Small Control Circles

[buzz]

From the major events newsletter....

Since ISOM 2017 overprint sizes, north line separation and symbol sizes were standardised so that their sizes relative to the terrain is consistent, and whilst mappers have adopted the standards, planners often use non-standard overprint sizes which causes various problems.

Many planners aren’t aware of the ISOM specifications and use the default settings in course planning software. Unfortunately Purple Pen reduces the overprint sizes for 1:7,500 scale maps by default so planners are inadvertently using non-standard sizes. The workaround is to set the Event->Customise Appearance ->Scale Item Sizes option to 'Relative to 1:15,000'

Some planners deliberately reduce the overprint sizes and this practice is backed up by a BOF guideline:

“2.3.9 When 1:7500 maps are provided, the course overprint symbols, and text can be the same dimensions as for 1:10000 maps (i.e. a 150% enlargement of the ISOM symbols). This improves course clarity but may require changes to control descriptions.”

Small control circles can potentially cause a number of issues:

Smaller circle sizes tend to obscure important detail in the vicinity of the control (less clarity not more!)

If multiple scales are provided each scale may need different circle cutting and control descriptions (more work and potential for errors).

Control circle size is an important cue for judging distances on the map. Small circles tend to make controls look further apart.

Small circles encourage planners to use more controls on courses – often to the detriment of the course.

Small circles encourage planners to position controls too close together on the ground.

Presumably when the BOF guideline says ‘improves course clarity’ it is referring to cases where courses with complex shapes or confined to small areas and nearby circles and control numbers obscure important features. If that’s the case then rather than change control size planners could consider:

Using double sided maps with the course in two parts.

Use smaller control numbers but leave the circle size etc. as standard.

One exception where small control circles might be appropriate would be on TD1 or TD2 courses where more controls are sometimes required to meet course planning guidelines.

[pete.owens]

I think the default in purple pen is to scale relative to 1:15000.

The other thing to remember if you are fiddling with circle sizes for 1:7500 maps is that the diameter in purple pen specifies the outside of the circle, whereas ISOM specifies the centre of the purple line - so you have to add the line thickness.

[buzz]

I think the default in purple pen is to scale relative to 1:15000.

The default for 1:10,0000 and 1;15,000 is 'scale relative to 1:15000', but the default for 1;7,500 is 'relative to map scale' at least that's what I get when creating a new event in version 3.5.2 which I thnk is the latest version. I'm not an expert though - I use CONDES so let me know if you see something different.

[rf_fozzy]

This is also an issue if planning an ISSprOM event - Purple Pen defaults to Circle sizes that are too small and you have to manually adjust.

For night events, I tend to increase the circle size even more than as set in the specs. And increase line thicknesses.

If you do this, it is then possible to cut circles and lines properly - something that is frequently not always well done.

[rf_fozzy]

(btw, I believe Peter Golde knows about this and there is a reason why it does what it does).

[pete.owens]

Purple pen does ISSprOM correctly.
Circles at 6.35 mm with 0.35 mm lines at 1:4000 - and scales to map scale.

Circles would be too small if you were to shrink the scale below 1:4000, but ISSprOM does not support that - only enlargement. I guess if you were planning an urban event on a 1:5000 map then you could select the old ISOM 2000 standard with no scaling - that would give 6 mm circles.

[buzz]

(btw, I believe Peter Golde knows about this and there is a reason why it does what it does).

Yes, I saw a forum post where Peter described how he deliberately set the default small circles for 1:7,500 when ISOM 2017 came in because he didn't like the larger circles, but he didn't give a reason and seems to have ignored subsequent requests for the default to match ISOM 2017.

Hopefully once planners and controllers are aware of the issues and the workaround we'll get standard circle size more consistently. It would be great if clubs could update their user guides for Purple Pen to inlcude this advice.

Hopefully BOF rules can be amended to at least clarify where it might be appropriate to use small circles or ideally get rid of the rule altogether. Certainly major events should use ISOM standards.

[pete.owens]

Purple pen does ISSprOM correctly.
Circles at 6.35 mm with 0.35 mm lines at 1:4000 - and scales to map scale.

Circles would be too small if you were to shrink the scale below 1:4000, but ISSprOM does not support that - only enlargement. I guess if you were planning an urban event on a 1:5000 map then you could select the old ISOM 2000 / ISSOM 2017 standard with no scaling - that would give 6 mm circles.

[pete.owens]

I think the default in purple pen is to scale relative to 1:15000.

The default for 1:10,0000 and 1;15,000 is 'scale relative to 1:15000', but the default for 1;7,500 is 'relative to map scale' at least that's what I get when creating a new event in version 3.5.2 which I thnk is the latest version. I'm not an expert though - I use CONDES so let me know if you see something different.

Curious - I just tried it and that is indeed the case. I think in all the cases where I have printed maps at 1:7500, I have been using base maps at 1:10000 so it all came out correctly.

It seems very odd that the programme should behave differently depending on the scale of the base map.

[rf_fozzy]

Purple pen does ISSprOM correctly.
Circles at 6.35 mm with 0.35 mm lines at 1:4000 - and scales to map scale.

Circles would be too small if you were to shrink the scale below 1:4000, but ISSprOM does not support that - only enlargement. I guess if you were planning an urban event on a 1:5000 map then you could select the old ISOM 2000 standard with no scaling - that would give 6 mm circles.

ISSPrOM2019-2 specifications states control circles should be 6.0mm with 0.35mm thickness lines at 1:4000.

https://1drv.ms/b/s!As4LDA11gDVmg4hWeTkOofphhEyfEQ

(link to document on IOF site).

However 6.0mm is too small. For most events I find 6.35mm is too small too and usually use 7.0mm with increase in line thickness to 0.45mm.

And I use the recommended bold control numbers with 0.15mm white border line.

I also tweak the purple from the ISSprOM specs to make the contrast a little clearer.

(if you ran at Leeds University in the summer you got these tweaks on your maps - I suspect no-one noticed!).

[rf_fozzy]

Sorry the link to the pdf doesn't work.

But try the O-map wiki page instead: https://omapwiki.orienteering.sport/sym ... l-point-2/

[pete.owens]

Purple pen does ISSprOM correctly.
Circles at 6.35 mm with 0.35 mm lines at 1:4000 - and scales to map scale.

Circles would be too small if you were to shrink the scale below 1:4000, but ISSprOM does not support that - only enlargement. I guess if you were planning an urban event on a 1:5000 map then you could select the old ISOM 2000 standard with no scaling - that would give 6 mm circles.

ISSPrOM2019-2 specifications states control circles should be 6.0mm with 0.35mm thickness lines at 1:4000.

Quite - And this is what purple pen correctly uses as a default

However 6.0mm is too small.

No it is correct.

You may have a personal preference for oversized circles, but you cannot expect planning tools to default to ISfozzyOM, rather than the internationally adopted mapping standard. Particularly as it seems that the author of tool appears to have a preference for undersized circles, which is causing the problem outlined by the OP.

Purple Pen does allow you to override the appearance of the overprint. While there may be good reasons why planners may choose different sizes, colours or thicknesses the default really ought to be the appropriate international standard.

[rf_fozzy]

Quite - And this is what purple pen correctly uses as a default

However 6.0mm is too small.

No it is correct.

Nope. Go test it. Purple Pen uses Control Circles of 6.35mm diameter and 0.35mm width by default if you select the ISSprOM2019 option.

I have purple pen 3.5.2

So if you want IOF size, you have to adjust down to 6.0mm

But that's silly. Both 6 and 6.35mm are too small. I would use a 7.0mm diameter and 0.45mm line thickness for all 1:4000 and 1:5000 ISSprOM events.

For 1:3000, I'd increase the control circle size to 8mm by scaling up proportionally.

I'd have to check, but I think this is what we did for the British Sprints in 2022.

[rf_fozzy]

IIRC the increase of line thickness to 0.45mm (as well as the bold numbers and white outlines) are in Bruce Bryant's BOF amendments to ISSPrOM2019-2 specs.

The increase in control circle size is not, but it is a clear benefit.

[pete.owens]

Quite - And this is what purple pen correctly uses as a default

However 6.0mm is too small.

No it is correct.

Nope. Go test it. Purple Pen uses Control Circles of 6.35mm diameter and 0.35mm width by default if you select the ISSprOM2019 option.

Which is correct.

That is because ISSprOM specifies the diameter from centre line of the purple lines, whereas the dimension in Purple Pen is to the outer edge of the lines. This means that you need to add the line width to the diameter you want.

In the case of ISSprOM to render 6.0 mm circles and 0.35 mm lines then you need to specify 6.35 mm diameter in Purple Pen (6.0 + 0.35 = 6.35)

In the same way for ISOM 2017 Purple Pen uses a diameter of 5.35 mm to render 5.0 mm circles correctly.

And these dimensions will be scaled correctly if you print courses at different scales (unless your base map is at 1:7500)