{"id":947,"date":"2014-07-16T17:26:33","date_gmt":"2014-07-16T21:26:33","guid":{"rendered":"http:\/\/www.gis.mtu.edu\/?p=947"},"modified":"2015-03-30T13:00:33","modified_gmt":"2015-03-30T17:00:33","slug":"finding-and-displaying-color-infrared-imagery-for-the-us","status":"publish","type":"post","link":"https:\/\/www.gis.mtu.edu\/?p=947","title":{"rendered":"Finding and displaying color infrared imagery for the U.S."},"content":{"rendered":"

I. Finding and downloading (recent) CIR imagery<\/strong><\/p>\n

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. <\/p>\n

1) Go to http:\/\/nationalmap.gov\/viewer.html<\/a><\/p>\n

2) Click on \"\"<\/a>or visit http:\/\/viewer.nationalmap.gov\/viewer\/<\/a><\/p>\n

3) Zoom in on your area of interest using either the scroll wheel on your mouse or the zoom tool\u00a0\"\"<\/a> at the top of the map window
\n4) Click the Download Data<\/strong> button\u00a0\"\"<\/a> 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<\/strong>). Click and drag over your area of interest (AOI).<\/p>\n

\"\"<\/a>
\n5) Next, you are presented with list of available data for your AOI. Choose Orthoimagery<\/strong> and click Next<\/strong>.<\/p>\n

\"\"<\/a><\/p>\n

6) You will be shown a list of imagery available for your AOI. The first option, 10:1 Compressed NAIP<\/strong>,\u00a0 contains the 2010-2012 4-band imagery. (Note under \u201cBand\u201d these data are listed as 4B (red, green, blue, and near-infrared)). Check the box next to 10:1Compressed NAIP<\/strong>, then click Next<\/strong>.<\/p>\n

\"\"<\/a><\/p>\n

7) Your \u2018shopping cart\u2019 will appear on the left side of your browser window. Click the Checkout<\/strong> button.<\/p>\n

\"\"<\/a><\/p>\n

8) Enter your email address twice on the next screen and click Place Order<\/strong>.<\/p>\n

\"\"<\/a><\/p>\n

9) You should see a confirmation of your order in a pop-up window. Click OK<\/strong> to dismiss the pop-up.<\/p>\n

\"\"<\/a><\/p>\n

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.<\/p>\n

\"\"<\/a><\/p>\n

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.<\/p>\n

 <\/p>\n

II. Displaying Color infrared (CIR) Imagery in ArcGIS<\/strong><\/p>\n

1) After downloading your images, start ArcMap and open a new map document.<\/p>\n

2) Use the ArcCatalog<\/strong> tab or the Add Data<\/strong> tool to browse to your data folder. Add the downloaded images to your map. By default, ArcGIS will display the images using a standard, \u201cvisible color\u201d scheme (red-green-blue).<\/p>\n

3) Right-click on an image and choose Properties…<\/strong>\u00a0\"\"<\/a><\/p>\n

4) Choose the Symbology<\/strong> tab and change Red<\/strong> to Band_4<\/strong>, Green<\/strong> to Band_1<\/strong>, and Blue<\/strong> to Band_2<\/strong>. Click Apply<\/strong>, then OK<\/strong>.<\/p>\n

\"\"<\/a><\/p>\n

5) Your image should change from primarily green to red (assuming you are viewing a forested or otherwise vegetated area).<\/p>\n

\"\"<\/a>\"\"<\/a><\/p>\n

The top image above is shown in standard (R-G-B) colors; the one below in \u2018false color\u2019 NIR-R-G. Healthy, chlorophyll-rich green vegetation is depicted in reds and pinks in false color imagery. Note that Sherman Field, Michigan Tech’s football field, is artificial turf: it appears green to the naked eye (standard color image), but is nearly black on the CIR image. Infrared film was originally known as ‘camouflage detection film’ due to the ability to resolve ‘fake’ vegetation in this manner. <\/p>\n

6) Repeat the band settings (changing to bands 4-1-2) for each image in your map.<\/p>\n

 <\/p>\n

III. Displaying Color Infrared (CIR) Imagery in QGIS<\/strong><\/p>\n

1) After downloading your images, start QGIS and open a new project document (loading a new, empty project document is the default behavior).<\/p>\n

2) Use the Browser<\/strong> to view your data folder. If you don\u2019t see the Browser, go to View > Panels<\/strong> and ensure that Browser<\/strong> is checked.\"\"<\/a><\/p>\n

 <\/p>\n

3) Next, expand the directory that contains the images you downloaded. Add any images you need by dragging them from the Browser<\/strong> to the map<\/strong>. By default, QGIS will display color imagery\u00a0 using a standard, \u201cvisible color\u201d scheme (red-green-blue).<\/p>\n

\"\"<\/a><\/p>\n

You could instead use the Add Raster Layer<\/strong> tool (above) to add your images but I find the Browser<\/strong> easier to use.<\/p>\n

4) Right-click<\/strong> on an image in your Layers<\/strong> list and choose Properties\u00a0\"\"<\/a><\/strong><\/p>\n

5) Select the Style<\/strong> panel. Set the Red<\/strong> band to display Band 4<\/strong>, the Green<\/strong> to Band 1<\/strong>, and the Blue<\/strong> to Band 2<\/strong>. Click Apply<\/strong> and then OK<\/strong>.\"\"<\/a><\/p>\n

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

\"\"<\/a>\"\"<\/a><\/p>\n

Note that conifers have different leaf cell structure and contain less chlorophyll than deciduous vegetation, so along with differences in texture<\/em> (conifers often appear coarser), coniferous trees are usually darker<\/em> on false-color imagery because they reflect less energy in the NIR band. A coniferous stand is highlighted in the two images above.<\/p>\n","protected":false},"excerpt":{"rendered":"

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 … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,4],"tags":[46,64,38,104,66],"class_list":["post-947","post","type-post","status-publish","format-standard","hentry","category-how-to","category-information","tag-arcmap","tag-how-to-2","tag-howto","tag-qgis","tag-tutorial"],"_links":{"self":[{"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/posts\/947","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=947"}],"version-history":[{"count":21,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/posts\/947\/revisions"}],"predecessor-version":[{"id":974,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=\/wp\/v2\/posts\/947\/revisions\/974"}],"wp:attachment":[{"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=947"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=947"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gis.mtu.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=947"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}