Welcome to the EROS User Experience webinar series, where we talk to staff at Eros to learn more about the data, tools and services coming out of the USGS Earth Resources Observation and Science, or EROS Center. Today's webinar is titled Landsat Special Requests: Expanding Acquisition Capabilities. I am your host, Danielle Golon. The Remote sensing user Services lead here at EROS in Sioux Falls, South Dakota.

The time is currently 12 p.m. central, so let's go ahead and get started. First, a few logistics to ensure the best audio experience. All participants have been muted. If you have any questions or comments during the webinar, please use the Q&A feature, which can be found under the more settings if you do not see it currently. If this feature does not work for you, please feel free to enter your questions or feedback into the chat, and we will address all questions and feedback at the end of the webinar.

If you cannot use the Q&A feature or the chat due to your organization settings, please feel free to email your questions to conserve at USGS gov. That is custserv@usgs.gov and we will answer them there. Today's webinar is being recorded. The recording will be available later on the USGS Eros User Experience Webinars web page.

At the start and end of the webinar, we will have a few polling questions. These polls are optional, but your answers can help us create a better user experience in the future. The polls questions will be available via the polls feature and teams, and I also have added them to the team's chat for our audience members who are not able to use the team's polls feature due to their organization settings.

If the polls feature is not working for you, please feel free to respond to the questions in the chat instead. The questions are the same, so please either use that polls feature or the chat, whichever option works best for you. At this point, you should now be able to see the first set of polling questions. Please feel free to fill those out at your leisure.

We will leave them open during the entire webinar. Today's webinar will consist of a presentation, several live demonstrations, and then a question and answer session. Today's speaker is Jacob Savoy. Jacob is a Landsat User services specialist here at the Aero Center. Jacob is a contractor serving as the primary User Services representative for Landsat related inquiries, where Jacob provides front line support to the user community on topics ranging from general Landsat data questions to troubleshooting the USGS machine to machine or M to M API.

Jacob holds a master's of Science in Geographic Information Systems, or GIS, from John Hopkins University, and has spent the past five years supporting the Eros User Services team. We also have several Aero staff members from User Services and the Landsat team here at Eros on the line to help answer any questions you may have. After Jacob has finished his presentation again, please feel free to add any questions or feedback throughout the webinar using that Q&A feature in teams or the webinar chat.

We will try to answer all questions within the time allotted, but if we are not able to address your question during the final Q&A portion of the webinar, we will follow up with you offline. And if there is a future webinar topic you would like us to cover. Please feel free to suggest that as well. With that is my pleasure to introduce today's speaker, Jacob Savoy.

Take it away, Jacob. So, as Danielle said, my name is Jacob Savoy, and we're gonna be talking about Landsat special requests and how you can get involved to expand the imaging capabilities for your own research. So before digging into the special request, wanted to give some background information on Landsat and our standard acquisition plan. So for Landsat 8 and Landsat 9, they each acquire about 750 scenes every day, with their main focus being on continental landmasses and nearshore coastal zones.

For Landsat, daytime imagery is the most common type of imagery that we acquire, since both our Operational Land Imager and Thermal Infrared Sensor All in tears are able to acquire data, and historically, that means a mean equatorial crossing for each of the satellites is about 10:12 a.m., plus or minus about five minutes local time. This is a map of what our acquisition plan looks like, and so we give different priorities to different areas on Earth.

This is our descending or daytime acquisitions. So as you can see, as I said we focus mainly on continental landmasses and then near shore. However, we do have images going up towards the poles, small islands, that kind of stuff that we do put a priority on. You can see just because of daylight hours, there's kind of a cutoff, both north and south, that there is a lower priority.

However, that is made up for our ascending or nighttime acquisitions where there is a higher priority on those polar regions. And that's just due to the rotation of the Earth and how the satellites orbits are set. We are able to get even lit images, even at night, just because of how the summer solstice works. So what is a Landsat special request?

They are an opportunity for the scientific community to task the Landsat satellites outside of the nominal acquisition plan, so they are able to get imagery at night when there is less priority, or over oceans or whatever that might be. And this goes into a couple common reasons. So as I said, nighttime polar and then ocean or just images that are not in the standard acquisition plan or that the scientific community has a specific interest in that we need to place a higher priority on.

I have a couple examples of these. So for this first one, we're looking at a nighttime image over Phoenix, Arizona. This was collected the 24th of October in 2025. And a reason somebody might want a image like this as they are studying nighttime urban heat index. And again, Phoenix being in the southwest US has that kind of high capacity for heat.

So as you can see on the left there, that is just an image from band two that would come from the OLI sensor, because we're not getting that visible light being reflected during the night. You really don't get much information there. However, band ten, which is our thermal infrared, you can see the outline of Phoenix proper, the mountains surrounding it, some of the reservoirs that feed into the system, and you're able to zoom in and see things like individual streets, buildings, that kind of stuff.

Did provide a second example here. This one is a near polar example, also taken at night. This focuses on Ellesmere Island up in Greenland. This is a two part example. This first part we're looking at image from August 5th of 2017. And again due to how the satellite path works, this image was actually acquired about 2:45 p.m. local time.

Somebody might want a image like this if they are studying ice extent up in this area. And so I will show this first image on the left is over Greenland with this pink area showing where that scene was acquired. And then the image on the right is that scene. You can see it is very snowy, very icy, but we do see a lot of that rock outcropping.

And this is the second part of that. Again, same location. However this one is later in a season. I was looking for cloud free imagery for this demonstration, so we jumped all the way to 2023 in September. And again, this is about 2:50 p.m. local time when the image was acquired. As you can see, there is much heavier snow ice cover.

You can still see the outline of some of those rock outcroppings. However, they are mostly covered at this point in time. Just for visual comparison. Again 2017 to 2023. And again, one of the reasons you might look at exploring something like this is to look at ice extent. And so maybe looking at that thermal data. So as you can see on the left image that is the 2017 looks like those landmasses, those rocky outcroppings are actually warmer than the surrounding areas.

However, when you have greater ice extent in that 2023 image, those values basically flip on each other and the water ice areas are actually showing as a warmer temperature there.

As a part of that polar acquisition, we did institute a extended acquisition of our polling areas, and these focus on the Arctic, Antarctic and Greenland areas, and they are covered under something called our leap. Just to give a little understanding on that, I did pull some images here that show again our increased priority. So you can see the Antarctica, Greenland and Arctic region and how that leap plays out in those different areas as a part of special request.

We do have ongoing annual requests. So if you are interested in any of these topics, these are things that are already covered. So you don't necessarily need to submit your own. We have a annual volcano campaign that is global. So a lot of the volcanoes, again, because there's lots of research being done there. We don't necessarily know when they're going to erupt or that kind of things.

We are acquiring images whenever the satellites pass over those locations, as well as Ellesmere Island. That was in those previous demonstrations, the Arctic and Antarctic areas that are covered by the leap. And then there is a large western US and Alaska campaign that we collect imagery at nighttime during the fire season. So if you're looking at acquiring any imagery, we do have this acquisition tool.

And so well, that will do is you can select either the ascending or descending pathways, and that will give you an estimate of which satellite as well as which dates would be covered by your area of interest. And I have a couple of zoomed in pictures here that will go over in just a second. So these in blue are going to be the descending or daytime scenes.

As you can see, they kind of go from the northeast down to the southwest and then kind of have that same sort of curve once they get towards the South Pole, just because of the pathway of the satellite. This would be for I believe this is today that I got this screenshot for. So this is what the path for the daytime imagery looks like today.

And then the anticipated nighttime acquisitions in green here again they kind of reversed that direction because there's that looping pattern that kind of go from the southeast to the northwest. In this instance. We do have a video here showing the pathways. This is just for Landsat eight and just during the daytime.

So using that acquisition tool, this is kind of just a zoomed in version. And I'll leave it here for a couple of seconds. Again this is our pending acquisitions for today. So you can kind of see where the satellites might pass over and then get an estimate of, you know, if you are interested in that area, what kind of timeline you might be looking at.

All right. So digging into the special requests where to find those forms, they are on our Landsat acquisitions web page, specifically under the Special Request for future Landsat Acquisition section, we have both a single path row request form if you're looking just for imagery over a single area. But we also have a multiple path row request form where if you are looking at an area of interest that covers more than a single path row, or you were looking at multiple areas of interest at the same time, you can submit that all in a single request.

As far as the single path row request form. We will go over that here shortly. I've got a example pulled up, but we're basically asking questions like who are you? What are you interested in studying? What satellites do you want to use that kind of stuff. And then as far as the multiple path request form goes, it is basically the same questions.

It's just on a word document so that you could submit multiple path rows in that form. And the reason we offer that is to make it easier for you. So rather than submitting 4 or 5, six, ten, a dozen single path row request forms and entering all that information at the same time, you only have to enter it once, and then it also allows us to keep all of your information one place.

So if there's ever any questions you need to make changes wish to extend, then we're only looking at one request rather than however many you needed to submit when submitting the multiple path row requests. We do also require that you submit a CSV file, and that can also be linked on that form where we saw the both single and multiple path row request forms, and that is a requirement for it to be submitted.

Now let me flip over. I have pulled up our single path row request form here and I will zoom in. So this is what it looks like. Like I said, it's pretty basic information we're looking for when you're submitting the request. Your name, what company or agency you're associated with, whether that's a university, a company, a research group, whatever that might be your telephone number, a good way to contact you, the type of request, whether you're working for a government entity, a university, a research group, whatever that might be, which sensor you would like imagery from most commonly people because of the availability, will request from both a general outline of which path rows you are looking at a date range for when you are hoping to get imagery from, and then a short little blurb about what you intend on using that Landsat imagery for. So, like in this case, those path rows cover Sioux Falls, South Dakota, and a reason why you might be interested looking at urban heat over the city as well as the surrounding areas.

So as I said, this is our multiple pathway request form. When you do submit that, we are looking for that additional CSV and all that, that is, is basically the path rows listed out as that can be fed into our system and uploaded. So there is no potential issue for clerical areas, mistranslations, anything like that.

What to expect when you do submit a form. So as you fill them out you should send it to our USGS User Services group when we receive that from you. You should expect an email from us when the request is submitted and that should be coming from that serve at USGS gov email. And then as it works through the approval process and again as the request is about to expire, we do send automated emails just to kind of let you know where things are at.

If the request is approved, data acquired from the satellites is posted to our Earth Explorer and other USGS data portals where applicable. And then as the request is about to expire, you will receive emails reminding you of that expiration. Those emails are. Reminder if you have a ongoing campaign you wish to extend, that is your chance to message us to get a new request submitted.

And we do send those out about seven days beforehand. And that's just so we make sure that there are no gaps in your acquisition imagery, so that you don't miss a chance at catching whatever you're studying. If the request is denied, you should receive an automated message from us informing that the request was denied. If at any point you have questions regarding the status of the request, you need to make changes.

Wish to extend? Again, please email our User Services group at that serve at USGS gov email. As far as timelines and when to expect things. Once you send a request to us, it is usually submitted within a couple of days. Just depends on what else is going on, what priorities are, how many requests we have coming in, that kind of stuff.

Approval usually happens within about two weeks. We do suggest that you submit earlier than two weeks, because it does take time for the request to be passed through approval processes and then up to the satellite. And so you should always plan on submitting at least two weeks before your first anticipated acquisition. You can submit sooner than this. So if it is approved, then acquisitions will start coming down on whatever that first date of the request is.

When you should start seeing imagery is either the first pass of the satellites after it has been approved, or after that first start date. If you submitted early, and then you should expect to get those expiration reminders starting every day about one week before the expiration. There are some limitations to the special request so the scientific community can make requests.

The public can submit requests as long as they go through the same process. But priority is always going to be put on research oriented focuses. If you're looking at studying something, if you're submitting for something like, hey, I want an image over my house on this specific day that has a higher likelihood of getting denied. As far as limitations, we also have a timing limitation.

So as I said on the last slide, we need time to submit and approve the request and send it up to the satellite. So we do suggest submitting about the two weeks early and then request can only run for about a year. Anything longer will have to be renewed, but that will go through the same process. You could submit the same forms just with updated dates, and then our Landsat ground stations can only ingest so much data.

So if you have a huge request or there are a lot of requests going out at the same time, there is the possibility of getting denied just based on what those priorities are. And then approval because of there are multiple steps in the approval process. Requests can be denied for any reason. We do our best to find out what those are, but if a request is denied, ultimately it's denied.

We can try. But that's kind of where it ends as far as accessing the data or finding it once it has been acquired. One of the best places to do so is on our Earth Explorer page. I have a couple slides here in case things aren't working right, but otherwise let me flip over to a browser and we'll do this live.

So that fake request we did, we focused over Sioux Falls, South Dakota. That's kind of where our Eros Center is located. So when you're on our Earth Explorer page, if you want to set a area of interest, all you've got to do is find the map, zoom in to where you want to be, and you can click. And that should set a Pin.

If you click multiple times, you should start drawing a polygon. Otherwise, if you know what specific path row you are interested in, there is this. Select a geocoding method and you can go from feature to path row. And so for like Sioux Falls I know we are looking at path 123 row 214. And it should also drop a pin in the center of where that scene would be.

If you are looking at a specific time frame like you've had a request going for any length of time, you can set your date range and cloud cover. However, you don't need to do that. We can then proceed to our data sets, and I would always advise first looking at our Landsat collection two level one and Landsat eight nine are the only ones that are acquiring at this time.

So if we're looking at that example request, we're going to be looking for that data. And the reason we suggest that collection two level one is because in order to get process to level two, there is certain accuracies and information. We need to be able to process it to the higher level. So some of that is missing when we miss out on that Oli imagery.

So I always recommend starting with the level one product. Then again, as most of our special requests are going to be nighttime imagery, you can proceed to this additional criteria tab here. And there is a day night indicator. And so we can look specifically for nighttime imagery. When we hit our results it should load here. And as you can see one second let me redo this here.

Like we were getting too many results there. So let me make sure we're getting the right information.

There we go. That looks better. Currently I am not logged in. If you wish to download something you will need to be logged in, but you can preview the imagery here and see where it might be. And again, see if that fits your needs based on that acquisition.

Flipping back to our slides, like I said, you can view the data on Earth Explorer, but if you want to download anything, you're going to need to set up an account with our EROS registration system and be logged in. Setting our area of interest, selecting our data sets, selecting our additional criteria, and then preview and download as you are logged in.

If you ever need assistance navigating Earth Explorer, one of our other webinar walks you through it. We have a link here. I believe these slides will be shared, otherwise it can be found on the help page of Earth Explorer. As far as additional resources, I have linked to both our long term acquisition plan, that information as well as our extended acquisition plans.

You can see where those areas over the polar regions are. And that kind of wraps us up. If you have questions, please feel free to reach out to us. You can email us at our serve at gov email. Give us a call at (605) 494-6151. During our service hours, which are 8 a.m. to 4 p.m. Central Time. Otherwise, we have a User Services contact page on the USGS EROS website.

Thank you all for your time and I'll turn it back over to Danielle. And if you've got any questions, we can get those answered. Perfect. Thank you for a great presentation and for showing us those really cool demos. Jacob. For those listening in, I have added a few final links to the chat, which include more information about Landsat, as well as links to sign up for a few listservs, a link to watch some of our previously recorded webinars, and a few social media channels to follow if you are interested.

At this time, we'll now move on to the final optional Polling questions portion of the webinar and answering the questions we received during the webinar. We'll go ahead and post those polling questions in the chat and launch them. You should see those now on your screen or in the chat. Please take a few moments to respond to those questions.

Remember, they are optional. They are the same set of questions, so please only answer them once via the polls feature or in the chat. Whichever method works best for you based on your organization settings. And if you have any final questions or feedback about the data and tools covered today, or perhaps any data or tutorial ideas you'd like to see out in the future, please add those to the Q&A feature and teams or the chat now as well.

With that, we'll give you a few moments to answer the polling questions and submit any final questions or feedback you have for the team, and then we'll address those in a few minutes. All right. I do see some of the polling responses are coming in. So thank you to everyone answering those. Please feel free to continue working on those.

But for now we'll go ahead and start to feel some questions from the audience. The first question we have is is there an API to access the data instead of Earth Explorer? I can answer that. We do have our machine machine API, if you've got questions on that. We've got a couple good examples out there that if you reach out to our user services group at that email, we can send you links to that and get you started.

And there are ways to again, if you're looking at special request data, nighttime imagery, that kind of stuff, there are ways to filter that, to find just that imagery. Otherwise, all of our Landsat data, as well as most of our other USGS data is posted there so that you can access through the API. Perfect. Thank you. Jacob. We also have someone who puts in the chat.

One of the challenges for users is to get suitable ndVi data for the night tier image. In case of LST calculations. Are there any suggestions or advice on that? So that's going to be difficult, especially for nighttime because the Oli sensor does not collect enough reflected light to be able to get a clear image for the bands needed for ndVi.

Again, if you're looking at surface temperature, you can calculate, as I did in this example, brightness temperature of the pixels. But then again, you are dealing with atmospheric effects, and it's not going to be quite as accurate as our level two products. But for extended studies for getting a good glimpse of land surface temperature at night. This is an option for that.

Perfect. And we did have some feedback in the post question. The post poll question is what else can we do to improve the Landsat special requests? And the user mentioned send out some kind of awareness newsletter describing ongoing special request. This is such a cool service. Thank you. So thank you for that suggestion. We'll definitely consider that. And then we had another question that just came in.

Are there any provisions for emergency nighttime tasking, say less than 24 hour turnaround in response to extreme events such as wildfires? We do the best we can to get them submitted. There are instances that requests have been accelerated, but there is not a clear process laid out for that. The best information we can give is to submit it as soon as possible, and we'll get it submitted and approved in the most timely manner that we can.

Thank you. Jacob. And I'm just checking to see if there's any questions we've missed. All right. I don't see any more questions coming in. So we'll continue on with the webinar. It looks like that's all the questions we have for today. If you do have any additional questions later on about Landsat, Landsat special requests or any data, tools or services the USGS arrows provides, you can always email our team at that USGS gov email address on your screen.

I'd like to once again thank our speaker, Jacob, for his time and great presentation and our team in the background to help answer some of the questions you all had today. And I'd also like to thank you all again for joining us. We hope to see you at a future webinar. If you'd like to be notified of when our next webinar will occur, please sign up for the Eros User Services listserv by emailing Kesavan gov.

And I did see in the chat we have a question about our our slides available. We will be posting these online only to have the webinar recording that I'll get posted, and we'll make sure to post those as well. If you'd like a copy earlier, please email that serve and we'll send you a copy of the slides. Again, I want to thank you all for taking the time to join us today.

We'll stick around in case a few more questions get asked, or to capture some of those polling question responses. But with that, we hope you all have a wonderful rest of the day. Thank you for joining us. Hi Howard, I see your question about downloading the recording. We'll make sure that gets loaded onto the website here shortly. If you'd like, I can send you an email once the recording is live.

And I do see a question. It says, is there a land size limitation or number of path rows, or maybe a size that would affect likely overhaul approval? So there is no hard limit set. As I said, we've got those large campaigns looking over just about the entire western US during fire season. However, it ultimately comes down to the capacity of the satellites as well as our ground stations.

So if it is too large, it does run that potential of getting denied. But outside of those extremely large request, I've seen people submit requests for a dozen 22 dozen scenes, and those usually are processed without issue. Perfect. Thank you, Jacob. Hey, Fernando, I see your comment. Where can I go to review the PowerPoint? I had a conflict at the last minute.

I'll make sure to send you a PDF copy of the PowerPoint and if anyone else would like that, let me know and we can get that sent out to you as well. All right. I think we've captured all of the chat and the questions. So we're going to conclude the webinar. Thanks again, everyone for joining us. We'll see you the next one.

Thank you all.