The Moon is Waxing Crescent (11% of Full)

Welcome! Log In Create A New Profile Recent Posts
Tenaya Lake, Yosemite National Park


Forest service launches Interactive Visitor Map (IVM)

All posts are those of the individual authors and the owner of this site does not endorse them. Content should be considered opinion and not fact until verified independently.

Forest service launches Interactive Visitor Map (IVM)
May 26, 2014 08:11PM
Here is the link to the new US forest service Interactive Visitor Map (IVM):

After missing at least two earlier release dates this new map from the forest service has finally gone ‘live’. Since I have been producing my own version of maps showing forest service data, I have known for some time that the interactive visitor map was in the works. However, like the forest service, I have kept mostly quiet about it. Now that the IVM has launched, I have some thoughts to share.

You should be able to zoom in on a national forest and at some point red clickable symbols will appear for campgrounds, trailheads and various other recreation features. It worked this morning but this afternoon (hmmmmm....with more users online?) those red symbols have stopped appearing on the map.

OK, if the IVM is not working when you read this, here is a screen shot I took showing the Mason Lake trailhead and surrounding area in the Mt. Baker - Snoqualmie National Forest, Washington State. The base map is a scan of an older USGS topo map.

Obviously, this is not a Google-based map. Instead, this map is based on a product called ArcGIS Online from the ESRI company which is, by far, the largest vendor of GIS (geographical information system) software. Since the USDA (includes the forest service) negotiated an ‘enterprise’ license with ESRI, we can expect to see more of these ESRI-based maps in the future.

GIS-based maps consist of two things. First, there is a basemap which you can change. One of the basemaps the IVM can display are scans of the USGS topographic maps that ESRI is hosting. Those scans are medium resolution and have not been updated with scans of newer USGS topos.

Second, GIS-based maps have one or more layers of data that are stacked on top of the basemap. Each different kind of thing you see on the IVM (symbols, labels, shading on forest service land, etc) is a different layer of data that is hosted on a GIS server. A data layer can be transparent, semi-transparent or solid. Typically you can click on a data layer and get more information. In GIS-speak that information is referred to as “attributes” of the thing that you clicked on.

As you play with the IVM you will quickly notice a 5 to 10 to __ second lag before the data layers on your screen refresh. This happens when you change the area you are looking at by panning the map or zooming out. The code that runs the map has to make a trip to one or more GIS servers in order to get the data to display on your screen. Obviously the design philosophy for the IVM did not include the concept of caching any of this data. This seems odd to me since (1) round trips to servers slow down the user experience and (2) the data being displayed does not change rapidly. Time will soon tell what the response time will be once many people find out about the IVM and the load on the servers goes up.

Let’s think some more about all those trips to the GIS servers to refresh your screen. Those GIS servers are run by ESRI software. Everything you do with ESRI software costs money. Would it cost the taxpayers less money to operate the IVM (and of course also speed it up) if that application cached some of its data instead of having to repeatedly fetch chunks of data from the servers as you play with the map?

You can click on any GIS data and get a popup with more information. Try clicking on a red recreation symbol and then scrolling to the bottom of the popup. Under “Website” you will see a link to a forest service detail page for that feature. These forest service detail pages often have lots of useful info. Links to these detail forest service pages are a great feature of the IVM.

Some national forests include data showing which forest service roads are open to which kinds of motorized use. For example, look at the Colville forest in northern Idaho. If you zoom in and wait, eventually a layer of road data appears. You can click on a road for more information.

Alas, the interactive visitor map does not show any non-motorized trails. This seems quite odd to me since I know the forest service has that trail data and could easily display it on their map. Last summer I downloaded the forest service non-motorized trail data from their GIS server for all the national forests in Washington, Oregon and California. Then I reprocessed that data into a more useful form, cached it in the form of KMZ files and produced one map for each forest in these three states. The forest service then tweaked their GIS server so the non-motorized trail data became no longer available to the public.

Yes, some of this trail data is wrong and the data for some forests is incomplete. But this non-motorized trail data is a lot more good than it is bad. And like any large dataset, this trail data will never be perfect. Given that they have data in hand for non-motorized trails it is simply baffling why the forest service would make the decision to show motorized trails on the IVM (for some forests) but not show non-motorized trails for any forest.

If you would like to see the maps I made with the forest service trail data, please go the Gmap4 ‘examples’ page:
Look down just a bit and you will see a link to the maps I made for the national forests in Washington, Oregon and California.

Also, if you are looking at a recreation feature on the IVM and somewhere in these three states, then you can easily find the same spot on the national forest map I produced that shows the non-motorized trail data. Click on the red recreation symbol on the IVM and copy the coordinates from the popup. Open my map for that forest. After the map loads its data, click Menu ==> Search. Paste the coordinates into the search box at the top of the screen and then click search. To see a high resolution topo map, change the basemap to “t4 Topo High”. To find out more about the map I produced, click the “Tips” link in the upper left corner.

You may also notice that the IVM does not generally show ranger district offices. I inquired about this and was told that the data that was loaded onto the forest service’s GIS server did not include accurate coordinates for the forest district offices. Strange but true. Since the forest service wants everyone to buy a ‘travel map’ showing which roads are open/closed, you would think it would be in their own best interests to make the district offices easy to find by putting them on the IVM so people could buy maps, etc.

Finally, if you are GIS savvy (or simply curious), here is the link to the forest service GIS data:
The production data (i.e. forest service says “authoritative”) is under EDW.
The draft data is under wo_nfs_gstc.

Anyone can easily see the kinds of information (i.e. attributes) the forest service has in its GIS for various things. For example:
1. Open the above ‘services’ link.
2. Click EDW
3. Click EDW_RecreationOpportunities_01/MapServer
Note the link to the “Legend” for this layer
Read the “Description”
4. Just above the “Description”, click Recreation Areas (0)
Scroll down to the bottom of the page to see the list of attributes the GIS has (or is intended to have) for “Recreation Areas”.
5. See the attribute “RECAREAURL”? This field holds the link that points to the forest service detail page for this recreation feature. When you click on a red recreation feature on the IVM the link that is displayed at the bottom of the popup comes from this data field.

If you would like to know what any of the various attributes in the GIS means, then you need a copy of the ‘data dictionary’ for the GIS. A data dictionary lists each data field and provides a short narrative description of the information stored in that field. Last year I asked for a copy of this document. Since the forest service ignored my polite request, I then re-filed the request as a FOIA. Six months later the FS sent me some B.S. documents that anyone with $.02 worth of knowledge about data management would know are not the GIS data dictionary. I have appealed the decision to refuse to provide me with a copy of the GIS data dictionary to the Chief of the forest service. Note that I was never told the document does not exist. Hey - it’s not like I’m asking for the combo to the vault at Fort Knox. Sheesh!

Finally, if you are really curious, you can use Gmap4 to display any of the data layers from the forest service GIS server as long as the layer is identified as “MapServer”. For “how to” instructions see

For example, here is link that displays the roadless areas.,-117.843262&z=6&t=h,Roadless_ares&rest=

Here is the same link with the &markers parameter added to show a map title and a link to the map legend:,-117.843262&z=6&t=h,Roadless_ares&markers=||title=<b>Roadless%20Areas<br><a%20href=''>Legend</a></b>&rest=

Joseph, the Gmap4 guy
Sorry, only registered users may post in this forum.

Click here to login