# Beginner's GIS - VertNet

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Nov 12, 2013 (4 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

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
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

e.g. Infrared,

Aerial light
photography

Active
:

Sensor EM

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?

>

actual raster data

(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

?

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
-

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

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/