2023-01-12 Cumulative Flashcards
Measurement of latitude and longitude
degrees
DD - decimal degrees (ex: 43.64-103.93)
DMS - degrees minute second (ex: 43*, 56’ 31.298 “N)
LANDSAT 1 ***
launched in 1972
satellite to study earth and its changes over time
contain overlapping photos
Multispectural Scanner (MSS)
oscillating mirror technique that had line scanners to observe earth
designed by Virginia Norwood
Virginia Norwood
‘Mother of landsat’
designed MSS which was on Landsat 1
geometry (relating to pixels)
where the pixels are
radiometry definition (relating to pixels)
what color the pixels are
World Reference System (WRS)
path and row system/grid satellites follow
satellite vs aerial photos
satellite images are more vertical than aerial photos and thus have a larger footprint
aerial/landsat images are normally lower resolution
radiometry (relating to LANDSATs)
LANDSATs see beyond the visible light spectrum
infrared allows for
-seeing beyond visible light
-showing vegetation (as bright white) vs cities (darker)
useful for using different bands for different uses
pansharpening
using pan bands to sharpen photos
vectors
creating/saving data about how to mathematically make pixels (as opposed to the pixels themselves)
Optical Character Recognition (OCR)
process of translating raster to vector through recognition of words/symbols
raster vs vector
raster
-more realistic
-more numerous because more realistic
-highlights/takeaway
-usually don’t have attribute tables
-in color
-more analog
vector
-have attribute tables
-can get complicate because raster can’t do many of vector’s properties
-more digital
Features that make vector more complicated: compound features
features that have multiple parts can be recognized by vector (ex: Michigan’s 2 parts)
Features that make vector more complicated: inclusions
ex: Le Soto in South Africa because Le Soto is a country within South Africa but isn’t a part of it
Features that make vector more complicated: topology
planar and non-planar
nodes where planar data overlap
advanced properties concerning overlap of information
ZOOM INTO INTERSECTIONS OF LINES TO SEE OVERLAPS/LACK THEREOF
spaghetti data: lines don’t connect
Features that make vector more complicated: undershoots/overshoots
ZOOM INTO INTERSECTIONS OF LINES
points and lines are either too far or not far enough to the desired location of intersection
snapping (on/off): correcting position of desired intersection
Landsat sensors/bands
different sensors process different wavelengths of the electromagnetic spectrum
bands are combined to create photos and refer to the part of the EM spectrum being shown
CIR
Color Infrared Imagery
RBD = NRG
Near infrared
visible Red
visible Green
denotes healthy vegetation with blue and more sparse areas with red
NDVI
Normalized Difference Vegetation Index
helps filter out higher levels of wavelengths/accounts for differences in brightness
between 0 and 1
vegetation renders white
unvegetated areas renders black/darker
stretching
darkening dark pixels and whitening light pixels to utilize a higher range of colors
levels
0, 1, 2 ; very raw > less raw
how raw are the data/levels of processing LANDSAT data
collections
Landsat collections
comparing changes in historical maps to see if changes occurred as a result of errors or time
major reprocessing of Landsat archives
ergonomics
repetition of actions
voice control
vibration
re-injury
stereophotography
works by giving each eye a different image
important for 3D photos and aerial photos to provide multiple angles of the same location
photos taken eye distance apart
pixel depth
how many bits of info per pixel on screen (in the form of black, grey or color)
1 bit
1 or 0
black and white
can be good with higher radiometric resolution
8 bit
greyscale
NOT BLACK AND WHITE
one dimension
DEM
digital elevation model
white and black pixels are elevated
24 bit
color
red, green, blue each get a bit
transparency
4th bit after red, green, blue
compression
recording the image with smaller bytes
lossy compression
degrades the image
JPEG
JPEG
bad with sharp letters
good with shapes of colors
can compress well
not as high quality as PNG
lossless compression
exac same pixels but mathematically recorded with fewer bytes
compressed image still looks the same, not degraded
tiff
tag image file format
can be used to store undegraded pixels
not for display.. for storage
PNG
for transparency and perfect colors
generally higher quality than JPEG
APNG: animated PNG
Geotiff
tiff with geographic information/data sets, FOR DATA
common and can be multiple files
Shapefile
NOT just one file, usually a folder
GPX
basic format for GPS data
KML/KMZ
google earth file/zipped KML text file
side car file
every tiff has a tfw which is a world file
if it ends with a ‘w’ (ex: .gfw) it’s a probably geographic info
