Ready to get started in Lens or further expand your understanding of remote easement monitoring? This step-by-step, interactive lab will help you become an expert user of Lens, in just about 30 minutes. We’ll be using Lens to monitor a sample conservation easement and leveraging different true color imagery options.
To follow along with this Lab, you’ll need to have a Lens account—either Lite, Standard, or Enterprise. Sign up for Lens and get started today!
At the end of this lab you will know how to:
For this lab, imagine it’s 2022 and you work for a land trust where you have a conservation easement that was recently transferred from another organization, and you want to understand the history of this property since it became a conservation easement in 2015. Your job is to review the property and document any changes across the property since 2015.
Add a new portfolio from the Lens homepage, or navigate to the portfolio you want to add this property to and select ‘Add Property’.
If you have a Standard or Enterprise account, click on ‘Select US tax parcels.’ Then, In the map’s search bar, search ‘1845 Green Hill Road, Lansdale, Pennsylvania 19446’. Click on this area to start your property selection. Now zoom out until you can see Green Hill Rd and Meadow Ln to the southeast; view the image on the next page for reference. Hold down shift on your keyboard and continue clicking tax parcels until it matches the property in the image below. There should be 8 tax parcels to click on in total.
If you have a Lite account, click on ‘Draw on the map.’ In the map’s search bar, search ‘1845 Green Hill Road, Lansdale, Pennsylvania 19446’. Zoom out until you can see Green Hill Rd and Meadow Ln to the southeast. Click on the ‘Draw’ button and draw a shape similar to the image below.
Name the portfolio and property and click ‘Review Datasets.’
In the pop up window we can browse different datasets available in Lens and click on a layer’s card to see more details. Since this lab mainly focuses on truecolor imagery we don’t need to select any additional datasets.
Exit the pop-up and click confirm to kick off processing.
The property will begin processing - it should typically only take about 7 minutes before you can proceed with the lab, although in some cases it may take longer. You should receive an email when your property is finished processing.
Lens defaults to showing you the most recent high resolution truecolor image - which should be an image from 2022. This image is publicly available from the USDA’s National Agricultural Imagery Program (NAIP). This program has been running since 2003 and provides 1-meter resolution imagery during the growing season for the contiguous US. Each location in the contiguous US has coverage from this program roughly every other year.
💡Did you know? NAIP imagery is aerial imagery which means it is captured by aircraft closer to the earth than satellites. Because aerial imagery has less atmospheric interference, the image quality is often crisper.
Use Compare mode to view the 2015 and 2022 NAIP images and see what changes have occurred here. In the eastern half of the property there are two main areas with vegetation change: tree planting activity in the southeast corner and natural revegetation of a farm field to the north. In the western half of the property there are also two main areas of change to note: the house from 2015 has had significant expansion along with surrounding vegetation changes and there is also a new house that has been built. Make notes to capture these changes.
✨Tip: if you draw an area for your note location you can quickly see the size of the area of change.
We know there was a new house constructed on this property between 2015 and 2022, but let’s try to pinpoint the timing of construction - we can use Analysis to do so.
Open the Analysis pane in Lens. Leave ‘Draw area’ selected and draw a shape around the new house. Make sure the dataset for analysis is Vegetation (S2), chart type is Average Value, and set the Time range to 'All Time'. Click 'Analyze' and wait for the chart to load.
What do you notice about the vegetation chart? Is there a significant difference between one summer peak and the next? Click on a point from summer 2016 and then shift-click on a point from fall 2016 after vegetation values start to decline. Does this look like typical seasonal vegetation decline or does it look like the result of construction?
Click ‘Add Note’ and type your observations from the vegetation chart and layers and your estimated timing of construction. Then click ‘Create’ to save your observations as a note.
For this next section of the lab, let’s fast forward to present day and monitor for changes between 2022 and 2024.
❗NOTE: this portion of the lab covers ordering imagery and will cost about $5 if you want to order the imagery. If you don’t want to spend any money this section still provides useful guidance about reviewing available imagery from the order pane and selecting the best option for purchase.
We want to purchase some recent high-resolution imagery for our 2024 monitoring. Let’s explore the options in the Order pane to decide which image makes the most sense for us to purchase.
You should see a number of options from 2024 in the order pane. Scroll down to the earliest 2024 image and you’ll see one from February 16th. Click on that image to preview it. Here we can see that despite this image having 0% cloud cover, it is clear that there is snow on the ground in the image. Additionally, there is a large red section indicating that this image doesn’t cover our entire property - so it’s probably not an ideal image to purchase in this instance.
Next we see a Nearmap image from March. This image looks good and is free of clouds or haze. In this image, the trees have not yet leafed out. In some cases this is ideal for monitoring, but in our case since we have an image from May 2022 with leaf-out conditions we ideally want to compare to another image from a similar time of year.
The third image from 2024 we see is a May image from Airbus. Previewing this image we see full coverage of our property, 0% cloud cover, and no major shadows or anything of concern. This looks like a really good option, but let’s check the rest of our options in the order pane before purchasing.
We see a lot of Airbus extended archive options in the order pane. The extended archive is a great way for us to surface additional options for you in the order pane, but this data is unlike other Airbus data and other vendor data in that it does not receive the same level of verification and correction. Since this quality control step is removed, more imagery is made available, but there is a greater chance of lower quality scenes. This imagery also takes longer to appear in Lens after you’ve ordered it. For this reason we recommend (1) that you take extra care to preview extended archive imagery, and (2) you allow a few days before you need the imagery for monitoring. When reviewing this imagery, pay careful attention to clouds, cloud shadows, and possible color distortion.
There is also a June Nearmap image in the order pane. Similar to the May Airbus image, this image has full coverage of our property, 0% cloud cover, and no major shadows or anything of concern. This image appears to be a great option as this thumbnail shows good contrast and Nearmap provides aerial imagery which we know tends to be nice and clear. Let’s purchase this one! It might take a few minutes for the image to process.
By now you should be an expert in spotting changes using Compare mode. View Compare mode with the 2022 NAIP image and the 2024 Nearmap image you just ordered.
What changes do you see? Make notes to document your observations.
✨ Hint: you might notice some vegetation growth, some vehicle tracks in a field, and some small changes around one of the houses including a new location for a playground and trampoline.
You should have a number of notes documenting the many changes on this property since 2015. Let’s collate everything into a report.
At the top of the Notes pane, click the page icon to create a report.
Use our Smart Summary feature to automatically generate a summary for the report based on all of your notes. Review and edit the summary as you see fit.
Scroll through your report and make any edits you see fit to page titles, map zoom, or scale bar visibility. Save your report and/or export to pdf, and you're finished!
Great job on completing your easement monitoring lab in Lens! Contact us at lens@upstream.tech with any questions.
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