White Pine

These maps of the study points were made with Landsat images taken from the  ESRI Landsat Explorer.

The Landsat imagery is considered medium resolution and is designed to show a larger area. Most of the bands are 30 meter resolution. According to the ESRI website:

This band combination (4,3,2) approximates the spectral range of vision of the human eye, and has been pansharpened using the 15m panchromatic band. Here the 30m natural color imagery has been pansharpened using the 15m panchromatic band in order to achieve better imagery resolution. This Landsat band combination is well suited for broad-based analysis of both terrestrial and underwater features, and for urban studies. This true-color composite approximates the range of vision for the human eye, and hence these images appear to be close to what we would expect to see in a normal photograph. Natural color images tend to have low contrast and are somewhat hazy in appearance. This is because blue light is more susceptible than other bandwidths to scattering by the atmosphere, however, it penetrates clear water deeper than the other bands, and is well suited to analysis of underwater features, Healthy vegetation is green, recently cleared fields are very light, unhealthy vegetation is brown and yellow, roads are gray, and shorelines are white.

The above map shows the near infrared band. Here is the technical description:

This band combination (5,4,3) gives results similar to traditional false color infrared photography. This band combination gives results similar to traditional false color infrared photography, which adds a near infrared (NIR) band and drops the visible blue band. Vegetation in the NIR band is highly reflective due to chlorophyll, and a NIR composite vividly shows vegetation in various shades of red. Urban areas are cyan blue, and soils vary from dark to light browns. Ice, snow, and clouds are white or light cyan. Coniferous trees will appear darker red than hardwoods. Generally, deep red hues indicate broad leaf and/or healthier vegetation while lighter reds signify grasslands or sparsely vegetated areas. Water appears very dark, due to the absorption of energy in the visible red and near IR bands.

The last map is optimized for a view of agricultural resources.

This band combination (6,5,2) is good for agricultural studies. In this band combination, vigorous vegetation appears bright green, healthy vegetation appears as a darker green, while stressed vegetation appears dull green. Coniferous forests appear as a dark, rich green while deciduous forests appear as a bright green. Sparsely vegetated and bare areas appear brown and mauve.

Usually hillshades from a DEM are visualized from the northwest. Here I tried it both from 315 degrees (NW) and due south, 180 degrees. The results are very different. The topography of the lake appears inverted with the azimuth of 180. That is, the reservoir appears above the landscape.

Here is the contour map with a contour interval of 20 feet and an index contour every 100 feet. In ArcMap I made two separate contours.

This video from Oregon State University is one of the best explanations of how to interpret remotely sensed imagery. It talks mostly about aerial photos, but it applies to other kinds of imagery, too.

Following are notes on infrared imagery.

Here is a link to an infrared photography group on Flickr. It has black and white and false color imagery.

Near Infrared or False Color Maps for Study Sites
General Instructions

In this assignment we will use the NAIP imagery to generate true color and false color maps of our study sites. Here are semi-detailed instructions.

• Go to the PASDA Imagery Navigator (Go to www.pasda.psu.edu and choose Apps & Tools). Navigate to each of the study site points.
• Right click near each study site to bring up the PASDA Download Links. Choose the 2017 Statewide Infrared & Natural Color 4-band (1m). Click here to see what the screen looks like.
• Download the tiff files for NE Waynesboro, NW Iron Springs, and SW Caledonia.
• Extract them to the T drive like we did for the panchromatic imagery.
• Open ArcMap. Load each image layer twice and use the instructions below to make one of them color and one false color.
• Display the study points on the map as we did last week. Click here to download the geodatabase of the study points if you don’t still have it.
• Choose two of the study sites to map.
• Make two 1:9600 maps of each site similar to what we did last week.
• Export your maps as jpg files.
• Write a report on your website that includes your maps.
• Upload a link in Canvas to get credit.
• Answer the questions below in your report.

How to show two colors from one image layer.

The NAIP imagery has both true color and infrared false color in the same file. When downloading the tiff from PASDA you get four bands.

By default:

• red is 1
• green is 2
• blue is 3
• near infrared is 4

In ArcGIS the raster property wizard can reassign the bands as needed.
For natural color the display the bands in the symbology are set as:

1. red — band 1
2. green — band 2
3. blue — band 3

Band 4 is not displayed

For CIR or false color, the bands should be shifted.

1. red — band 4
2. green — band 1
3. blue — band 2

Band 3 is not displayed. Try experimenting by showing different combinations or just one layer. As long as the red band is near infrared you can experiment with the others.

Questions to Address in Your Report

• How does the vegetation differ between the two views?
• How does hardwood vs. softwood vegetation compare?
• How do bodies of water compare between the two views?
• What time of year is NAIP recorded? Does this have an effects on what you see?