Posted on Leave a comment

Lidar & Overlapping UTM Zones

Second zone DEM imported

by Rob Plowright

Intro by Ken: Other than Tasmania & ACT, all states & territories have 2 zones. NZ has just one zone. I recall struggling with marrying datasets from 2 zones for a map that was close to the edge of 54/55. So Rob’s experience will be valuable for the few who are faced with this issue. The general process will also apply to other types of data.

Coping with Australia’s 4 zones

Now that didn’t work

The other day I was doing some virtual exploring: processing lidar in OCAD to see if I could find some interesting terrain. One area I was interested in just happened to be on the boundary between UTM zones 55 and 56; first time I had experienced this. Getting adjacent lidar tiles from different zones to line up in one OCAD file proved to be more difficult than expected. After trying several different approaches and getting nowhere I finally managed to do it, with the help of a suggestion from Ken.

This involved processing the tiles in one zone then using Map > Transform > Change Coordinate System to change the map into the next zone, then processing the remaining tiles. There was one problem however: while the map (contours) transformation went well, the background images (hillshade, vegetation, etc)  did not.

Ken asked me to write-up the process for his up for his blog. Since there was the problem with the background images not transforming properly I sent the first draft to OCAD support. Gian-Reto got right back to me saying that while the method I described would work, there was a quicker way – just using the DEM Wizard. “That’s odd” I thought, “I tried that and it didn’t work”. Gian-Reto soon figured out there was a bug that meant southern hemisphere UTM zones did not process properly and he promptly fixed it.

So just in case anyone wants to know, here is how to do it.

The works

The lidar coverage

I will use an example from Kanangra in the Blue Mountains (not the area I was looking at – which shall remain secret for now).

  • I have five lidar tiles: two in zone 55 and three to the east of that in 56. They are:
    • Taralga201611-LID2-C3-AHD_7746232_55_0002_0002
    • Taralga201611-LID2-C3-AHD_7766232_55_0002_0002
    • Burragorang201805-LID2-C3-AHD_2226232_56_0002_0002
    • Burragorang201805-LID2-C3-AHD_2246232_56_0002_0002
    • Burragorang201805-LID2-C3-AHD_226232_56_0002_0002

As you can see from the double digit components above, the Taralga tiles are in zone 55 and the others in 56

Each tile is 2km x 2km and the numbers after ‘AHD’ give you the grid reference for the SW corner of the tile. So the  SW corner of the first Taralga tile is at 774000 6232000. and the first Burragorang tile is at 222000 6232000  You will notice that the Burragorang tiles have the same northings (6232000) as the Taralga tiles but different eastings.

1. Select co-ordinate system

The area is mostly in Zone 56 so I have decided to make the OCAD file zone 56. Set up a map in zone 56.  First process the zone 55 (Taralga)  tiles. (You could just as easily do zone 56 first).

Select co-ordinate system
Selecting co-ordinate system

The map now looks like this.

Lidar image
Lidar image first zone

Contours (5 and 25m)  are in grey and vegetation height is in the background (I have not bothered rotating the map to magnetic north for this exercise). The blue border shows the OCAD DEM boundary (which is oriented to zone 56)  but I have drawn in the actual boundary of the Taralga tiles’ data with the purple dashes. As you can see the Taralga tiles are sightly rotated relative to the Burragorang tiles, as you would expect since they are oriented to zone 55.

Looking closely
Rotation artifacts

If you look closely there is a little bit of junk in the gaps between the OCAD DEM and the actual (rotated) Taralga tiles.

2. Processing the other zone dataset

Now process the Burragorang tiles – but this time, in the DEM Wizard, make sure it says zone 56 for the DEM tiles.

DEM import next zone
Setting co-ordinate systems for next zone

Now the map looks like this…

Second zone DEM imported
Second zone DEM imported

I have made the Burragorang contours red for the sake of this exercise.

If you look closely at the above image, you can see that there is a large overlap between the westernmost Burragorang tile and the easternmost Taralga tile; almost a whole 2 x 2km tile. It is not always this much. In the area I was looking at before, it was only about 500-600m.

Also in the close-up below, you can see that the red and grey contours  are not exactly the same. This is because the two lidar sets are from different flights: Taralga 2016 and Burragorang 2018. In the other area I was looking at, both lidar sets (zone 55 and 56) were from the same year, and obviously from the same flight, as they matched exactly.

Difference in contours
Close up of difference in contours

The red contours above are more detailed (noisier) as, being more recent, that lidar is higher resolution. If  this map is just for a base map the slightly different contours is not necessarily a problem. But if you want to eliminate the overlapping contours you can crop one set.

3. Eliminate overlap

Since the Burragorang contours are more recent I am going to crop the Taralga contours. Start by hiding the Burragorang (red) contours and draw an area (light blue in this example)  over the parts you want to crop. Then use the Object > crop objects tool. You can also draw the cropping area so as to remove the junk around the edges.

Cropping the overlap
Cropping the overlap

And I get this…

Cropped overlap
Cropped overlap

Unhide the red contours to get this…

The full picture
The full picture

Up close the border between the zones looks like this…

Close up of the join
Close up of the join

Tips

  1. This process, excluding the DEM aspects, can also be used for non-lidar datasets over 2 zones.
  2. If you are new to lidar processing then download one of my DEM templates for use with the DEM Import Wizard. The template has 15 differentially coloured symbols to cover each of the contour selections in the wizard and to avoid confusion with any brown contours in your main or background map. Get one at ocad.com.au/mapping-resources
  3. If you have distortion in a small area, check out Map > Transform > Local transformation. It makes the adjustment of existing maps to geo-referenced base maps (hillshading, orthophotos etc.) easier and more accurate.
Posted on Leave a comment

KML Export to MapRunF

For OCAD 12 and earlier version users

The latest OCAD blog announced that OCAD subscription editions now provide a straightforward process to get your maps and courses onto MapRunF.

Starter edition is your low cost route to this simplified process. Plus OCAD Australian and New Zealand buyers can take advantage of a lower price for 3 year subscriptions. Head to ocad.com.au/shop for pricing.

From the blog

To upload maps and courses to MapRunF, you need to export…

The full post is ocad.com/blog/2020/12/orienteering-with-virtual-controls/

Posted on Leave a comment

Issue with Double lines edit

Issue with editing double lines symbol

Experiencing unexpected behaviour when editing a double lines symbol in Orienteering edition?

Michael Wood, NZ reported that when editing the symbol, sometimes the Fill colour details are greyed and it could not be ticked or unticked. Also the Mode field is blank.

If this is a nuisance for you, then you can download and install a fix pending the next OCAD Orienteering update.

Tip re adding text from a database

Recently i imported a Shape file and added spot height symbols to a trail map. Then I selected Database > Add text from database records in order to place the actual heights adjacent to the symbols. However every height was identical.

Eventually I consulted OCAD Inc support and I discovered that selection of a unique key when importing sashape file is very important. Usually the key presented to me in VicMap shape files is PFI or UFI so i hardly look at it. However this time a different key showed and I simply accepted it.

However it turns out that for some operations, the key field must have unique entries in the shape file. In this case, to deliver the text that matched each spot height instance.

Still learning.

Posted on Leave a comment

OCAD $, Tips

Covid-19 & OCAD | GPX import |
OCAD georeferenced satellite images

Beating Covid-19 impact

Personal and club funds may have taken a beating from Covid-19 avoidance measures. So here are two small but hopefully useful OCAD Aus/NZ initiatives in respect of OCAD pricing.

Firstly, 3 clubs in SA demonstrated a fast and effective way of taking advantage of discounts. They banded together as an informal ‘OCAD SA’ group and placed an order for 5 Orienteering Teams licences. Due to the process for managing Teams licences, each club is able to totally manage their allocation even though the licences are in the name of the group. The group ‘leader’ can place the order online in the Shop.

Secondly, for the remainder of 2020 or the end of the Covid-19 travel restrictions in AustraIia/NZ, I will continue to apply the 15% discount for 3 year terms. (The official discount reduced to 10% on 1st April). [correction to original post]

GPX file import changes

ADD Import, GPX: Assign symbols directly from <sym> node in Oribooklet gpx.

from March 2020 service update

The problem

This displays the symbol name assigned by the mobile orienteering app Oribooklet. Great idea but maybe not for the majority who get their GPX files by other means. The symbol name is obtained from the Symbol column in many GPX files. So non-Oribooklet users will generally find the POI number showing as usual but now alongside will be the word ‘POI’ or ‘waypoint’ or similar.

This has been reported as showing in a large text on import. In my test at right, it is shown in a very small text – prior to conversion to a text symbol, at approx. 3pt. Yet still very confusing.

Solutions?

So maybe this is a good time to suggest further improvements the GPX import.

  1. On import, only display symbol name/symbol if OriBooklet is identified in the GPX file header.
  2. or make it an option to display/or not, the Symbol column content.
  3. On import, provide an option to display any Comments column content – OruxMaps users may find this useful.
  4. Add to the existing import GPX selections, an option to select a text symbol to display such text.
  5. let me know of any further suggestions to put forward.

Download georeferenced satellite images

Did you know the OCAD acquisition of georeferenced satellite imaging is now quite easy? Neither did I until I stumbled across the OCAD wiki entry for Download georeferenced satellite images. And I was surprised at how easy it is and of a suprising quality.

VicMap roads with imported Google satellite image in background. Very good concordance.
Export from OCAD of import result. Red lines are VicMap roads in my georeferenced map

Read my knOCAD post for further explanation of some of the OCAD wiki instructions.

Off course

Orienteering can heartfully say vale to Gary Starkweather, the inventor of the laser printer at Xerox. That invention was, and is, a lifeline for orienteering in small O populations as it;

Laser printer decomposed
By KDS4444 – Own work, CC BY-SA 4.0
  • reduces the cost of printing (early this century O maps were offset printed)
  • avoids the mark up of map changes – a source of error
  • avoids the mark up of courses – another common source of error

Gary continued development of the laser printer technology despite his Xerox boss telling him not to. Eventually it won a 3 way test of printer technologies at Xerox and came on the market in 1977, a huge success for Xerox.

Washington Post via The Age

Posted on Leave a comment

New OCAD features roll on

Uncertain about an OCAD subscription?

per March 2020 Australian Orienteer

Still uncertain whether to update from OCAD 11, 12 …? Check out these 2020 new features on top of those above, then head to ocad.com.au/shop.

  • Starter edition: now has Layout functionality to apply logos, legends, MN symbols, scale bars, print marks.
  • Course setting: also now has Layout functionality.
  • Preferences: Set default co-ord system.
  • Oribooklet users: Import GPX symbols assigned from Oribooklet. (A great app for smart device mapping).
  • DEM: TIFF DEM import.
  • Course Setting: Import courses and classes from csv/txt including number of runners and comment.
  • Export PDF: Support Geospatial PDF (WGS84) for georeferenced OCAD maps. Note, as yet these are not suitable for Avenza publication so continue to use world TIFFs.
  • Load symbols & colours, option ‘Add’: Uses added colour’s number if the number doesn’t exist in target colour table.
  • plus improvements to Legibility checks, Symbol sets, ISM conversions.
  • more to come including sketch layer for mobile.

1 year or 3 year subscription?

If you are teetering on the choice then here is a heads up. On 1st April 2020, the discount for 3 year subscription will reduce from 15% to 10%. ocad.com.au/shop.

OCAD subscription users

Temporary Backups

OCAD recently published a reminder re the availability of a temporary backup of your session. That setting is in Options>Preferences>File.

While you are there, select Help and check out the other useful options. Then take a look at Options > Back up and Restore Options. This allows you to save your Preferences and Shortcuts – very useful if you need to reinstall your OCAD or move to a new PC.

Do read the change list when updating

You load OCAD to work on a map and perhaps take an offered update right then. I suggest you don’t decide to read the list later. You are likely to forget and may overlook something important such as this change in the March update;

CHANGE Symbol Sets, Orienteering: Order of colors for ISOM 2017-2 and ISSprOM 2019 symbol sets improved.

Don’t get caught out.

OCAD 11 users

If you make use of your 2nd activation, or any activation after a reinstall, then please use the website activation method.

When you start the activation process in OCAD 11, you can choose between the option ‘Online Activation’ or ‘Website Activation’. http://www.ocad.com/howtos/online_activation_ocad_11.htm http://www.ocad.com/howtos/website_activation_ocad_11.htm The ‘Online Activation’ is not working any longer.

ISOM 2017-2 colours too weak for digital print?

Has the move to ISOM being expressed in CMYK rather than Pantone, been successful? Not entirely.

Some users are finding colours such as blue (lighter) and purple (magenta) to be inadequate in some situations. This is more likely to be true of MTBO where we are unable to bring the map closer to our eyes.

Provided you aren’t creating maps for an international event, you could consider the Swiss Frey colour palette. This is an update of a palette brought out 3 or 4 years ago to provide a more accurate colour rendition for digital print. The first palette was developed on a Xerox Versant, the latest on a current model production level Konica Minolta. Another colour of relevance to MTBO is line brown for contours. The Frey swatch has a dark brown which is very close to the brown Jim Russell and I developed for MTBO digital print some years ago.

The palette has colour numbers consistent with the ISOM 20187-2 palette. Thus using Map > Colours > Select colour swatch > Load colour swatch > ISOM 2017 Color Swatch Frey Digital Print makes it easy to change your ISOM palette to the Frey palette in whole or by moving specific colours. View an English translation of the German.

ISMTBO blues are close to the Frey blues. However you might like to use the Frey brown for lines (15 Braun 100% – Linienobjekt’ 30,70,100,0) to provide more legible contours. If using Load colour swatch to make the change, ensure you untick the 3 options at lower left of the swatches.

You might like to first print, on your intended digital press, this sample pdf of the Frey palette. The German/French sub-titles at left on the pdf translate as ‘Print Resolution’.

Off course

Thank Gladys West for your GPS capability

Gladys West poster

In A Mathematician Idolised, Cosmos magazine gave a brief account of Gladys West’s significant contribution to the Global Positioning System (GPS) that mappers are increasingly using. Gladys was a key developer of the first highly accurate geodetic earth model (geoid), that was the basis of the GPS.

More recently Cosmos expanded on that item with Science History: Gladys West Maps the Future.

If you watched the film or read the book Hidden Figures, Gladys West is a contemporary of those women. While they worked for NASA, she worked for the US Naval Weapons Laboratory. However, she was equally embraced by Air Force Space Command with her induction into the Air Force Space and Missile Pioneers Hall of Fame.