Thursday, February 11, 2010

Data Layers available for use in ArcMap and ArcGIS Explorer

Below is a collection of links to ArcGIS layer files that point to several different useful web services either hosted by ESRI or by the Tennessee Office of Information Resources, GIS Section. To add layers to ArcMap or to ArcGIS Explorer, simply download the layer files and open them as you would any other GIS data layer (double-clicking them will probably work as well).

If you don't have ArcGIS installed and you're working with a Windows system, you can get ArcGISExplorer, a free viewer here. You can also visit the TDEC web mapping site here, if you simply wish to view TDEC's available gis data over the web.

ESRI Layers (click here to visit site and download layer files):

  • Worldwide Imagery
  • National Geographic/USGS Topographic Maps
  • Weather Radar
  • DeLorme Maps
  • Worldwide Street Maps
  • and more . . .

Data Hosted by the Tennessee Office of Information Resources GIS Section (TNmap):

Thursday, September 10, 2009

Very Large List of Useful GIS Data Sources

The PDF from an ESRI educational class has many links to GIS data sources and viewer utilities.

To access the PDF, just download the zip archive. It looks like you're downloading some sort of official ESRI course, but it's just a one-file pdf document that explains how to access a ton of free GIS data:

Friday, November 21, 2008

Converting Geodatabases to Shapefiles and Reprojecting Data in ArcGIS

  1. Open an empty Arcmap and open the Geodatabase containing the layers you wish to convert/reproject.
  2. Go to the View Menu and choose Data Frame Properties . . .
  3. In the Data Frame Properties Dialog Box choose the Coordinate System tab. The current coordinate system that appears should be the same as that of the Geodatabase (likely Tennessee State Plane if you're using TDEC data). We're going to change the coordinate system for the data frame to whatever the new coordinate system you want to use for your exported data.
  4. Change the coordinate system for the data frame. If you're converting from TN State Plane to Decimal Degrees, choose the following in the "Select a Coordinate System" box: Expand "Predefined", Expand "Geographic Coordinate Systems", Expand "North America", Select "North American Datum 1983". Click Apply and OK, and then Yes to the warning dialogs if they appear. (The warnings shouldn't apply to the data we use unless you've got something in the older North American Datum 1927. A lot of decimal degrees data is in the WGS 1984 datum which is just a worldwide expansion of NAD 1983.)
  5. To Export as a shapefile in decimal degrees, you simply left-click on each feature layer in the geodatabase and choose Export . . . Make sure that you click the "Use the same coordinate system as: the data frame" radio button--this will apply the coordinate system you just set to the shapefiles you output:

You're done! If necessary you may with to go into your View-->Data Frame Properties and change your coordinate system settings back to the original coordinate system. For Tennessee State Plane (TDEC's standard), you'd choose Predefined-->Projected Coordinate Systems-->State Plane-->NAD 1983(Feet)-->NAD 1983 StatePlane Tennessee FIPS 4100 (Feet).

Wednesday, October 8, 2008

HUC 8/12 Shapefiles

NRCS is in process of creating a hydrologically correct, seamless and consistent national GIS database at a scale of 1:24,000, which has been extensively reviewed. The HUC 12 dataset for Tennessee is now finished and it has been downloaded. Our new shapefiles include, in their entirety, watersheds that we share with other states.

We now have a HUC 12 Shapefile for our use at- S:\Water\HUC12_TN_Sept2008.shp

Those HUC 12 boundaries were then merged together to give us a new HUC 8 shapefile and it is located at- S:\Water\HUC8_from_HUC12_TN_Sept2008.shp

If you have any questions - please feel free to give me a call
-Regan Mcgahen

Tuesday, October 7, 2008

One Click for Aerial Photos, Streets, Topos in ArcMap

I just helped someone in one of the field offices set up a map document in ArcMap and we discovered that ESRI's Web Service data, including National Geographic Topos, Streets, and Aerial Photos (better coverage than Google Maps/Earth) are now available for ArcMap without creating an ESRI user account.

Try opening this Map Document and using it as a basemap!

Monday, September 8, 2008

High Quality Streams

Michael Graf of Water Pollution Control has created a new High Quality Streams shapefile for TDEC use. There are two shapefiles one for linear streams and one for polygon waterbodies. These data were created using 1:24,000 NHD has the source.

Taken from the Metadata:

Tennessee’s water quality standards require the incorporation of the antidegradation policy into regulatory decisions (Chapter 1200-4-3-.06). Part of the responsibility the policy places on the Division of Water Pollution Control is identification of exceptional Tennessee Waters (previously know as Tier 2) and Outstanding National Resource Waters (Tier 3). In exceptional waters, degradation cannot be authorized unless (1) there is no reasonable alternative to the proposed activity that would render it non-degrading and (2) the activity is in the economic or social interest of the public. In Outstanding National Resource Waters, no new discharges, expansions of existing discharges, or mixing zones will be permitted unless such activity will not result in measurable degradation of the water quality.
The Division of Water Pollution Control has compiled the list of waters based on the characteristics of Exceptional Tennessee Waters and Outstanding National Resource Waters set forth in the regulation by the Tennessee Water Quality Control Board. In general, these are waterbodies with good water quality, important ecological values, valuable recreational uses, and outstanding scenery. Wherever possible, the Division has utilized objective measures to apply these characteristics and the basis for each listing is provided.

This is a draft version of the High Quality Streams Map for Tennessee. The data set is currently being developed and reviewed by the Tennessee Department of Environment and Conservation - Division of Water Pollution Control. The draft map is incomplete at this time and is only intended to be used as a mapping tool to help locate these high quality waters. Original data was taken from the WaterLog, which is maitained by the Division of Water Pollution Control. The WaterLog is the most autoritative and current place to view a listing of the High Quality Streams (a.k.a. Exceptional Tennessee Waters). The most recently published list of these waters available to the public can be found at

If there are any questions, feel free to contact me (Rich Cochran) or Michael Graf.

Friday, June 27, 2008

Open Layers Map

Open Layers provides a web-based Javascript front-end for mapping. There are no licensing restrictions and it can easily connect to a variety of web services including USGS Topos/Aerial Photos, Microsoft Virtual Earth, and Google Maps. You just paste your javascript code in any webpage and you've got a nice web map.

Here's an example (after loading the page, click on the right side + to view USGS topos):

Friday, May 2, 2008

updating your coordinates on the fly

Have you ever needed to correct the coordinate or location of a point in your dataset?
A couple of useful scripts, found on the ESRI page, allows you to do this, on the fly.
No need to add additional fields, or rebuild your shapefile from a recently updated table.

One of these tools allows you to correct the coordinate in your attribute data and then it updates the location of your point based on the new attribute data.

Another tool allows you to move your point to the correct location and then update the attributes based on the new location.

Let me know if you are interested in learning more about these tools.

Saturday, April 5, 2008

Next TDEC GIS users Meeting

May 8th 10:00
Place TBA

TNGIC notes

I just wanted to take the time to write some quick notes about TNGIC...

A variety of sessions took place on March 26-27, including local, state, federal, and academic.
TNGIC is always a great place to see what others are doing with GIS around the state, and one can't help but to compare it to where we (TDEC) are. Some agencies are faced with the same issues... lack of resources primarily. So we are not alone! However, it does get somewhat mind boggling when talking with those who are out there on the cutting edge of GIS and doing some phenomenal things!

Some topics of interest were: Customized Stormwater Permitting Applications (Hamilton County), Reservoir Modeling (USFW), The Cumberland Trail (TDEC), Using GIS as a Weapon in the War on Meth TN Meth Task Force), Obtaining your GISP, ArcGIS Tips and Tricks, Integrating Modern and Historic Maps at Pinson Mounds, and more.

It is always a good thing to her from the ESRI folks about what is coming up in the months o come (at least it allows me to dream for awhile).

Lee Wetherington (Goldleaf Technologies) and Learon Dalby (Arkansas GIS), the key note speakers, were good.

The best part of TNGIC is the chance to get to see so many people from different areas of the state who are working in the world of GIS on a daily basis.

I encourage you to put it on your calender for next year!

Thursday, February 14, 2008

Google Earth Licensing Less Restrictive

Last fall, Google updated the software license for the free version of Google Earth. The license now permits business entities (including state/local governments) to use the software for internal purposes.

The license can be found here.

DNR Garmin (Free GPS software) Update Available

Bill Avant sent this around:

DNRGarmin 5.3.2 is now available on the Minnesota DNR's website at
Bug fixes include:
  • USB Connectivity now works for users without ADMIN rights to their computers.

  • Automation Error (#-2147467259) when saving to a File Geodatabase -- Fixed.

  • RLIDENT field will now save up to 15 characters (previous limit of 10)


Friday, January 25, 2008

More GIS Links

If you're curious about scripting in ArcGIS, here are some relevant links:

Wednesday, January 23, 2008

Public Lands shapefiles

From the 2007 Rec Atlas project, the public lands layers are on TDEC's GIS server. I have broken them out as individual shapefiles and provided a little metadata.

Friday, January 18, 2008

How to Use Parcel and Other Data from OIRs Webmapping Service

The TN Office of Information Resources (OIR) maintains the Tennessee One Map which makes available several datasets created by the Tennessee Basemapping Program.

Data hosted by OIR includes:

2006 100' and 400' Black and White Aerial Photography (Leaf Off)
2006 National Ag Imagery Program Aerial Photography (Leaf-On)
1:24000 Streams
Parcels by County

For detailed information on how to connect ArcGIS ArcView software to the TN One Map data, click here:


Friday, December 7, 2007

Ecoregion Delineation Changes

It was discovered yesterday by staff that EPA updated the Ecoregion delineations for Tennessee. According to EPA, they did the work back in 2001 and again in 2003 but failed to notify anyone at TDEC of the changes. Thanks to Courtney Brame for noticing the changes.

Anyway, it appears we now have 6 new ecoregion delineations.

73b Northern Pleistocene Valley Trains --- split out of a portion of 73a Mississippi Alluvial Plains
69c Cumberland Mountain Thrust Block --- split out of 69d Dissected Appalachian Plateau; also changed this name in the old data 69d was called Cumberland Mountains

66j Broad Basins --- split out of 66g Southern Metasedimentary Mountains; This new area is in the Copper Basin area of the state
66i High Mountains --- split out of 66g Southern Metasedimentary Mountains; These new areas are along the NC border

66k Amphibolite Mountains --- Split from 66d Southern Crystaline Ridges and Mountains; This new area is very small and located on the NC border in Johnson County, TN

68d Southern Table Plateaus --- In the old data set this was a very small blob on the southern border of TN and Alabama/Georgia that was considered 68a Cumberland Plateau

Also, it appears that they re delineated 71h Outer Nashville Basin so that it now connects with KY.

The image shows the new delineations highlighted in red.

Thursday, December 6, 2007

What data is currently available on S and T?

What do we have on the TDEC GIS Server (the S and T drives) as of December 6, 2007?

First, a good way to understand the difference between S: and T: is to know that 'S' is short for statewide data. The S: drive is a repository for basemap data like aerial photos, roads, streams, USGS topos, national elevation data, county and city boundaries, and so forth.

The T: drive, with 'T' being short for 'TDEC', is the place where different Divisions can store and share data that have been generated in-house. So the T: drive might have impaired streams published by Water Pollution Control, trails and park boundaries published by Parks, and so-on. To get data posted on T: you should create metadata and then put files in the 'New Data' folder. Let Gayle know you put the data there and she'll work with you to get it posted in a more suitable location on T:.

Always, check the metadata to ensure data you decide to use is suitable for your task. Some data may be old and need updating.

With the overall difference between S: and T: in mind, here's a quick rundown of the main data layers on S: (Look for a T: Drive layer listing in the future as the Divisons add more data.)


Admin contains boundaries like counties, states, political districts, Field Office boundaries, Natural Area and State Park boundaries, and pipelines and powerlines.


Aerial Photos 406:

NAIP_2004: 2004 COLOR Aerial Photos for 21 TN counties from the USDA National Ag Inventory Program, 1-2 meter resolution, UTM NAD83

NAIP_2006: 2006 COLOR Aerial Photos for MOST TN counties from the USDA National Ag Inventory Program, 1 FOOT resolution, UTM NAD83

HSUC_2005: 2005 Hi-Res Black and White and Color Aerial Photos for Upper Cumberland Plateau Counties, TN State Plane

DOQ_DD_1997-1999: Black and White Aerial Photos, USGS?, Statewide, Decimal Degrees

COUNTY_UTM_1997-1999: 1 Meter Black and White Aerial Photos from NRCS, Statewide, UTM NAD83

Upper Cumberland: 2005 Color and Black and White Aerial Photos for the Upper Cumberland Region


caves: limited coverage of caves in TN, DD

physprov: TN physiographic provinces, DD

sp nat pub 0708: TN natural areas and state parks with public access as of 07/08, TN State Plane

Ecoregions: USEPA Ecoregions for Tennessee and surrounding states, DD

lulc_25: 1997 land use land cover imagery for Tennessee from TWRA, 25 meter pixel resolution, TN State Plane

lulc_100: 1997 land use land cover imagery for Tennessee from TWRA, 100 meter pixel resolution, TN State Plane

mrlc_2001: 2001 land use land cover imagery for Tennesee from USGS, 30 meter pixel resolution, TN State Plane

NED: USGS National Elevational Dataset digital elevation models by USGS 8-digit HUC (watershed), 30 meter pixel resolution, TN State Plane

NRCS Soils: Low Resolution Statsgo Soils for Tennessee, Statewide, TN State Plane

TeleAtlas Month-Year (currently 0707):

Statewide: Statewide layers for airports, bus stations, cemeteries, census boundaries, city boundaries, county boundaries, highways, hwy signs, institutions, interstate exits, landmarks, malls, parks, population, railroads, rec areas, streets, waterbodies, zipcodes, TN State Plane

County: Same as above by county.

TN Base Mapping Products:

2004?, 2005? Data for most TN counties (TN State Plane) including: 1 meter black and white aerial photos, Parcels, Soils, roads from TDOT, administrative boundaries, hydrography, political districts, tree cover

Topographic Maps: 1:24000, 1:100000, 1:250000 Scale USGS Topographic Maps (digital raster graphics), by quadrangle, TN State Plane

NOTE: for statewide use, an image catalog is available that will let you load whatever quadrangles are in your viewframe--contact me if you need the file.

Water (for help contact Rich Cochran):

NHD: National Hydrography Dataset, 1:100,000 Scale Streams and Lakes with hydrologic connectivity, DD (special extensions may be needed for full functionality)

NHD HighRes: National Hydrography Dataset, 1:24,000 Scale Streams and Lakes with hydrologic connectivity, DD (special extensions may be needed for full functionality)

Major Rivers: 1:250,000 Scale, DD

Major Lakes: 1:250,000 Scale, DD

Reach 1: 1:250,000 Scale Streams from EPA, DD

tn annual precip line: 1998 lines showing avg. annual rainfall, DD, Univ. of Oregon, PRISM data

tn annual precip poly: 1998 polygons showing avg. annual rainfall, DD, Univ. of Oregon, PRISM data

TN_HUC8_boundaries: Watersheds by USGS 8 digit huc code, DD

TN_HUC12_boundaries: Watersheds by USGS 12 digit huc code, DD

tn_huc_12: probably same as above

HUC8: probably same as above

NWI: National Wetlands Inventory Data for US Fish and Wildlife Service, preliminary indicator of wetlands by quadrangle, 1970s-early 1990s, DD (contact me for a statewide ArcView 3.x tool to display all quads in view)

There are probably some errors in my descriptions, but my hope is that this is helpful in determining what data is available. Please post/respond if you notice inaccuracies.


Monday, December 3, 2007

Impervious Cover

I just put a new shapefile up on the server that models Impervious Cover in Tennessee. The data was produced by EPA Region 4. Essentially they determined the percent impervious cover for each HUC 12 subwatershed. This was done for the year 2000 and then modeled using growth estimates for 2010 and 2020.

It can be categorized by the pcttia2000, pcttia2010, or pcttia2020 to show the percentages. In the EPA report for the data they tended to show the data as 5 categories: <> 20%. The online report address is included in the metadata file.

If folks have trouble they can give me a call and I'll try to help out.


Friday, November 16, 2007

Streams Impaired By Siltation

I just placed two new data files on the server: 2006statewidesiltation and 2006statewidesiltation_wb. These shapefiles represent streams and waterbodies impaired by siltation as listed in the 2006 303(d) list of impaired streams.

Used the Cause_Id field to classify this data. You'll get streams grouped as 371 (the code for siltation) and 0 (everything else). So those streams impaired by siltation will draw with the 371 code.

The files will be placed on the T drive in the Water folder.

Monday, November 5, 2007

GIS DAY 2007

Come and celebrate GIS DAY 2007 on November 19 at the L & C Towers, 17th Floor, from 9 AM to 3 PM. There will be GIS presentation from 11 AM to 1 PM, GIS demonstrations given by TDEC GIS Users, Map Displays, and Door Prizes (must be present to win)! Hope to you all there!!