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Author Topic: "Buildings" polygon layer  (Read 4730 times)

vt.flatlander

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"Buildings" polygon layer
« on: March 24, 2016, 06:23:19 PM »
I tried adding a "buildings" polygon layer to my map using Hex Code "0x6402" but that did not work. Is there a different code number I should be using ? It is a very small amount of data. About 5MB.

Boyd

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Re: "Buildings" polygon layer
« Reply #1 on: March 24, 2016, 06:40:47 PM »
0x6402 is the MP_TYPE for a point feature, not a polygon. ;)

See page 110 of the cgpsmapper manual.

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #2 on: March 25, 2016, 04:35:20 PM »
Woops;
After opening the PDF for all the codes I hit Control-F then filled the search box with "building" then took the first code that came up. I never looked at the top of the list.
Thanks for the clarification.
I'll try something else.

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #3 on: April 07, 2016, 07:51:32 AM »
I would like to add a "Buildings" polygon type to my map but cant seem to find a MP_TYPE Hex Code that works.
I tried 0x03 City and also 0x06  Parking Garage but neither worked.
Even if the Oregon rendered it out of the map I thought it would be nice to see the items in BaseCamp.   

Boyd

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Re: "Buildings" polygon layer
« Reply #4 on: April 07, 2016, 09:04:15 AM »
The standard types are on page 120 here: http://cgpsmapper.com/download/cGPSmapper-UsrMan-v02.5.pdf

You could use 0x13 "man-made area" I suppose. Really, I think it's irrelevant what code you use. Pick any code you like, there are quite a few that are not officially defined. In TYPVviewer just choose a code, choose a color or pattern, enter BUILDING (or HOUSE or whatever) in the description box and choose English as the language. This will over-ride the default description of the object.

If you don't give the building a name, then the gps will display BUILDING when you tap on it. Same thing in Basecamp. I use my own typ numbers that vary considerably from the standards. :)
« Last Edit: April 07, 2016, 09:06:26 AM by Boyd »

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #5 on: April 07, 2016, 09:28:51 AM »
Boyd
What I don't understand is if the hex code I use is irrelevant then why don't any of the polygons that I assigned 0x16 to show up on my map ?
I removed the "name" column from the attributes of this data before running the batch files in order to keep labels from showing up in the GPSr.

Boyd

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Re: "Buildings" polygon layer
« Reply #6 on: April 07, 2016, 10:43:41 AM »
I don't know what, but you must be doing something wrong. I have a map that mimics aerial imagery and uses every available polygon code (83, I think). This map displays exactly the same on my Montana, Nuvi, Basecamp and Mapsource (and Basecamp Mac/PC is identical too). In experimenting I only found two codes that cannot be re-purposed for whatever you like - 0x4a and 0x4b. They are used to define the map area and weird things happen if you use them for other purposes. ;)

Boyd

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Re: "Buildings" polygon layer
« Reply #7 on: April 07, 2016, 11:07:31 AM »
BTW, I have been working with building polygons pretty extensively over the past year or two, should start a thread on it here. The OSM dataset has pretty impressive coverage of buildings in the major Northeastern US cities. Looks like just about every building is included in the New York City metro area, I think there are over 1 million polygons.

I have a version of my map that includes all of these and it works really well in Basecamp, zooming and panning are almost instantaneous, even with all those polygons. But it just chokes every gps I've tried it on. Very dramatic demonstration of the power of a computer vs a Garmin GPS. So I have filtered the buildings based on calculated areas and only used a subset of larger ones. IIRC, I had to drop out everything less than 5,000 square feet to get to a manageable number that the GPS could handle.

Current smartphones have laptop class cpu chips now, so large numbers of polygons should work in apps, but Garmin's hardware is way behind smartphone quality. ;)

I have been gradually adding my own building polygons to rural areas and small towns in my area. I started a thread on GIS apps for iOS awhile ago, my iPhones 6s Plus is a pretty nice platform for working on this kind of map detail when I'm waiting for something and need to kill some time. :)

« Last Edit: April 07, 2016, 11:10:38 AM by Boyd »

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #8 on: April 07, 2016, 12:28:48 PM »
Boyd
I'm using a data set that I believe is from an OSM source even though I pulled it off VCGI.
Vermont Center for Geographic Info.
The state population is approx. 600,000 people so it is extremely rural throughout most of the state. The data set I am using is not nearly complete but I thought it would be interesting to see what it looks like in my Vermont Topo map.
So far no success in getting the polygons to show up on my map. The data looks fine when viewing the map in QGIS. It is somehow getting lost during the compilation ?
I'll keep trying .

Also
Both of those map images you provided look amazing !
« Last Edit: April 07, 2016, 12:31:23 PM by vt.flatlander »

popej

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Re: "Buildings" polygon layer
« Reply #9 on: April 07, 2016, 12:57:05 PM »
Do you include TYP to your map? If so, then you have to set drawing order in TYP for each polygon type you use.

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #10 on: April 07, 2016, 02:53:45 PM »
Thanks popej

I will look into this as I have an included .tpy file but was unaware of setting the draw order for each polygon type.

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #11 on: April 08, 2016, 07:48:31 AM »
Ok
I can see that my "Buildings" polygons are on my map. I had to zoom to the highest level to see that they are there.
I need some guidance how how to set draw order.

Boyd

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Re: "Buildings" polygon layer
« Reply #12 on: April 08, 2016, 08:38:07 AM »
Then it probably isn't a draw order issue. But here's how to set it: just fill in the number in the DrawOrder box at the top of the window when you create or edit a polygon in TypViewer. Draw order can only be set for polygons, not lines or points. Lines and points are always drawn on top of polygons in Garmin's system.

Higher draw order objects will cover lower objects. There is also the Draw Order box at the bottom left of the main TypViewer screen where you can view/edit the order of all polygons.

For the conceptual part, see the section starting on page 33 here. TypViewer gives you a graphical user interface so that you don't have to edit text files or compile them: http://cgpsmapper.com/download/GM8DocV2.pdf

If an object doesn't show until you zoom way in, that sounds like a zoom level issue and that is another complicated matter. ;) On a gps device, you would not want buildings to show when you zoom out very far. As mentioned above, a large number of buildings will just choke the gps, often causing a crash/freeze.

Also note that the detail menu setting will affect what shows in both Basecamp and the GPS. Set it to the highest level and see if that changes the behavior.
« Last Edit: April 08, 2016, 08:41:05 AM by Boyd »

vt.flatlander

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Re: "Buildings" polygon layer
« Reply #13 on: April 08, 2016, 10:01:44 AM »
Boyd
It took me a minute but realized I was using the wrong MP_TYPE code in my .typ file.
I now see the buildings but oddly enough all the polygon building shapes are really strange. Nothing square or rectangular as you would expect a building to look like. Lots of odd angles.

Boyd

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Re: "Buildings" polygon layer
« Reply #14 on: April 08, 2016, 10:45:58 AM »
Should have mentioned before, the accuracy of Garmin's map format is limited to about +/- 2.5 meters (about +/- 8 feet). This is not good enough to accurately represent an object the size of a house, for example.

Just imagine what a building would look like if the carpenters constantly made mistakes as large as 16 feet? ;)

But just zoom out to a reasonable level, like .2 miles and it will look pretty good. Try looking at a "real", paper USGS 1:24000 topo map with a magnifying glass. Features like buildings are only rough approximations.