![]() ![]() Joins (append): when we have a one-to-one or many-to-one relationship between records 5 + 3 + 4 + 2 x 0 = 0 not suitable What does using model builder allow you to do? Run the same analysis in different areas and share the model with others What do the joins and relate functions do? We can append or access additional attribute information (tabular data) with joins and relates If the Boolean multiplier is 0, this removes unsuitable features from the analysis, regardless of their ranking Ranked variables (layers) are added and then multiplied by a Boolean variable(s) Some variables (layers) are classified and ranked (1-5) and some variables (layers) are Boolean (0,1) Spatial models involve the use of map algebra to integrate and analyze the data contained in two or more layers The three basic types of spatial models are? Boolean modelĬombined model What is a boolean model? Can be developed using either vector polygon layers or discrete raster layersįeatures in each layer are reclassified and assigned a value of 1 or 0ġ = acceptable (or suitable) What is a combined model? A combined model combines both the weighted model and the Boolean model Imagery is derived from digital airborne photographyĬommonly distributed as a county mosaic - image covers one countyĬan be color infrared (CIR), natural color (NC) or bothĭownload NAIP county mosaics from NRCS Geospatial Gateway or TNRISĭownload individual NAIP DOQQs from TNRIS What are some characteristics of spatial models? Developed as a decision support tool Normally 1 to 2 m resolution (pixel size)Ĭan be color infrared (CIR) or natural color (NC)Ĭan be used as a map background or as a source layer for digitizing featuresĭownload from TNRIS as DOQQs or compressed county mosaics (see below) What is a digital orthophoto quarter quad? High-resolution georeferenced and orthorectified digital imagery covering the U.S.ĭigital image covers one quarter of a 7.5' topographic mapĭownload from TNRIS (these DOQQs use either Texas Orthoimagery Program or NAIP imagery) What is NAIP Imagery High-resolution georeferenced and orthorectified digital imagery for the U.S. Images are georeferenced and projected to UTM coordinates Orthorectified to account for terrain-induced changes in scale Usually refers to elevation contour lines - can also be hydrography, roads or other layersĭownload contours (called hypsography) from TNRIS What is a digital orthophoto quad High-resolution georeferenced and orthorectified digital imagery for the U.S.ĭigital image covers one 7.5' topographic map Scanned separate (raster image) is then vectorized to create vector lines - the DLG These are the same scanned maps used to create the Esri USA Topographic Basemap What are some characteristics of a Digital Line Graph Scanned separate (layers) from a 7.5' topographic map Mostly 1:24000, 1:100000, and 1:250000 scale topographic mapsĬan be used as a source layer for digitizing features - but most DRGs are datedĪvailable as individual 1:24K, 1:100K, 1:250K maps - or as a 1:24K county mosaic Images are georeferenced and reprojected to UTM coordinatesĪ collared DRG includes marginalia on a topographic map What are some characteristics of Digital Raster Graphics Scanned digital image of a top map Widely used in hydrology to define watersheds boundaries and stream networks.ġ0m or 30m DEMs. What are some characteristics of a digital elevation model? Raster elevation grids used in the analysis of topography.Ĭan be used to create contour maps, slope maps, aspect maps and hillshades. What are some characteristics of maps from Google? Tends to work well Are transportation maps usually up to date? No, the most up-to-date maps are usually privately held by companies What are 1 km DEM's appropriately scaled for? National, continental or global scale.
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