US Forest and Swamp data

[Nule]

Hello!
Where can I download US Forest and Swamp data for my custom map?
Thank!

[z_statman]

Can you be a bit more descriptive? There are topo maps that do what I think you might be asking for but unclear

[Nule]

I'm trying to make a topo map for Garmin based on USGS and Tiger data. But I I don't have forest and swamp data

[Boyd]

Do you want land cover data (shaded areas that show where forests are)? That can be hard to come by. My state (NJ) has excellent high res land use/ land cover data available at 1:12000. But this seems to be the exception. None of the other states I've look at have this. But try some google searches using "LULC" as a key word along with "GIS" and your state's name. You can see what the NJ data looks like in my NJ 2012 map: http://www.gpsfiledepot.com/maps/view/294/

I have developed my own system for converting LANDSAT raster land cover data into vector data for use in my maps. Wrote about it some time back here: http://forums.gpsfiledepot.com/index.php/topic,1693.msg10193.html#msg10193

There were some flaws in my methodology there, but I have corrected them and now have a system that works well. One of these days I will get back around to writing about this and making some maps using it. But for now.... "so many maps, so little time"  It gets complicated. It also will make your map files very large since you end up with lots of polygons.

Regarding swamps, that's another pet project of mine since I live in a low coastal area that has extensive wetlands. That data is part of the NHD (National Hydrology Database) and is available for the entire US. But unless it has been updated, if you follow the mapmaking tutorial on this site for using NHD, you will end up discarding the wetland data. Therefore, if you look at many (most?) of the maps on this site, no wetlands are shown.

I have again developed my own techniques with a relational database for classifying NHD data that retains the information about wetlands. There would be other ways to do this also of course. But anyway, the wetlands data is all there if you download the high res NHD, but you just have to extract it. Sorry, but I would need to refresh my memory on this in order to be more specific. I can do that later if nobody else chimes in first.

[maps4gps]

I'm trying to make a topo map for Garmin based on USGS and Tiger data. But I I don't have forest and swamp data.

Nule and others: Please provide area of interest in your posts.  Available data can differ greatly by area. 

Nule: Swamp/marsh is coded H2025 in the TIGER data.  The forest/woodland layer is the most difficult layer to digitize.  I am not aware of a source which digitized this info on a National level.  Some State GIS office, etc.  may have done so.

if you look at many (most?) of the maps on this site, no wetlands are shown.

Boyd:  past time for new glasses

I use GM and dbase and include NHD codes 46600, 46601 and 46602 (State topos) and TIGER H2025 (regional planimetric) - wetlands/swamp/marsh. 
As the author of most of the State topos, I find (IMHO) that statement very inaccurate and misleading.

Also consider the differences in:
Definition of wetland as used by USGS and others for printed map products
versus that used by biologist in the National Wetland Inventory database
versus what can be accurately classified with a 30m pixel size in the LULC data set.
Differences in age of the source data.

[Nule]

Many thanks!
How can I download TIGER H2025?  I don't see anything like H2025 on census.gov/cgi-bin/geo/shapefiles2011/main
I don't understand what means this codes.

[maps4gps]

H2025 is the feature code for swamps/marshs.  They are in the areawater files.

That interface is going to be very slow going if you are wanting the data for more than a few counties.

[Seldom]

Nule,
From Boyd:

I have developed my own system for converting LANDSAT raster land cover data into vector data for use in my maps. Wrote about it some time back here: http://forums.gpsfiledepot.com/index.php/topic,1693.msg10193.html#msg10193

The really interesting part of this thread starts on January 15, 2011, when Boyd points out that Global Mapper 12 has a way to vectorize raster TIFFs.  That permits National Land Cover Datasets (georeferenced TIFFs) to be converted into vector graphics based on the color of the grid segment.  The grid colors differentiate evegreens, deciduous, mixed growth, scrub, and a number of non-vegetated surface types (like paved).  Alas, GM isn't cheap, but if you buy it, I (and probably others) can share scripts that can automate the vectorization process.

Also, Boyd, re. swamps, if they're in UT, AZ, NV, or my slices of NM, CO and Death Valley, my map's probably got them.  Just not very many swamps where I live.

Nule, it would help if we knew what mapping software you are using.

[Boyd]

Boyd:  past time for new glasses

Haha, actually you're right about that.  My Windows machine is offline at the moment while I remodel the room it's in. But last time I looked at your NJ topo, it had far fewer wetland areas than my own map. That was a couple years ago, so maybe it has changed now? When I get my PC back online I'll take another look.

Personally, I discard everything but the roads from TIGER data because the water data has always seemed very incomplete when I've looked, and the NHD data is much better.

Yes, the Globalmapper function to create polygons from raster data is the way to go if you want to process LANDSAT imagery. However when you couple this with the power of a relational database such as FileMaker Pro, it really streamlines the process. As I said, I'll post more about this eventually.

I have also considered creating some forest cover maps for different parts of the US and making them available to other mapmakers. Would that interest anyone? If so, what format would be good? I have thought that regular Garmin .img files might be the way to go since that's mostly what this site supports. They could be converted back to .mp with GPSMapEdit.

[Seldom]

I have also considered creating some forest cover maps for different parts of the US and making them available to other mapmakers. Would that interest anyone? If so, what format would be good?

I guess IMG files are smaller, hence easier to make large areas than MP.  I wonder how you would tile them?  I suspect that everybody who uses them is going to want different boundaries.  Also, the IMG files might be useful on a GPSr if they were transparent, but they wouldn't be too useful all by themselves in BaseCamp.

[Boyd]

They could certainly be transparent, but that probably isn't going to add much since polygons on a transparent map will hide everything beneath them. As far as boundaries, would have to look more closely but I was thinking along the lines of using 100k quad boundaries since the LANDSAT data is relatively low resolution and would probably produce reasonable tile sizes. If somebody already knows how to make maps, slicing and dicing these as needed would be pretty trivial.

What I'm contemplating would really only be useful for mapmakers though and I wouldn't include a mapsource installer. The idea would be to encourage other mapmakers to include forest cover, which is something that's sorely missing from Garmin's own maps. For example...

[maps4gps]

Boyd,

    The situation is: the NJ topo uploaded in May/June 2011 uses 24k NHD; the State topos I
made available in Feb/March 2009 used TIGER hydro as they were intended to be 'temporary'
until others could become involved and share their creations (except for your NJ topo, that has not happened).