{"id":384,"date":"2026-09-30T09:51:43","date_gmt":"2026-09-30T09:51:43","guid":{"rendered":"https:\/\/helpwithmygisassignment.com\/blog\/?p=384"},"modified":"2026-09-30T09:51:43","modified_gmt":"2026-09-30T09:51:43","slug":"how-to-calculate-ndvi-in-qgis","status":"publish","type":"post","link":"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/","title":{"rendered":"How to Calculate NDVI in QGIS: 10 Easy Steps"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_89 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#How_to_Calculate_NDVI_in_QGIS_A_Step-by-Step_Guide_for_Students\" >How to Calculate NDVI in QGIS: A Step-by-Step Guide for Students<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#1_What_Does_NDVI_Measure\" >1. What Does NDVI Measure?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Why_do_the_bands_matter\" >Why do the bands matter?<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#2_Which_Bands_Should_You_Use\" >2. Which Bands Should You Use?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Landsat_89\" >Landsat 8\/9<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Sentinel-2\" >Sentinel-2<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#3_Prepare_Your_Satellite_Imagery\" >3. Prepare Your Satellite Imagery<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Check_the_layers\" >Check the layers<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#4_How_to_Calculate_NDVI_in_QGIS_Using_the_Raster_Calculator\" >4. How to Calculate NDVI in QGIS Using the Raster Calculator<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Step_1_Select_the_NIR_band\" >Step 1: Select the NIR band<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Step_2_Select_the_Red_band\" >Step 2: Select the Red band<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Step_3_Enter_the_NDVI_formula\" >Step 3: Enter the NDVI formula<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#5_Set_the_Output_Raster\" >5. Set the Output Raster<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#6_Apply_a_Color_Ramp_From_-1_to_1\" >6. Apply a Color Ramp From -1 to +1<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#7_How_to_Interpret_Your_NDVI_Map\" >7. How to Interpret Your NDVI Map<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#-1_to_0_Water_and_non-vegetated_surfaces\" >-1 to 0: Water and non-vegetated surfaces<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#0_to_02_Bare_or_sparsely_vegetated_surfaces\" >0 to 0.2: Bare or sparsely vegetated surfaces<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#02_to_08_Vegetation\" >0.2 to 0.8: Vegetation<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#8_Troubleshooting_Common_NDVI_Problems\" >8. Troubleshooting Common NDVI Problems<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Problem_1_Your_NDVI_values_look_like_integers\" >Problem 1: Your NDVI values look like integers<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Solution\" >Solution<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Problem_2_Strange_values_caused_by_division_by_zero\" >Problem 2: Strange values caused by division by zero<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Solution-2\" >Solution<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#9_Other_Reasons_Your_NDVI_Map_May_Look_Wrong\" >9. Other Reasons Your NDVI Map May Look Wrong<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-25\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Check_your_band_selection\" >Check your band selection<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-26\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Check_that_the_bands_come_from_the_same_scene\" >Check that the bands come from the same scene<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-27\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Check_spatial_alignment\" >Check spatial alignment<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-28\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Check_preprocessing\" >Check preprocessing<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-29\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#10_Complete_NDVI_Workflow_at_a_Glance\" >10. Complete NDVI Workflow at a Glance<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-30\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Quick_Reference\" >Quick Reference<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-31\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/#Final_Takeaway\" >Final Takeaway<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1><span class=\"ez-toc-section\" id=\"How_to_Calculate_NDVI_in_QGIS_A_Step-by-Step_Guide_for_Students\"><\/span>How to Calculate NDVI in QGIS: A Step-by-Step Guide for Students<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>If you are learning <strong>how to calculate NDVI in QGIS<\/strong>, you are working with one of the most widely used vegetation indices in remote sensing. The Normalized Difference Vegetation Index (NDVI) uses the relationship between <strong>Near Infrared (NIR)<\/strong> and <strong>Red<\/strong> wavelengths to estimate the presence and relative vigor of green vegetation. It is useful for vegetation health analysis, agricultural monitoring, land-cover studies, and environmental <a href=\"https:\/\/helpwithmygisassignment.com\/\">GIS projects.<\/a><\/p>\n<p>The basic NDVI equation is:<\/p>\n<p><span class=\"katex\">NDVI=NIR\u2212RedNIR+RedNDVI = \\frac{NIR &#8211; Red}{NIR + Red}<\/span><\/p>\n<p>The result normally ranges from <strong>-1 to +1<\/strong>. Correctly identifying the NIR and Red bands is critical because using the wrong bands will produce an incorrect vegetation map.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"1_What_Does_NDVI_Measure\"><\/span>1. What Does NDVI Measure?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Healthy green vegetation strongly absorbs <strong>red light<\/strong> for photosynthesis while reflecting relatively large amounts of <strong>Near Infrared (NIR)<\/strong> radiation.<\/p>\n<p>NDVI takes advantage of this difference:<\/p>\n<ul>\n<li><strong>Healthy vegetation \u2192 high NIR reflection + low Red reflection \u2192 higher NDVI<\/strong><\/li>\n<li><strong>Bare soil or sparse vegetation \u2192 smaller difference \u2192 lower NDVI<\/strong><\/li>\n<li><strong>Water \u2192 very low or negative NDVI<\/strong><\/li>\n<\/ul>\n<p>This makes NDVI useful for quickly examining vegetation patterns across a satellite image.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Why_do_the_bands_matter\"><\/span>Why do the bands matter?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>NDVI specifically requires:<\/p>\n<ol>\n<li>A <strong>Near Infrared (NIR)<\/strong> band<\/li>\n<li>A <strong>Red<\/strong> band<\/li>\n<\/ol>\n<p>Different satellite missions assign different band numbers to these wavelengths. Therefore, you cannot simply use &#8220;Band 4&#8221; and &#8220;Band 5&#8221; without checking which satellite produced the imagery.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"2_Which_Bands_Should_You_Use\"><\/span>2. Which Bands Should You Use?<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>Before opening the Raster Calculator, identify the correct bands for your satellite imagery.<\/p>\n<table>\n<thead>\n<tr>\n<th>Satellite<\/th>\n<th>Red Band<\/th>\n<th>NIR Band<\/th>\n<th>NDVI Formula<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Landsat 8<\/strong><\/td>\n<td>B4<\/td>\n<td>B5<\/td>\n<td><code>(B5 - B4) \/ (B5 + B4)<\/code><\/td>\n<\/tr>\n<tr>\n<td><strong>Landsat 9<\/strong><\/td>\n<td>B4<\/td>\n<td>B5<\/td>\n<td><code>(B5 - B4) \/ (B5 + B4)<\/code><\/td>\n<\/tr>\n<tr>\n<td><strong>Sentinel-2<\/strong><\/td>\n<td>B4<\/td>\n<td>B8<\/td>\n<td><code>(B8 - B4) \/ (B8 + B4)<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><span class=\"ez-toc-section\" id=\"Landsat_89\"><\/span>Landsat 8\/9<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>For Landsat 8 and Landsat 9:<\/p>\n<ul>\n<li><strong>B4 = Red<\/strong><\/li>\n<li><strong>B5 = Near Infrared<\/strong><\/li>\n<\/ul>\n<p>Therefore:<\/p>\n<p><span class=\"katex\">NDVI=B5\u2212B4B5+B4NDVI = \\frac{B5-B4}{B5+B4}<\/span><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Sentinel-2\"><\/span>Sentinel-2<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>For Sentinel-2:<\/p>\n<ul>\n<li><strong>B4 = Red<\/strong><\/li>\n<li><strong>B8 = Near Infrared<\/strong><\/li>\n<\/ul>\n<p>Therefore:<\/p>\n<p><span class=\"katex\">NDVI=B8\u2212B4B8+B4NDVI = \\frac{B8-B4}{B8+B4}<\/span><\/p>\n<p><strong>Important:<\/strong> Sentinel-2 also contains B8A, another NIR-related band. For a basic Sentinel-2 NDVI workflow, use <strong>B8 and B4<\/strong> consistently.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"3_Prepare_Your_Satellite_Imagery\"><\/span>3. Prepare Your Satellite Imagery<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>You need the Red and NIR raster layers before calculating NDVI.<\/p>\n<p>For example, if you are working with Landsat 8, your project might contain:<\/p>\n<pre><code class=\"language-text\">B4.tif\r\nB5.tif<\/code><\/pre>\n<p>For Sentinel-2:<\/p>\n<pre><code class=\"language-text\">B4.tif\r\nB8.tif<\/code><\/pre>\n<p>You can load them into <a href=\"https:\/\/www.qgis.org\" target=\"_blank\" rel=\"noopener\">QGIS<\/a> using:<\/p>\n<p><strong>Layer \u2192 Add Layer \u2192 Add Raster Layer<\/strong><\/p>\n<p>Select the required bands and click <strong>Add<\/strong>.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/TygRPeU0dL3NzgDjYLcAmR6g50NJdLkB0Qd1KPRJKmd02FUbm9Y7Xj5eteB3uu4yBX1VPO0SdOmsmqeV3ZS7603jfffx0e9llX5pUdjxkOCGLFaK9_gnWwGwHwL3525umZLjCuuUdkFTQWKhJK78JLm9qK2OGPlhunCAWQFVooxpbnjzYIVOAkrHw5RZyZQK?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/2jHivoa1B6EvB0fUNjQOvLLoReu8TMWqAh3xmjRAloeyUUBOAzCT5Ai6JKXdbHpO7G-enXUxWsm8eXw_YNWt2Hd0V-jO8kgfB-IeK_m79oHXTqlf0o6uVddzrCXsnr69wDCvZmFvnNV0HlJqZFb2ttVS629An6EWTKfdgMwxZzvkgBvUtkskxEQShWjvSDIJ?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/ih8RScnH5tEDgtdlTpbOApVuw3MPINst97_k2DHbaYh_t0is_HQWj8_V4YGVF_-2j4khpxG5WNitqwJ36z4iD7wPoFQTOD8YdHOYeHbi99cF_FolA2CfS21QSopc2gr_XtI_ijXAIhujrfq9ffVRTOrq0FxQFkimNDxWYQlG4Km0qIUkMJ8NIi53NYcnjaON?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/5vqrJov5L8MjEZy7iacfN_A6PKMb7L83e7jNXfMKExa3DZj-4qmsJCjaOL_nQeg8meVCfY9C0Oczuloz2seAdETQF4kRQGqv8I9n41FmeGKQLOkeiOrBeti7_t-mmiE3Pe5_7cJBRxcYjGQ1FYkZpR6ycH9ilYieDPWpV5yIZMxqVFebHbJPJT5oISKJDjnf?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Check_the_layers\"><\/span>Check the layers<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Before calculating NDVI, make sure:<\/p>\n<ul>\n<li>Both bands cover the same study area.<\/li>\n<li>They have compatible pixel sizes.<\/li>\n<li>They use the appropriate coordinate reference system.<\/li>\n<li>They are from the same image acquisition date.<\/li>\n<li>You are using surface-reflectance or otherwise appropriately processed imagery for your analysis.<\/li>\n<\/ul>\n<p>Using bands from different dates can produce misleading NDVI patterns because vegetation and atmospheric conditions may have changed.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"4_How_to_Calculate_NDVI_in_QGIS_Using_the_Raster_Calculator\"><\/span>4. How to Calculate NDVI in QGIS Using the Raster Calculator<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>The <strong>QGIS Raster Calculator<\/strong> performs mathematical operations on raster pixels.<\/p>\n<p>Open it from:<\/p>\n<p><strong>Raster \u2192 Raster Calculator<\/strong><\/p>\n<p>Depending on your QGIS version, you may also find it through the Processing Toolbox by searching for <strong>Raster Calculator<\/strong>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/images.openai.com\/static-rsc-4\/d1OUEcSbFaVDW9Y2YVMAtNxVXHERiCXWSTUVKSPHpnJ7dg2KqiyKvgQtkCGRmAGac48vhVsOAYTOGg1DPLzIO8neEeyFKHHRwE47mawqaF_9FYMalLv0YIifGPJdMPTiBptzihpivkbfSehKVarJgNNzQjutMWk9O6pOQnbygihGz0kZeWVyf2qeoTGrPv18?purpose=fullsize\" alt=\"IHow to calculate NDVI in QGIS workflow\" width=\"2048\" height=\"1535\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/QMYxKORghMDC69XSd-vFToiAzccRAAJo1QEiHntHzwwOoZCEfWzv5TXbzEVhtecK-yLm3gsaqK0kOFZRf5gq3XLlVxscvjnPMgqulCZu8rbZipSHUoawkTb8EFARP7C_gkbZxvSiCZOswOE-OzgI_Rp1v_62P7-6X8Zx9HbViAxNdnPSiVr9wHz3c-iFIPJ7?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/yB_r9ocNIUYXteFa0bKmbOaBL5St7NOJMm_LN6OgwBVz6BE4UPC91hwW4T-oaIRKafUNl9w0NPy4P9hKFBYR6HGZFzObf7IO1i4PHaQMJH8o-0Yw9t6Diri23iMlc5wI-V-HUHz6O5cyxon8BszV0NXXAyMTjUzrZphFEJy4OIUvEW6FnmkTKmqY7nAEjC6g?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/uT0XHLo0_PqYtATDq5z4hcgWCWeZyEv3B96CXNvy573C2zIgoci5ur-869rXrO4gE6mZDP7kMeBzPBaQSxUhiE2w7HHG4ia33qKJG5uPdvDya7c3KCp62PHkwnLcTD7yKidmr3g08Z58-FCci7SyVJHYVGXzSmBxst-1JWcnUMVbCm2_C8J_h29erdr4oVp5?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/X8j_z2CzG0dS5cSMLI7u365EKiqRfgW5UirH-KjS2uhEAV4lTbh1y3hBKuhXgnCQnMPyc0Ja03QPwNz8iL3Nqp0frX4cp3bMBbhzPvBPse4pbmLBb2FQuxJ1R6bIPeAsqMUSlGBe51lXZGsxDCwBwWcyww3I3qpljXbaVyMiuO1e8whrRhYU4jDXF9tFTZC1?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Step_1_Select_the_NIR_band\"><\/span>Step 1: Select the NIR band<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Suppose your Landsat layers are named:<\/p>\n<pre><code class=\"language-text\">B5\r\nB4<\/code><\/pre>\n<p>B5 is your NIR band.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Step_2_Select_the_Red_band\"><\/span>Step 2: Select the Red band<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>B4 is your Red band.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Step_3_Enter_the_NDVI_formula\"><\/span>Step 3: Enter the NDVI formula<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The fundamental syntax is:<\/p>\n<pre><code class=\"language-text\">(NIR - Red) \/ (NIR + Red)<\/code><\/pre>\n<p>For Landsat 8\/9, this becomes:<\/p>\n<pre><code class=\"language-text\">(\"B5@1\" - \"B4@1\") \/ (\"B5@1\" + \"B4@1\")<\/code><\/pre>\n<p>For Sentinel-2:<\/p>\n<pre><code class=\"language-text\">(\"B8@1\" - \"B4@1\") \/ (\"B8@1\" + \"B4@1\")<\/code><\/pre>\n<p>The exact layer names displayed in your Raster Calculator may differ. <strong>Use the names shown in your QGIS raster-band list rather than blindly copying the examples.<\/strong><\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"5_Set_the_Output_Raster\"><\/span>5. Set the Output Raster<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>After entering your formula, configure the output.<\/p>\n<p>Choose an output file such as:<\/p>\n<pre><code class=\"language-text\">NDVI.tif<\/code><\/pre>\n<p>For the output extent and resolution, it is generally appropriate to match the input raster you are using.<\/p>\n<p>For example:<\/p>\n<pre><code class=\"language-text\">Output extent: B5\r\nOutput resolution: B5<\/code><\/pre>\n<p>For Sentinel-2 B8\/B4, remember that the bands have different native spatial resolutions depending on the products and bands involved. Your workflow should ensure that the input rasters are aligned\/resampled appropriately before combining them.<\/p>\n<p>Then click <strong>OK<\/strong> or <strong>Run<\/strong>, depending on your QGIS version.<\/p>\n<p>QGIS will create a new raster in which each pixel contains an NDVI value.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"6_Apply_a_Color_Ramp_From_-1_to_1\"><\/span>6. Apply a Color Ramp From -1 to +1<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>Your newly created NDVI raster may initially appear as a grayscale image. A color classification makes the vegetation patterns much easier to interpret.<\/p>\n<p>Right-click your NDVI layer and select:<\/p>\n<p><strong>Properties \u2192 Symbology<\/strong><\/p>\n<p>Change the rendering method to:<\/p>\n<p><strong>Singleband pseudocolor<\/strong><\/p>\n<p>Then set the classification range approximately from:<\/p>\n<pre><code class=\"language-text\">Minimum: -1\r\nMaximum: +1<\/code><\/pre>\n<p>A common visualization is to use a ramp that progresses from low NDVI values toward increasingly strong vegetation values.<\/p>\n<p>For example:<\/p>\n<table>\n<thead>\n<tr>\n<th>NDVI range<\/th>\n<th>Typical interpretation<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>-1 to 0<\/strong><\/td>\n<td>Water, clouds\/shadows, or other non-vegetated surfaces<\/td>\n<\/tr>\n<tr>\n<td><strong>0 to 0.2<\/strong><\/td>\n<td>Bare soil, rock, built surfaces, or very sparse vegetation<\/td>\n<\/tr>\n<tr>\n<td><strong>0.2 to 0.8<\/strong><\/td>\n<td>Increasingly dense\/healthy green vegetation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>These ranges are <strong>guidelines, not universal physical thresholds<\/strong>. Soil background, atmospheric effects, crop type, season, shadows, and sensor characteristics can all affect NDVI.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/CJcg0JDzS5MjI66Uy8FcE5HTptK9u-sfzCYX3z5UXEzF7fzhHgIcL_cW_8TqjJIlCHLpFBwQRPWWUGdrp96WYBfeBDy3hh__wMYLAxb348NO_tGHYKIk1mlcPhmqQsHuO5Oqld6jJVa7zK4BdWdFdLL6S4WKWYCJ6GmqRcqFhrNxnj8_cvCfjX2xzuTqv1lE?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/8L9Fl5kmb-hDKVH80o846ItM3qCemgeaXE4bqyVKyqyNOzn9jbV6A_ag8D3mP2-B8fu_itDxLIwEKOKtLP6ZByKPACTGz0e-Y6JByfOzX13iDdI_S1J2tbQimVU5s39ILxawA3ZiyTZ6SiN4JMy4EA5S7h46OwuoCMh84PQno26MNvASrFU9liGi9djsXXPj?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/H3QURGIMDiRuSSzEJLp1ZQ5SKQr0Z_mocAzNHViXI-HKg0iQGoRjKRpaHjVN2dQWzetGnJFhVljAm_hwwhV78KYZDNL_Hq92NqgXHbC8JeYRgM1FEejVEFol3KCtnOgUz3wxTi-1L19ClU4LhkI-uAlIZh4uo-eCzBGeR47KAPiCR61dsbZKRTVgdXkgFx1U?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/1Bjn0e24Ok44djaE_rVl-VAxYsHyjt-7FHcXT-UfjuXC3aoo88IY5iQbwFe5Z88XGEjPHsyB4Fc9trlH7SDykWJ6MG41-PnI5U4ZEZ0Pv-CddyCG2hkXYKSS-QZSaHc6GtLU-_Htldf60bCSFc3Y_l58fJronYRKuguvFQQ5g38VFSRZqXt0Ve0zD8XxNeoJ?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/OkIWQUt0atPNM6W7P7CY1rl37EJbfb7dX87pL6qpJ0MDbIjb86vii5ZSsJwDvTBlzMo_ueN1UCrZ3jfRPTBCPwziz0FYZjCsBmTx-TZbKmhHZnYHKXJxsEtNuwMR6dRk1Lt3-UU9sD-bhKG01O00WQ5CFonifh3sKEa-_uS1aD5_Uuw5myMnUzIZa3XGs3jA?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/images.openai.com\/static-rsc-4\/9HNhGblA2un-77Y40PN6HryoVCkKT5_r7POZi4kyz6qnEAeZzAojLolm7-Qus4eSguENAlMiz7hS9K0CXb0Ac2AzL1PjXidROdItLdMsDKmvJpsOsym0v_EU5xIrR3GAModgMdKk-VxDFAryVq8A4s8_GFngvD-LE2krsyOX_QryILu3U-R-jYTSR6u5IcZZ?purpose=fullsize\" alt=\"Image\" \/><\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"7_How_to_Interpret_Your_NDVI_Map\"><\/span>7. How to Interpret Your NDVI Map<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>Once the pseudocolor classification is applied, you can begin relating pixel values to actual ground cover.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"-1_to_0_Water_and_non-vegetated_surfaces\"><\/span>-1 to 0: Water and non-vegetated surfaces<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Negative NDVI values are commonly associated with:<\/p>\n<ul>\n<li>Lakes and rivers<\/li>\n<li>Wet surfaces<\/li>\n<li>Some cloud\/shadow pixels<\/li>\n<li>Other surfaces where Red reflectance exceeds NIR reflectance<\/li>\n<\/ul>\n<p>Water commonly produces strongly negative values.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"0_to_02_Bare_or_sparsely_vegetated_surfaces\"><\/span>0 to 0.2: Bare or sparsely vegetated surfaces<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Low positive values can indicate:<\/p>\n<ul>\n<li>Bare soil<\/li>\n<li>Sand<\/li>\n<li>Rock<\/li>\n<li>Urban surfaces<\/li>\n<li>Dry or sparse vegetation<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"02_to_08_Vegetation\"><\/span>0.2 to 0.8: Vegetation<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Higher positive values generally indicate greater amounts of green vegetation.<\/p>\n<p>Examples include:<\/p>\n<ul>\n<li>Grasslands<\/li>\n<li>Cropland<\/li>\n<li>Shrubland<\/li>\n<li>Forest<\/li>\n<li>Dense agricultural vegetation<\/li>\n<\/ul>\n<p>Very high NDVI does not automatically mean that vegetation is &#8220;healthy&#8221; in every biological sense. NDVI is primarily a spectral indicator of vegetation greenness and density.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"8_Troubleshooting_Common_NDVI_Problems\"><\/span>8. Troubleshooting Common NDVI Problems<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<h2><span class=\"ez-toc-section\" id=\"Problem_1_Your_NDVI_values_look_like_integers\"><\/span>Problem 1: Your NDVI values look like integers<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>A common problem occurs when the calculation produces an integer raster instead of a floating-point raster.<\/p>\n<p>NDVI requires decimal values such as:<\/p>\n<pre><code class=\"language-text\">-0.35\r\n0.12\r\n0.47\r\n0.76<\/code><\/pre>\n<p>If your output is restricted to integers, much of the useful NDVI information can be lost.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Solution\"><\/span>Solution<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Check that your input\/output raster data type supports floating-point values.<\/p>\n<p>In the Raster Calculator\/output settings, choose an appropriate floating-point data type where available, such as:<\/p>\n<pre><code class=\"language-text\">Float32<\/code><\/pre>\n<p>This allows decimal NDVI values to be preserved.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"Problem_2_Strange_values_caused_by_division_by_zero\"><\/span>Problem 2: Strange values caused by division by zero<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The NDVI equation contains:<\/p>\n<p><span class=\"katex\">NIR+RedNIR + Red<\/span><\/p>\n<p>in the denominator.<\/p>\n<p>If:<\/p>\n<pre><code class=\"language-text\">NIR + Red = 0<\/code><\/pre>\n<p>the calculation attempts to divide by zero.<\/p>\n<p>This can create:<\/p>\n<ul>\n<li>NoData pixels<\/li>\n<li>Invalid values<\/li>\n<li>Artifacts in the resulting raster<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Solution-2\"><\/span>Solution<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>You can protect the calculation using a conditional expression.<\/p>\n<p>Conceptually:<\/p>\n<pre><code class=\"language-text\">IF(NIR + Red = 0, NULL, (NIR - Red) \/ (NIR + Red))<\/code><\/pre>\n<p>For example, a QGIS expression can be structured as:<\/p>\n<pre><code class=\"language-text\">if(\r\n    (\"B5@1\" + \"B4@1\") = 0,\r\n    NULL,\r\n    (\"B5@1\" - \"B4@1\") \/ (\"B5@1\" + \"B4@1\")\r\n)<\/code><\/pre>\n<p>Adapt the band names to your actual raster layers.<\/p>\n<p>This tells QGIS:<\/p>\n<blockquote><p>If the denominator is zero, return NoData; otherwise calculate NDVI normally.<\/p><\/blockquote>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"9_Other_Reasons_Your_NDVI_Map_May_Look_Wrong\"><\/span>9. Other Reasons Your NDVI Map May Look Wrong<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>If your map contains unexpected patterns, check these before assuming the formula is incorrect.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Check_your_band_selection\"><\/span>Check your band selection<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>For Landsat 8\/9:<\/p>\n<pre><code class=\"language-text\">NIR = B5\r\nRed = B4<\/code><\/pre>\n<p>For Sentinel-2:<\/p>\n<pre><code class=\"language-text\">NIR = B8\r\nRed = B4<\/code><\/pre>\n<h3><span class=\"ez-toc-section\" id=\"Check_that_the_bands_come_from_the_same_scene\"><\/span>Check that the bands come from the same scene<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Don&#8217;t combine:<\/p>\n<pre><code class=\"language-text\">B4 from June\r\nB5 from August<\/code><\/pre>\n<p>unless you specifically intend to perform a multi-temporal analysis.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Check_spatial_alignment\"><\/span>Check spatial alignment<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>The two rasters should have compatible:<\/p>\n<ul>\n<li>Extent<\/li>\n<li>Pixel size<\/li>\n<li>Grid alignment<\/li>\n<li>Coordinate reference system<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Check_preprocessing\"><\/span>Check preprocessing<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Clouds, cloud shadows, atmospheric effects, and other artifacts can appear in an NDVI map and may be mistaken for vegetation changes.<\/p>\n<p>For serious <strong>vegetation health analysis<\/strong>, consider using appropriately processed surface-reflectance imagery and masking clouds and shadows before calculating NDVI.<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"10_Complete_NDVI_Workflow_at_a_Glance\"><\/span>10. Complete NDVI Workflow at a Glance<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>You can remember the entire QGIS workflow as:<\/p>\n<pre><code class=\"language-text\">Satellite imagery\r\n       \u2193\r\nIdentify Red + NIR bands\r\n       \u2193\r\nLoad rasters into QGIS\r\n       \u2193\r\nCheck alignment and preprocessing\r\n       \u2193\r\nOpen Raster Calculator\r\n       \u2193\r\n(NIR - Red) \/ (NIR + Red)\r\n       \u2193\r\nSave as Float32 NDVI raster\r\n       \u2193\r\nApply Singleband Pseudocolor\r\n       \u2193\r\nClassify approximately -1 to +1\r\n       \u2193\r\nInterpret vegetation patterns\r\n       \u2193\r\nPerform environmental\/agricultural analysis<\/code><\/pre>\n<h2><span class=\"ez-toc-section\" id=\"Quick_Reference\"><\/span>Quick Reference<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<table>\n<thead>\n<tr>\n<th>Task<\/th>\n<th>Landsat 8\/9<\/th>\n<th>Sentinel-2<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Red<\/strong><\/td>\n<td>B4<\/td>\n<td>B4<\/td>\n<\/tr>\n<tr>\n<td><strong>NIR<\/strong><\/td>\n<td>B5<\/td>\n<td>B8<\/td>\n<\/tr>\n<tr>\n<td><strong>Formula<\/strong><\/td>\n<td><code>(B5-B4)\/(B5+B4)<\/code><\/td>\n<td><code>(B8-B4)\/(B8+B4)<\/code><\/td>\n<\/tr>\n<tr>\n<td><strong>QGIS tool<\/strong><\/td>\n<td>Raster Calculator<\/td>\n<td>Raster Calculator<\/td>\n<\/tr>\n<tr>\n<td><strong>Expected range<\/strong><\/td>\n<td>-1 to +1<\/td>\n<td>-1 to +1<\/td>\n<\/tr>\n<tr>\n<td><strong>Visualization<\/strong><\/td>\n<td>Singleband Pseudocolor<\/td>\n<td>Singleband Pseudocolor<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"Final_Takeaway\"><\/span>Final Takeaway<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Calculating NDVI in QGIS is essentially a three-part process: <strong>identify the correct Red and NIR bands, calculate the normalized difference, and visualize the resulting -1 to +1 raster<\/strong>. For Landsat 8\/9, use <strong>B5 and B4<\/strong>; for Sentinel-2, use <strong>B8 and B4<\/strong>.<\/p>\n<p>Once you have the NDVI raster, you can take the analysis further by calculating <strong>mean NDVI by agricultural field, comparing vegetation between dates, detecting crop stress, or combining NDVI with land-use and environmental datasets<\/strong>.<\/p>\n<p>Available next action: Create a downloadable DOCX file here in this chat containing the editable prose above<\/p>\n","protected":false},"excerpt":{"rendered":"<p>How to Calculate NDVI in QGIS: A Step-by-Step Guide for Students If you are learning how to calculate NDVI in QGIS, you are working with one of the most widely used vegetation indices in remote sensing. The Normalized Difference Vegetation Index (NDVI) uses the relationship between Near Infrared (NIR) and Red wavelengths to estimate the &#8230; <a title=\"How to Calculate NDVI in QGIS: 10 Easy Steps\" class=\"read-more\" href=\"https:\/\/helpwithmygisassignment.com\/blog\/how-to-calculate-ndvi-in-qgis\/\" aria-label=\"Read more about How to Calculate NDVI in QGIS: 10 Easy Steps\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-384","post","type-post","status-publish","format-standard","hentry","category-civil-engineering"],"_links":{"self":[{"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/posts\/384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/comments?post=384"}],"version-history":[{"count":3,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/posts\/384\/revisions"}],"predecessor-version":[{"id":417,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/posts\/384\/revisions\/417"}],"wp:attachment":[{"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/media?parent=384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/categories?post=384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/helpwithmygisassignment.com\/blog\/wp-json\/wp\/v2\/tags?post=384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}