GeoSpatial Knowledge Hive

GIS & Remote Sensing is widely used for studying Urban Dynamics Change. Many questions like what is %age increase in buildings in a city, what is direction of increase, etc.. etc.. This study explores urban change in Quetta District of province Balochistan,Pakistan.  Link for Project Image by Эдуард Ризванов from Pixabay LULC Image Of Quetta  District

Polar Beer will become first ever specie to "extinct " because of adverse effect of Global Warming Image by  skeeze  from  Pixabay   What Ecologist are doing : Ecologist are using Satellite Images, to count polar beer. What Issue they Encounter : Differentiating Polar beer from white rock , issue is solved in a sense that polar beer has moving motion while rocks are static. image source: Sci-News.com image source: My Travel Tales   

Scientist who want to study gravity can take help of GIS & Remote Sensing  Image by  mohamed Hassan  from  Pixabay   Which data set to use : Grace What it does:  It makes Detailed measurement of earth's gravity Investigates about Earth's hydro reservoir  Investigates physical changes earth encounters  Investigates Disasters Official site:   http://grace.jpl.nasa.gov/ image source: http://grace.jpl.nasa.gov/

Radiometric Resolution  is defined as magnitude of EM ( Electromagnetic Energy ) recorded by a sensor Units : Measured in Bits Formula: Each bit records an exponent Power of 2. 1 Bit= 2 2 Bit=4 4 Bit =16 8 Bit=255 digital values Note: 0 represents Black tone and maximum like 255 represents highest tone. image source  www.satimagingcorp.com 1 Bit will be Black & white 16 Bit will be colored 32 Bit will be more colored and will carry greater energy levels Higher Radiometric Resolution much variation in colors reflected. Image to left is of  higher radiometric resolution than that of Landsat below. image source: geoinfo.amu.edu.pl

Free Remote Sensing Software OSSIM Open Source Software Image Map What about OSSIM : Open Source Remote Sensing Software  Who Funds : US departments (Intelligence & Defense) Image Source: Pixabay  Specialty: Supports more than 100 Raster & Vector Formats, Plugin Option available  Suitable for: High resolution Imagery (Spatial) OSSIM APPS:  Command Line  Desktop Applications     What OSSIM say about itself:                                                                                                      Image Source:http://trac.osgeo.org/ossim/wiki Image Source:http://trac.osgeo.org/ossim/wiki

Visualize View From a Particular Point Using GIS  How many places are visible from your point, e.g. you want to construct a house how many places are visible from that sight.e.g. you want to practice shooting , how many visible spots can be shot from location (A Military Application)...likewise many other interesting applications can be performed using viewshed analysis. Image by  Tim Hill  from  Pixabay Performing ViewShed Analysis   Use any GIS software, e.g. i will use ArcMap, as a first step get data set of your area. DEM (Digital Elevation Model) that gives topographic information (lat, long, height) freely available online. A shapefile of your point of sight, which you can create it easily in GIS software Example :   plne , an elevation grid; and lookouts.shp , a lookout location shapefile. Step-1 : Start ArcMap , Add data  Search for Hillshade  and  specify  files plne or your grid file  Hillshade Tool...

Have you imagined how satellites have surrounded earth surface  Click   ESRI satellite Map  which beautifully visualizes all satellites surrounding earth. Image Source: ESRI Satellite Map

DigitalGlobe Free Product Samples What is the Resolution of sample imagery: You can almost see license plates with the 30 cm spatial resolution data from the newly launched Worldview-3 satellite. Download 30 cm product: Image source: http://www.digitalglobe.com/

Free Remote sensing Software   Why so special : Free and Open Source   Additional Features: Extendable Plugins, an open source option to ERDAS IMAGINE, RemoteView, ENVI, or SOCET GXP, What Opticks say about its features:                        image source: opticks.org Free and open source Supports the following file formats: NITF 2.0/2.1, GeoTIFF, ENVI, ASPAM/PAR, CGM, DTED, Generic RAW, ESRI Shapefile, HDF5, AVI, MPEG, JPEG, GIF, PNG, BMP Zoom, pan, rotate spatially large datasets Quickly layer GIS features, annotations, results, and other information over your data to provide context Many image display controls such as colormap, histogram, transparency, etc. Support for datasets larger than four gigabytes Analysts can quickly combine steps using graphical wizards Support for processing data in its native interleave of BIP, BSQ or BIL Get  extensions  to drop in new capabili...

Often we need to  construct  sites for storage of water , i.e. DAM and likewise.  ArcMap can provide you with few very easy steps that scientifically selects suitable site.  Image Source: PixaBay  What these steps are? These are just few clicks that can be performed in GIS Software such as ArcMap  Adding Digital Elevation Model Converting Layer to KML Flow Direction Flow Accumulation Creating a new Shapefile Snap Pour Point Watershed Calculation Software you need for this: -          ArcGIS 10.X  Data Set: -         Any DEM ( Digital  Elevation Model Data) available online of your area of  interest .      Adding DEM Start ArcMap Right Click on layers and select Add Data Browse to folder to Add DEM data set available with name .tif or any other of your AOI. Change Symbology to your desired style just for understanding p...

Image by  Karolina Grabowska  from  Pixabay   What is Hill Shade :  Hillshade  is a  shaded  relief (levels of gray) on a map, just to indicate relative slopes, mountain ridges, not absolute height.  S patial Analyst Tools -> Surface -> Hill shade and set the factor Z to a higher value to get a dramatic effect and leave the other parameters at their defaults (the following  hill shade  is produced with a Z factor of 10). The Azimuth of 315 (degrees) is the aspect that gets illuminated by the ‘ sun ’ and is shown as the brighter color.  This mimics a late afternoon effect.  The ‘altitude’ is the altitude of the sun on the slopes. Click OK . You should see an illuminated  hill shaded  view of the topography.  Image Source: Desktop ScreenShot You may have output something like  www.cartotype.com

Contours are a useful way to visualize topography and to create a map that can be printed in black and white, or that mimics the standard USGS topo maps. Image by TheAndrasBarta from Pixabay What you need: DEM data of your Area. Extract your area from online freely  available   DEM and select  Spatial Analyst Tools -> Surface -> Contour.  Select the inputs as follows, with a 100m or 50m contour interval: since 10 m might take time. and click  OK. Contour tool in ArcMap Output may be some thing like depending on color scheme. Go to properties and label elevation values for a good visualization. Image source:  en.wikipedia.org

Raster Calculator extracts information from a Raster Image, based on user requirements. Image by James Osborne from Pixabay Working with Raster Calculator To explore the highest elevation areas in your DEM raster e.g. select Spatial Analyst Tools à Map Algebra   Raster Calculator Tool  Raster Calculator Double click on the layer e.g. in my case it is  DEM_Layer or any raster of your choice,   to enter this into the ‘ search ’ window. Click on the “ > ” symbol e.g. and select a number less than the maximum elevation . Query can change based on your criterion.  This arithmetic raster operation will select all cells with values above the defined threshold. In the example below a threshold of 500m was used.  A new layer appears on your map. The majority of the map has a 0 value representing false (values below the threshold), and the colored region has a value of ...

Viewing Satellite Map in Arc Map " Are you  interested  to study satellite image, go to google and search for freely available online satellite images"  Image by  Daryl Govan  from  Pixabay   Download them, i have added tmrect.bil   named   imagery  here  Bands Added In ArcMap  Right Click tmrect.bil in ArcCatalog Select preview section and examine tmrect.bil What is tmrect: It is Landsat TM image with 5 bands . Right Click on tmrect and select properties All information of satellite image is available in Raster section. Explore tmrect.bil by expanding it you will see 5 bands in drop down Now Launch Arc Map Insert a new Data Frame by clicking on insert as shown Spatial Reference Dialogue  Now to Add Data Right Click Task Data Frame and click Add Data Select tmrect.bil a window “Unknown Spatial Reference” is dis...