MFM Polygon Standardization Discussion

[koi]

Option 1

I've using 0x0002 (Small Urban Area) for apartment/flat compounds and 0x0003 (Rural Housing area) for most other compounds.

Option 2

all the area which surrounded with fencing I used 0x11 & all the residential building inside the area I used 0x13

Mmm ... based on colour coordination, I'm inclined to GHz's option 2 for apartment/flat compounds with multiple buildings in the area.

I am neutral on the choice as both looks okay to me.

I would like to confirm if we need to subtract the building polygon from background? I will need to revise mine polygons. Please advise?

[76gpsguy]

I am neutral on the choice as both looks okay to me.

I would like to confirm if we need to subtract the building polygon from background? I will need to revise mine polygons. Please advise?

I think it is ok with building polygon on top of background (apartment area). It is easier to edit polygons in the future if required.

[tympg]

When you use the subtract method the two polygons are no longer overlapping at all. They share a common edge/border. One could be even completely within another. Both polygons will show regardless of polygon draw priority.

Earlier on, I was advised by OngCC not to have a polygon with a hole in it, i.e. a polygon with another (smaller) polygon (completely inside the larger polygon) subtracted from it.

Apparently it messes up the compilation of the map. I'm not sure if this is the case any more.

[antyong (retired)]

Guys,

You don't have to do any subtractions. We sort the polygons by draw priority so that the appropriate polygons will be displayed on top of the other.

I also propose to use building (0x13) polygon for building block outline and leave Residential building (0x11) to cover the whole area.

I will post a detail spreadsheet tonight to facilitate further discussions


p.s. FYI subtracted polygons do not pose problem when we compile directly from mp. It was Wsian's converter to shapefiles which cannot handle complicated polygons.

[9W2CBL]

OK Antyong, looking forward your posting on the spreadsheet, and see what I can learn from you guys to build up polygon!

[tympg]

I also propose to use building (0x13) polygon for building block outline and leave Residential building (0x11) to cover the whole area.

What about single apartment blocks with no compound?

[tympg]

Guys,

You don't have to do any subtractions.

While I certainly wouldn't recommend using polygon subtraction in building-in-the-compound situations, polygon subtraction is still useful, like in the case sabelt posed earlier (park against a lake) or a another example, beach against the sea. In these latter cases, subtraction saves a lot of labour tracing nodes along an existing polygon.

[antyong (retired)]

Please refer to MFM Polygon Reference for further discussions.

[tympg]

My idea is to use colored polygons to represent the whole area. Detail building structures should be drawn with 0x13 builiding or other customised polygons. Grey shades will be the color used for detail structures.

- What about 0x10, is that a housing building or an area? (I'm thinking of some big houses along some of Penang's roads which are still occupied as residences).

- Grey buildings against dark brown Gov't areas don't look nice. (See N5.42339 E100.30934) I was actually thinking of changing that one to something like N5.41178 E100.30714

- For medical facilities, I was also thinking of changing Adventist Hospital N5.43229 E100.30512 to look more like the Dental College N5.41924 E100.30847. But it seems like the former actually adheres to your standard.

- Since 0x11 and 0x12 defines compounds/areas they shouldn't be called "Residential Building" and "Government Building" respectively any more.

- Parking Garage is US English for multi-storey or covered car park. I'm already using it in some places (eg N5.35076 E100.30842). "Parking Lot" is US English for "open car park" that means parking at open ground, not in a building.

Thanks for reading my post.

[sabre23t]

My idea is to use colored polygons to represent the whole area. Detail building structures should be drawn with 0x13 builiding or other customised polygons.

- What about 0x10, is that a housing building or an area? (I'm thinking of some big houses along some of Penang's roads which are still occupied as residences).

Antyong defined "0x10 House" as "Entire Area" in the <<MFM Polygon Reference.xls>> spreadsheet. As I understand that ...
* if the house is a bungalow with a very big area having a small building within it, I can draw a 0x10 polygon covering the whole house compound/area, and draw a 0x13 polygon defining the actual smaller building within it
* if the house is a small garden bungalow where the building is not much smaller than the whole compound, I can just draw a 0x10 polygon covering the whole house compound area, and don't bother putting in a 0x13 polygon at all.