Using GIS for Analysis: Queries Re-classification Map overlay Real world Land use Elevation Parcels Streets Retail A sample of approaches:

Queries Aspatial Questions about attributes How many ___ are there? Which is the oldest? Which has the greatest land value? Could be answered with database software alone Spatial Questions about location, size, shape, distances, etc. Where is ___ ? Which is the longest US route within the county? Which is the most isolated golf course? Require a map – or GIS

Combination Queries Some queries involve 2 or more criteria (spatial or aspatial) For these, use Boolean operators: AND, OR, NOT

Combination Queries Which golf courses are in Mesa AND have 36 holes? In Mesa 36 holes

Combination Queries Which golf courses are in Mesa OR have 36 holes? In Mesa 36 holes

Combination Queries Which 36-hole golf courses are NOT in Mesa? In Mesa 36 holes

Using GIS for Analysis Queries Re-classification Map overlay

Reclassification Result of query is a new data layer Which land in Maricopa County is federally managed? BIA BLM BOR DOD FS FWS NPS

Query approach: Which land is managed by BIA OR BLM OR BOR OR FS OR FWS OR NPS? BIA BLM BOR DOD FS FWS NPS

Reclassification Approach: a New Data Layer Federally managed Other

Reclassification approach cellOwnership A1BLM A2BLM A3FS A4Non-fed CellOwnership A1Fed A2Fed A3Fed A4Non-fed Reclassification is often a step to get data ready for overlay analysis Data Table Before Reclassification Data Table After Reclassification

Using GIS for Analysis Queries Re-classification Map overlay

Map Overlay Ian McHarg (“Design with Nature”) – pre-computer advocate of map overlay

Map Overlay vs. Combination Query “Which Golf Courses are in Mesa AND have 36 holes?” Map overlay produces a new data layer

Map Overlay vs. Reclassification Which land in Maricopa County is Federally managed? BIA BLM BOR DOD FS FWS NPS Map overlay involves data from two or more layers

An example of a GIS analysis… GIS as a tool in fire management: Sequoia-Kings Canyon National Park

GIS as a tool in fire management: Sequoia-Kings Canyon National Park Question: “Where should we do controlled burns, in order to best reduce the risk of severe out-of-control wildfires?” Several aspects to consider: Ecological need (natural fire interval) Human value: Infrastructure, human life & safety Hazard: ability to control a fire, once started Risk: based on historic record of wildfire occurrence

Analysis to determine ecological need Data available: Vegetation ClassificationRI max 1 - Ponderosa Mixed Conifer6 2 - White Fir Mixed Conifer Red Fir Mixed Conifer Lodgepole Pine Forest Xeric Pine Forest Subalpine Conifer Foothills Hardwood & Grassland Foothills Chaparral60 Maximum average interval for fire occurrence 1.Natural Occurrence of fire, by species, based on analysis of tree rings

Analysis to determine ecological need Data available: Ponderosa forest 2.Vegetation map

Data available: Analysis to determine ecological need 3.Historical fires

Analysis steps: Departure from natural fire interval Vegetation types Reclassify Overlay Fire return interval Date of last fire Reclassify Years since last fire FRI TSLF Analysis to determine ecological need

Analysis steps: Departure from natural fire interval Reclassify Ecological need for burn Departure index Need to burn <-5Extreme -5 to -2High -2 to 0Moderate > 0Low Analysis to determine ecological need

Map of ecological burn need

Additional steps …. Where to do controlled burns Ecological burn need Ability to control burn Vegetation types Types of fuel slope elevation Date of last fire

Where to do controlled burns Ecological burn need Ability to control burn Vegetation types Types of fuel slope elevation Date of last fire Infrastructure & Safety issues Risk of wildfire Additional steps ….

Today’s Challenges Environmental, Social, Political, Economic … Local, National, Global Information is an essential tool to address these issues Geographic technology can help to answer more complex questions covering larger geographic extents than ever before

Geographic information Involves a specification of location on the earth’s surface (WHERE) Also involves WHAT is at that location Goal is to uncover WHY something is located where it is