Things To Know About Vector Data Model ?

What is Vector Data Model?

Vector Data model is important concept in GIS, It consists of point line and polygon features.

Image by Gerd Altmann from Pixabay

Point: features recorded as single x, y coordinate pairs or geographic location

imagesource: www.mapwindow.org

Line: features are an ordered series of connected line segments

image source: gis.stackexchange.com

Polygon: Features are an ordered series of at least 3 connected lines with same start and end point.

Image source: ArcMap Window

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GDAL & OGR (Importance & Installation)

GDAL & OGR libraries allow you to perform various GIS operations like, Flow Direction or working with DEM few raster & vector analysis outside GIS environment. Image by Gerd Altmann from Pixabay What Knowledge one should have : Basic Programming, Python What software you need : Python IDLE or command line, GDAL libraries files (explained later) Installation : 1- Once you have Python installed. 2- Start python IDLE to check which version of python you are using available at top as shown Python IDLE 3- Install two files available at link below based on your version of python. Download Link : http://www.gisinternals.com/query.html?content=filelist&file=release-1500-gdal-2-1-2-mapserver-7-0-2.zip Install first : gdal-201-1500-core.msi and then: GDAL-2.1.2.win32-py2.7.msi * Note specify the path C:\Python27\ArcGIS10.3\Lib\site-packages\ for GDAL-2.1.2.win32-py3.2....

Working With Raster Calculator In ArcMap

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 ...

“Rule Based Classification” using eCognition

Availability of high resolution satellite imagery leads to a growing number of change detection techniques and algorithms, research is done using remote sensing and GIS. In this tutorial, we build on the classification category feature set by introducing neighborhood relationships and topological functions. Secondly, we use relative elevation values and fuzzy rules for the classification systems. This study demonstrates that the rule-based classifier is a significantly better approach than the classical per-pixel classifiers & object based NN method . Image Source: NASA Methodology 1. Open the eCognition software. 2. Click on “create new project” option. 3. Import the “Study area image” from the workspace. 4. Assign weights to NIR band 5. Click on the layers and rename each layer. Layer 1 as blue, layer 2 as green, and 3rd as red and 4th NIR. 6. Go to “Process” option on t...

Learning Object Based Classification Using eCognition

Object Based Classification Using eCognition tutorials by GIS HIVE . ImageSource:PixaBay Lab 01 Performing Image Classification On High Resolution Data on Erdas Imagine Lab 02 Introduction to eCognition Basics Lab 03 Image Segmentation using eCognition Lab 04 Object Based Classification Using Standard NN eCognition Lab 05 Rule Based Classification using eCognition GIS HIVE intends to promote Geo Spatial Sciences awareness, for that purpose GIS HIVE has launched Youtube Channel . Here you can explore various Geospatial tutorials.

What is Radiometric Resolution Of Satellite Image

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

Generating Contours From DEM In ArcMap

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

GeoDa Free GIS Software

What is GeoDa : GeoDa provides analysis of various data formats like shapefile, GeoJSON, KML, SQLite and table format (CSV, XLS and DBF). Image by Pexels from Pixabay How it is related to GIS: It provides Geo-visualization, user can perform certain spatial analysis. Good things about GeoDa: GeoDa is an Open Source software, Along with Spatial analysis, simpler & complex statistical data analysis performed in excel (charting, graphing ) can be performed in GeoDa. Most suited for: It is most suitable for Students, Researchers. Downloadable link : http://geoda.software.informer.com/1.8/ imagesource: GitHub

Climate Change Not Myth But Reality

Northern Areas of Pakistan are blessed with beauty, we often hear people quoting these beautiful areas as “Switzerland of Pakistan”, “Heaven on Earth”, but these words proved there reality when for the first time I visited Northern Pakistan. It is worth mentioning that Pakistan is dependent on frozen hydrological resources. Many rivers such as River Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Indus, Shingo, Astor, and Jhelum are fed by runoff generated by melting of SC of Northern areas. Image by Aqsa kamran from Pixabay Image by Abdullah Shakoor2 from Pixabay This runoff supports agriculture . Agriculture of Pakistan is largely dependent on the snow melting phenomenon. Anomalies witnessed in glaciers and their melting patterns will have massive impact on hydrological resources because the country’s 70% of fresh water depends upon these frozen hydrological resources in the high mountains of Himalaya and Hindu Ku...

How To View Satellite Image In ArcMap

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...

OBJECT-BASED BUILDINGS DETECTION & CHANGE ANALYSIS USING MULTI TEMPORAL HIGH RESOLUTION REMOTE SENSING DATA

With urbanization and urban sprawl, land-use and land-cover change studies became an area of keen interest for researchers. Cause of rapid urbanization is peoples’ responses to economic opportunities, and government policies. New housing societies and business model adopted overall globe has provided opportunities for new land uses . Image by piviso from Pixabay “Image Classification is the process of sorting pixels into a finite number of individual classes, categories of data based on their DN (Digital Number) values”. With advent of modern high resolution era of satellite images, PIXEL based, Object based and many other machine learning algorithms have been developed. Currently the prospects of a new classification concept, Object-Based Classification , are being investigated. Recent studies have proven the accuracy of object-based classification over traditional classifiers. The object-based classification approach relies on basic...

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