Finding and displaying color infrared imagery for the U.S.

I. Finding and downloading (recent) CIR imagery

If you need color infrared (false-color) photos for vegetation analysis, you may find these instructions useful. Many sites (e.g., the USDA Geo Gateway) strip the near-IR band from recent imagery to keep file sizes small. Fortunately, the complete, four-band images are available from the National Map web site. Keep reading to learn how to find and use CIR imagery.

1) Go to http://nationalmap.gov/viewer.html

2) Click on or visit http://viewer.nationalmap.gov/viewer/

3) Zoom in on your area of interest using either the scroll wheel on your mouse or the zoom tool  at the top of the map window
4) Click the Download Data button  You will be asked if you wish to define a download area by drawing a box, by using 1:24k quad sheets, by using the entire visible map, or by entering coordinates. Choose the first option (bounding box). Click and drag over your area of interest (AOI).


5) Next, you are presented with list of available data for your AOI. Choose Orthoimagery and click Next.

6) You will be shown a list of imagery available for your AOI. The first option, 10:1 Compressed NAIP,  contains the 2010-2012 4-band imagery. (Note under “Band” these data are listed as 4B (red, green, blue, and near-infrared)). Check the box next to 10:1Compressed NAIP, then click Next.

7) Your ‘shopping cart’ will appear on the left side of your browser window. Click the Checkout button.

8) Enter your email address twice on the next screen and click Place Order.

9) You should see a confirmation of your order in a pop-up window. Click OK to dismiss the pop-up.

You will receive an e-mail message with links to your download. Note that orthophotos are distributed in 3.75-minute tiles, so each 7.5-minute (1:24,000 scale USGS quagrangle map) will be covered by four photos. A county may require several dozen images for complete coverage.

Four USGS 7.5-minute quads are shown in the image above (Point Nipigon, Cheboygan, Aloha, and Mullett Lake). Sixteen images would need to be downloaded to cover this ~18 x ~12-mile area.

 

II. Displaying Color infrared (CIR) Imagery in ArcGIS

1) After downloading your images, start ArcMap and open a new map document.

2) Use the ArcCatalog tab or the Add Data tool to browse to your data folder. Add the downloaded images to your map. By default, ArcGIS will display the images using a standard, “visible color” scheme (red-green-blue).

3) Right-click on an image and choose Properties… 

4) Choose the Symbology tab and change Red to Band_4, Green to Band_3, and Blue to Band_2. Click Apply, then OK.

5) Your image should change from primarily green to red (assuming you are viewing a forested or otherwise vegetated area).

The top image above is shown in standard (R-G-B) colors; the one below in ‘false color’ NIR-R-G. Healthy, chlorophyll-rich green vegetation is depicted in reds and pinks in false color imagery.

6) Repeat the band settings (changing to bands 4-3-2) for each image in your map.

 

III. Displaying Color Infrared (CIR) Imagery in QGIS

1) After downloading your images, start QGIS and open a new project document (loading a new, empty project document is the default behavior).

2) Use the Browser to view your data folder. If you don’t see the Browser, go to View > Panels and ensure that Browser is checked.

 

3) Next, expand the directory that contains the images you downloaded. Add any images you need by dragging them from the Browser to the map. By default, QGIS will display color imagery  using a standard, “visible color” scheme (red-green-blue).

You could instead use the Add Raster Layer tool (above) to add your images but I find the Browser easier to use.

4) Right-click on an image in your Layers list and choose Properties 

5) Select the Style panel. Set the Red band to display Band 4, the Green to Band 3, and the Blue to Band 2. Click Apply and then OK

6) QGIS will now display your image in shades of red instead of green (assuming you are viewing a forested or otherwise vegetated area).

Note that conifers contain less chlorophyll than deciduous vegetation, so along with differences in texture (conifers often appear coarser), coniferous trees are usually darker on false-color imagery because they reflect less in the NIR band. Coniferous stands are highlighted in the two images above.

Add Coastal Vignettes to your map

Coastal Vignettes are graphic representations of where land and water meet. Vignettes are symbolized so the land appears to gradually fade into the water, representing shallow areas near shore transitioning into deepening water.

Trees

 

 

 

image source: esri

Not wishing to ‘reinvent the wheel’, here are some postings about the creation of coastal vignettes in ArcGIS from the fine cartographers at Esri:

1) Symbolizing Shorelines   2) Ask a cartographer: coastal vignettes  3) FAQ: What are coastal vignettes and how can I create them? 4) Vector and Raster Methods for Creating Coastal Vignettes (ESRI white paper linked from #3).

These were written for older versions of ArcGIS but are still current…

 

 

Student version of ArcGIS (10.1 and 10.2)

ArcGIS 10.2 was recently released. This has changed the method for activating a student edition of ArcGIS 10.1

http://www.esri.com/apps/Products/ArcGIS/ArcEdEval10/index.cfm?event=evaluate.index

Use the link above to pre-register your activation code for ArcGIS 10.1. If you use the link http://www.esri.com/StudentEdition you will see an error (error code 7174) during the activation process.

I should have codes valid for ArcGIS 10.2 in the very near future. Look for further updates here if you are interested.

ArcGIS ModelBuilder tutorial

I have written a short ModelBuilder tutorial that shown how to use an iterator to automate a repetitive process – converting a number of polygon feature classes to rasters in a geodatabase.

If you are interested in learning more about what can be done with the ModelBuilder, explore the ArcGIS Help files (search for ModelBuilder) and work through the two tutorials, or request a code to take the ModelBuilder course from the Virtual Campus.

Introduction to GIS course – first module

I am working on developing a series of self-paced GIS training modules. This first effort is designed for users who have never used ArcGIS before, and is a very simple introduction to using ArcMap.

The data are available to download here.

There is also a link to the data download in the exercise.

More updates and material to follow… You will need access to ArcMap 10.1 and have an Internet connection to complete this module.

Important ArcGIS 10.1 updates

Greetings,

ESRI released Service Pack 1 for ArcGIS 10.1 in late October. This service pack fixes several hundred bugs, and includes other interesting functionality (mainly the release of 64-bit background geoprocessing, allowing for the use of > 4GB of RAM!).

To find current patches and service packs for 10.1, go to http://support.esri.com/ and choose the link Patches and Service Packs under Downloads. Choose ArcGIS for Desktop from the list. Under the Browse Filter, uncheck Version 10 and click Go. Only updates for ArcGIS 10.1 will be listed.

Important patches to apply:

ArcGIS 10.1 Service Pack 1 for (Desktop, Engine, Server)

ArcGIS 10.1 SP1 for Desktop Background Geoprocessing (64-bit) (found under the Product section ArcGIS 10.1 SP1 for Desktop. This product must be installed AFTER SP 1 is installed)

ArcGIS 10.1 SP1 (Desktop, Engine, Server) Mosaic Dataset/Image services reprojection Patch (install after Service Pack 1)

Please note if you have other software installed (ArcGIS for Server or the optional software add-ons Data Reviewer or Workflow Manager) there are separate updaters for these products.

If you are unsure what you have installed, search for PatchFinder for Windows on the SP 1 download page. This software (a tiny ~700 kb download) will report what ESRI products have been installed on your computer.