoto and interpreted
LiDAR vegetation height orthophoto and interpreted

A practical use

A recent development in NSW has enabled detection of species using LiDAR mapping. This is to sufficient accuracy that it is saving considerable field hours in forest management including assessing fire risk from season to season.

5. Derive slopes and cliffs

A slope map can be derived. Cliffs can also be derived according to steepness. For example any slope greater than 60º might be designated as a cliff. The field mapper would then determine if it does rate as a cliff and if so, is it rock or earth. Nicely, the location is already fixed.

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LIDAR use for WOC’12 Maps

WOC'12 O map Givrin

LIDAR delivers vegetation and contours

LIDAR (Light Detection And Ranging) is known to orienteering mappers a method of develop contours and plotting various features. Perhaps few know of the application of LIDAR to plot vegetation types and boundaries.

An article published in the Swiss O magazine in 2012 described how LIDAR significantly assisted accurate elevation and vegetation cartography for WOC’12. The vegetation interpretation was the result of a joint effort between OCAD AG and the WOC mappers and that functionality is available to you in OCAD 11. You can read here the English translation, a PDF of 2pp by Thomas Gloor, CEO of OCAD AG.

Image detail

The images in the PDF image strip can be viewed in more detail by selecting the images in this gallery.

Further reading

There are two other English translated articles in the same series.

  1. Print Techniques and the OCAD Layout Layer can be accessed from my previous post Swiss Maps Swap 5 colours for 4
  2. Sprint Maps will be published in the March 2013 edition of The Australian Orienteer.

A coming post will give a snapshot of Bendigo Orienteering Club’s successful use of LIDAR. Don’t miss hot topics – subscribe to all or a selection of posts from this website via the Get Fresh with Us block in the sidebar on the right.

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LIDAR in Orienteering Mapping

LIDAR example

What is LIDAR?LIDAR example

An excellent brief description can be found on this CSIRO web page.

NZ Experience

An interesting experience of use of LIDAR in orienteering mapping was recently posted on the NZ MapTalk’s Mapping forum, pages 38-39. The linkis in the sidebar on this page but more directly, head to Selwyn’s post of 7 June on the topic of Base map contours.

Finnish experience

In that post he mentions work by RouteGadget’s developer on automating orienteering map production from LIDAR sources. For those interested in LIDAR potential, this is well worth a visit. Find it on the RouteGadget Facebook page. (You might have to be a Facebook member to view).

USA experience

A 2005 article LIDAR Basemaps Come of Age by Greg Lennon of Quantico Orienteering Club, USA. The image upper right is from that article.

Australian experience

Best experience as at late 2017 is found on the Orienteeering Australia mapping pages.