Beginner's GIS - VertNet

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Nov 12, 2013 (3 years and 8 months ago)

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Beginner’s GIS

Biodiversity Informatics Training
Workshop

June 2012

Outline


What is GIS


GIS & Map Fundamentals


Spatial Data Types


Data Formats


Software


DEMO/Exercises

What is GIS?

GIS =
G
eographic
I
nformation
S
ystem(s)


GIS is a collection of computer hardware, software, and
geographic data for capturing, managing,
analyzing
, and
displaying

all forms of geographically referenced information.

Environmental Systems Research Institute (ESRI), 2007

What is GIS?

An “image” with attribute information

What is GIS?

Tool to make complex patterns simple



What is GIS?

Environment for integrating diverse data

Overview of spatial data

Raster and vector data collide

Overview of spatial data

Points, lines, and polygons

Vector data

Vector data


Shapefiles are common vector format of GIS
data

Shapefiles consist of 3 main components:

*.shp


main file stores geometry

*.shx


index of geometry

*.dbf


database of attributes

Shapefiles may also have:

*.prj


plain text file of projection

*.sbn and *.sbx


spatial index of features

*.atx


index of attributes

*.shp.xml


metadata

Vector data

Resolution

e.g. 4 x 4 km

Raster Data

General data issue: spatial scale

Decrease in resolution

Increase in extent

Spatial scale has two elements: resolution and extent

Resolution

Extent

In practice, resolution
and extent tend to be

inversely related

Resolution= cell size

Raster Data

15 KM
pixel

7.5 km per
pixel

4.5 km per
pixel

1 km per
pixel

Raster data
-

interpolation

Raster Data

Inverse distance

weighting

Kriging

Polynomials

Or Spline

Raster data
-

interpolation

Raster Data

Inverse distance

weighting

Kriging

Polynomials

Or Spline

Raster data
-

interpolation

Raster Data


Using linear
-
weighted set of
samples (greater
the distance, the
less influence on
output raster value)


Good for dense
sampling


Statistical method
that fits a function to
a radius of points,
assuming a spatial
correlation in
distance or
directionality


Interpolated surface
do not pass through
sample sites


Many different
types


Uses a
mathematical
function to
create a
minimize
overall surface
curvature


Sample points
pass through
surface


Best for
variables like
T

Raster data
-

interpolation

Raster Data

Environmental Data: conversion to raster

Weather station records

(vector point data)

Interpolated raster climate surfaces (grid)

WorldClim Method:
Hijmans et al. 2005

Gridded Climate Models are not just for climatologists any more…


Prism vs. Worldclim


Prism vs. Worldclim

Raster data
-

remote sensing

Raster Data

Raster data
-

remote sensing

Ned Horning, Center for Biodiversity and Conservation, AMNH

Raster Data

Raster data
-

remote sensing

Passive
:


Natural EM
radiation


e.g. Infrared,

Aerial light
photography

Active
:


Sensor EM
radiation


e.g. RADAR,

LIDAR

Raster Data

Common formats:


ESRI ASCII (.
asc
)


ESRI Grid


Geotiffs

(.
tif
)


Any raster file can be used as a GIS grid

Also:


MrSID


netCDF


BIL

Raster Data

Raster Data

What’s in an ESRI grid?


dblbnd.adf


hdr.adf


sta.adf


vat.adf


w001001.adf

>



actual raster data


w001001x.adf


prj.adf

(opt)


Vector v. Raster

Tradeoffs between the 2 types of data

Tradeoffs between the 2 types of data

Vector v. Raster

Software

GIS software

Win

Mac

GNU/ Linux

Unix

Web

CARIS

Y

N

Y

Y

Y

Chameleon

Y

Y

Y

Y

Y

ERDAS IMAGINE

Y

N

N

Y

N

ESRI ArcGIS

Y

N

Y

Y

Y

DIVA
-
GIS

Y

Winebottler

N

N

N

GeoServer

Y

Y

Y

Y

Java

GeoTools

Java

Java

Java

Java

N

GRASS

Y

Y

Y

Y

via
pyWPS

IDRISI

Y

N

N

N

N

ILWIS

Y

N

N

N

N

JUMP GIS

Java

Java

Java

Java

N

LandSerf

Java

Java

Java

Java

N

Manifold System

Y

N

N

N

Y

MapInfo

Y

N

Y

Y

Y

MapServer

Y

Y

Y

Y

Y

Maptitude

Y

N

N

N

Y

Oracle Spatial

Y

Y

Y

Y

Y

PostGIS

Y

Y

Y

Y

Y

Quantum GIS

Y

Y

Y

Y

Y

Smallworld

Y

?

Y

Y

Y

SPRING

Y

N

Y

Solaris

N

TatukGIS

Y

N

N

N

?

TransCAD

Y

N

N

N

Y

TerraView

Y

N

Y

N

N

TNTmips

Y

Y

Y

Y

N

TransModeler

Y

N

N

N

N

ArcGIS


Commercial software, but ESRI Conservation Program grants
support non
-
profits with free licenses


ArcGIS is a suite of applications: ArcMap, ArcCatalog, ArcTools


Lots of extensions and interacts well with python and R stats with an
extension


Includes, web server, web services, online GIS, and freeware
(ArcExplorer)


DIVA
-
GIS


Free, not open source


Designed for niche modeling: Bioclim, Domain

uantum GIS


Open source,


Functionality from plugins in C+ or python


Access to GRASS and R routines


Some GIS Software Resources


DIVA
-
GIS


http://www.diva
-
gis.org/



Quantum GIS


http://qgis.org/



Free Geography Tools


http://freegeographytools.com/



GISLounge


http://gislounge.com/




FreeGIS.org


http://freegis.org/

Some GIS Data Resources


Climate Data:


http://www.worldclim.org/


http://www.prism.oregonstate.edu



Global Land Cover Facility


http://www.landcover.org/



EarthExplorer (US DEM, LC)


http://edcsns17.cr.usgs.gov/NewEarthExplorer/



USGS Seamless Viewer


http://seamless.usgs.gov/




Global Administrative Boundaries


http://www.gadm.org


Pearson and Dawson 2003

Global Ecology and Biogeography

Scale / Environmental Variable
Dependencies