Remote Sensing Terminology
The Landsat program is a series of American satellites that use the visible and infrared parts of the spectrum to record images of the Earth's surface. It is the longest running enterprise for acquisition of satellite imagery, and started back in 1972. The most recent, Landsat 8, was launched in 2013.
Landsat satellites are located in a polar orbit, which allows them to provide images of almost all of the Earth's geography. As the satellite orbits the Earth from pole to pole, it appears to move from east to west because of the Earth’s rotation. This apparent movement allows the satellite to view a new area with each orbit.
Determining land cover has become one of the most common uses of Landsat Imagery and remotely sensing generated images all around the world.
The LiDAR sensor produces a series of point measurements that consists of geographic location (X & Y) and height (Z) of both natural and man-made features, and can be further processed to produce several different products and integrated into a Geographic Information System (GIS).
Click here to learn more about LiDAR
The amount of energy returning to the sensor (known as backscatter) is dependent upon the topography, roughness, and dielectric properties (moisture). Areas of an image with low backscatter appear dark (such as water), while areas of high backscatter appear as light gray levels approximating white shades. By interpreting the various gray tones, textures and patterns, the user can detect information regarding to the regions geologic lithology and structure.
In much of remote sensing, the process involves an interaction between incident radiation and the targets of interest. This is exemplified by the use of imaging systems where the following seven elements are involved. Note, however that remote sensing also involves the sensing of emitted energy and the use of non-imaging sensors. Click here to learn more about Remote Sesning
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For this job we were based in the town of Rio Blanco of Matagalpa, or basically the furthest town east of Managua that is still on the pavement (even though our project was about 60 km further east … this was the closest town to base out of).
The town is about a three to four hour drive east of Managua (about 220 km) over a sub par highway, secondary roads and a few dirt road sections (with a lot of rough sections and construction). The roadway meanders through some small towns along with a wonderfully scenic mountainous background that helps make up for the long journey. Along the route we pass many bus loads of people, trucks topped with supplies (with and without people on the back), other vehicles, as well as various horse and cattle spread out along the side of the road.
Rio Blanco (Spanish for “White River” that may have got its name for the river of the same name that pours down from Cerro Musún – yet another extinct volcano) is apparently renowned for its simplicity and its surrounding natural treasures, witch one can easily appreciate, it is a rather busy little place that boasts a population of around 30 000. Just like most places in Nicaragua, poverty is clearly abundant here. The climate here is very humid and tropical, with heavy rains almost every day (or night) because it is what they call the Rainy Season here. It will be hot and sunny one moment, then maybe get a rain shower for an hour or so and then it can easily be back to sunny again.
The hotels in Rio Blanco are inexpensive but also not very glitzy, the one we are staying is the best in town I believe and it does have running water (no hot water though) and electricity too witch I am told not all hotels here actually do.
On the plus side it is much more of a town then the people in Managua seem to have given it credit, and although it certainly is a little bit different then most towns I have stayed in, it is not all bad. Perhaps a little rough around the edges but it seems to have all the necessary basics that we need to operate with. Gas stations, restaurants, little stores, a place to land and secure our helicopter etc. Rio Blanco is not in any travel guide so probably does not get many tourists, the people are pretty friendly but not used to dealing with outsiders from Canada (I think just bible pushers mostly) very much so we do get a lot of attention .
We have been living on local dishes such as gallo pinto (a mixture of rice and beans), grilled beef (carne) or chicken (pollo) a small salad, cheese (cuajada) and fried plantains. Almost every restaurant here has the same menu so it doesn’t really matter where you go to eat. And there are three main beers (Toña, Victoria & Premium) witch turns out is almost cheaper then water and pretty common everywhere, I would even have to say that the locals drink more beer here then back home. A cold beer in a bar can go for about $1 to $2.
It is also funny to see cattle walk through the down town like every thing is normal, especially this one particular white cow that I have saw in town early in the morning at least 3 or 4 times.
to be continued …
Here is a video collage of photos from Rio Blanco (note: not by me), Nicaragua that I found on Youtube (has some Spanish music playing along with it, could be better with the volume turned down)
Well after a lengthy wait and battle to get the Nicaraguan Customs to finally get all their paper work sorted (or what ever the problem was) and release our equipment to us, we were able to get to work. And stop pretending to be American tourists or Gringos as the slang term here is.
We rented a hanger at the airport to use while we installed our LIDAR equipment onto the helicopter. Well actually it was more so a shelter from the sun then a traditional aircraft hangar as we would define it back home (… but glad to have it none the less).
Even came with indoor plumbing facilities :) although maybe not up to North American Standards. And I am sure it would never get used by any of the females that I know, or to tell the truth I couldn’t picture anybody using it !! .
Now that all was back in order as far as equipment is concerned and we have had the grand tour of this Central American paradise (or the western side of it) it is off to the Wild’s of Nicaragua along the east coast. Oddly enough I have not heard anything good about Rio Blanco nor any the other interior areas from anybody here in the city. People around here in Managua tell us that we will need hammocks, mosquito nets, a good 4×4, plus need to bring all of our own supplies etc. etc.
Maybe it will be a real Jungle expedition just like in the movies … “Indian Jones and the Raiders of the Lost Arc adventure here I come” …
Well with more time on our hands thanks to the Nicaraguan customs officials we set out for another tourist like tour of the country, but this time (after talking to the people at the hotel) we decided to check out other popular stops outside the city.
South of the City of Managua is the Parque Nacional Volcan Masaya, the countries largest National Park and one of several protected areas of Nicaragua. The Masaya is a shield volcano composed of nested about thirteen vents, calderas and craters composed of basaltic lavas and tephras (air borne material produced by volcanic eruptions). It formed over 2500 years ago by a basaltic eruption, since then a new basaltic complex has grown from eruptions from a set of vents that include the Masaya and Nindiri cones.
The Santiago crater is the one thatappears most active as it continually emits large amounts
of sulfur dioxide gas into the air and is the main attraction to most visitors to the park. The smoke is thick enough that it can easily be depicted from a satellite image. Climbing up to the edge of the Masaya crater provides an immaculate view of the surrounding country side as well as a picturesque nature view of the interesting flora and fauna that co exists within the crater itself.
A set of stone steps takes you to a high viewing point above the smoking Santiago crater and at the top is a large wooden cross called the Borbadilla cross that was planted near the border of the crater in order to exorcise the devil, because it was believed that this was the entrance to hell.
Easy to understand why people could think of something like this. I am not sure if the Volcano had anything to do with it, but the day that we visited the park felt like one of the hottest days of the trip so far and I ended up with a bit of a sun burn as well. So needless to say I had no problem leaving and heading to our next stop on the trip.
Borbadilla cross & stone steps leading up to the edge of the Santiago crater
(Image on left is from the Space Shuttle source and the image on the right is from Google Earth)
So our tour continued ( see previous post) around the city of Managua stopping at various historic and modern sites including some of the ones noted below.
We stopped down along the waterfront of Lake Managua to check out a few sites. First was the La Concha Acustica found close to Lake Managua is a large concrete sculpture resembling a large surging water wave that is about to crash upon the shore, we were told that it is has been used to stage concerts, political speeches, cultural and religious events like the visit from the Popes from the Vatican.
A large white obelisk monument is located with in the same park and it actually has a picture of Pope John Paul II on it. The site is where the Pope addressed the Nicaraguan people on his visit.
It does not look like there have been many events here recently ( … great place for a rock concert!) and kind of looks run down or maybe it is not well maintained. Lots of weeds growing around with garbage everywhere and there is a big ugly pink presidential billboard right beside the structure.
The Dennis Martínez National Stadium (it was the largest stadium in Central America at the end of its construction, it no longer the biggest but still the largest in Nicaragua) is a large baseball stadium named in honor of Nicaragua’s first Major League Baseball (MLB) player Dennis Martínez whom played for teams such as the Montreal Expos (I remember watching him back when I was a kid).
The building has these large arms that extend from the outside and then over the stands housing large lights for the games, at first glance we thought that the place was under reconstruction and these things might have been cranes or what not.
The stadium also serves as a venue for football (what we call soccer in North America) games, as well as concerts and other events (I doubt that Hockey is on that list). It is one of buildings that survived the large 1972 earthquake. Baseball is Nicaragua’s national sport and the stadium is where the Managua’s Boer’s team plays. There was no event going on at the time nor was the facility open so we could only google from the out side and only wonder what the Managua’s Boer’s games would be like. I noticed that there was not much room to park so it must be pretty busy place on the streets come game day.
This place continues to amaze me everyday because although it shares many similarities to Canada it still has many differences (makes me feel like I have stepped back in time sometimes …). For instance it is pretty common to have a horse and buggy going down any main street, 3 or 4 people riding on a small motorcycle or even a group of people riding on the back of a pick up truck.
We ventured on over to the El Huembes Market, a large place that houses thousands of little vendors and people, here they sell everything from food, souvenirs, cosmetics, house wares, clothes, hardware to hammocks, rocking chairs and many other local craft items.
It was extremely large, busy and easy to get lost, as there are many little hallways and corridors with vendors tucked in everywhere however apparently is only the second largest market in Nicaragua (The other one must be pretty big …). Every body you see here wants to sell you something and they often do not like to take no for an answer and sometimes drop the prices and what not. However some things no matter how cheap they may be, I still do not want to buy them! (Like the guy walking around with various bottles of pills, he walks up to me and hands me a jar, that turned out to be Viagra pills!!! No thanks dude, my equipment works just fine :) ) What did I buy here at the market, well I got some small paintings and some beer t-shirts.
Every body here in this city tries to offer you some sort of service here in return for a little cash, wether it be the dude who stands to watch your truck for you, the squeegee kids, people who try to sell youstuff at your window while you wait for a red light or the children in the park that approach you with their palm masterpieces in exchange for some coins.
Eventually we finished up, stopping at a local restaurant for some Nicaraguan style food (Carne a la Planche etc) and then returned to the hotel for some local drinks by the pool. While Nicaragua Customs takes thier time processing our equipment that we need to complete the job here.
… tough job but hey somebody has to do it …
So unlike most of my jobs that I normally get sent on, this particular one has provided me with an abundant amount of free time due to some security / customs issues involved with our survey gear (fortunate for me, not so fortunate for our company), so I have had amble time to explore the city and it’s culture. Some of the things that I explored were …
After visiting every province of Canada and almost every state in the United States during the past three years, I have finaly embarked upon my first international trip (not including USA travel …), to the country of Nicaragua, the largest state in Central America bordered by Honduras to the north and Costa Rica to the south.
This is a Helicopter based LIDAR acquisition job surveying for the construction of a hydro dam to be built in the inner central-east part of the country and involves a few stops in various places with the first stop in the city of Managua, the capital Nicaragua and also the largest urban center of Nicaragua, located on the southwestern shore of Lake Managua. The city has a population of about 1,680,100 million people and it is a very busy place to explore.
After arriving in the country and leaving the Managua airport towards the hotel, a person can easily get the wrong impression about this city as the drive goes through a pretty poor lower class district with numerous run down buildings, lots of people on the streets etc. But as you slowly make your way into the core of the city you find that Managua has plenty to offer and although may appear somewhat behind the times quite often (compared to North American standards), it still has all the modern features that one would expect from a major city like shopping malls, hotels, casinos, restaurant chains and much more.
The city of Managua has experienced the rise and fall of many political powers throughout it’s history and has also suffered some devastating earthquakes over time both of witch are evident in the urban surroundings. Currently it is the economic, political, commercial and industrial center of Nicaragua with plenty to offer it’s people and visitors.
What has made the trip even more interesting for me is my lack of knowledge of Spanish, the main language spoken here (I was told that there was plenty of English speaking people, if so I have yet to many of meet them yet … ). But just like many of my jobs working in Quebec and other non English based such areas, I have still managed to get by even though a lot of the time I have no idea what people are saying to me (just keeping it real…). On the other hand it is a great way to learn a new language and I have come a long way, since I first arrived here. So expect more blog postings from this interesting travel opportunity.