Spatial Analyst is a extension within ArcGIS that provides a range of spatial modeling and analysis tools.

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596 views

Performing a Multicriteria Analysis Using Distance Along a Road Network

There is the possibility that I will be working on a project which will look at thousands of properties in a region and measure their accessibility to different services (schools, parks, hospitals, ...
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1answer
299 views

GWR Result Issues

I am working with GWR to identify if there are any relationships between 'extreme' events and disease incidence. The use of GWR has been employed because I am working in a region where local ...
6
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1answer
279 views

Why does tool take longer to run when in Python script?

I have written a python script that does some euclidean allocation. For that I use arcpy.gp.EucAllocation_sa() method. Now, my python script takes 30-40% extra time than spatial analyst euclidean ...
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1answer
123 views

Substitute for SpatialJoin tool?

I have to write a script in Arcgis which I would like to use the SpatialJoin tool (arcpy) but I do not have the appropriate extension. It may be a tool (or example of scripts) for doing the same ...
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1answer
643 views

Modelling Sea level rise scenarios for a Coastal county in ArcGIS

I am a graduate student @ Clemson University and am working on a GIS based project which is to model different sea level rise scenarios and estimate its impacts on a coastal county and to suggest ...
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2answers
83 views

How to query points that fall outside their designated regions?

I have a shapefile with 250 points. Each point has a region attribute. In another shapefile I have all the possible regions with their names (it is polyline geometry). Unfortunately the coordinates ...
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1answer
852 views

What type of kernel density function does ArcMap use?

I know that there are several types of kernel density functions, such as uniform, cosine, Gaussian, etc. I was just wondering which one the "Kernel Density" functionality in ArcMap 10's Spatial ...
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6answers
6k views

Ways to Speed Up Python Scripts Running As ArcGIS Tools

This is a pretty general question. I just wondering what tips and tricks GIS programmers have used to speed up arcpy scripts that you import into the toolbox and run. I work most everyday writing ...
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2answers
308 views

Why would a perfectly usable raster mosaic produce an unusable clipped raster?

I'm getting funky results from Extract By Mask (spatial analyst). I'm clipping a Raster Mosaic of DEMs from the National Elevation Dataset with polygons. I have a script to run through 15 separate ...
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0answers
433 views

Output raster extents when using the Spatial Analyst Extract By Mask tool to clip a raster

I am using ArcGIS 9.2 and I have a simple python script that does the following : Loop over a polygon feature class (shown in red in the image below) For each record, create a feature layer to ...
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0answers
59 views

How do I make a path cross the most possible classes in a raster?

I want to create a function and possibly use Arcmap tools to create something similar to Cost Path. Instead of just choosing the LCP, it must cross through the most different integers. Let's say I ...
4
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1answer
415 views

Statistical analyses for survey against raster?

I am somewhat of a newbie to geostatistical analyses, but pretty familiar with GIS and remote sensing packages. I was wondering if anyone had suggestions on appropriate geostatistical analyses for a ...
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2answers
638 views

Floodplain generation given river section polylines, flood level elevation points and a DEM of the land surface

I am looking to generate flood plain polygons to represent 20 and 100 year flood zones, in the most accurate and efficient way possible, given the following datasets: 1) River cross section polylines ...
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2answers
1k views

Does a Zonal Statistics value change when applied on a subset of data?

I have generated zonal statistics using feature zone data on a value raster. This shapefile contains about 20000 polygons and the analysis went without a hitch. While testing quality, I ran the same ...
2
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1answer
178 views

Tabulate Area Errors

Having some issues with the tabulate area spatial analyst tool. Not sure why it's not working, but the output table is missing zones from the input feature class that defines them. I have a simple ...
2
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1answer
546 views

How to design a road with a certain slope

Is there a way that you want to connect two different points of altitude with a constant slope of 7% or another, to draw a line in the 3D model?
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0answers
452 views

How to assign values to a polygon layer based on nearest point in a point layer? [closed]

I have a point file depicting groundstations for rainfall measurment. I also have a polygon file representing districts of a state. I want to assign rainfall values in a particular district based on ...
4
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1answer
338 views

Trouble Tabulate Area

I am using Kansas Cropland raster data from NASS with tabulate area to find out acreage of different crop types. The python I used works fine for 2006-2009 (56 meter cell size), except 2010 & ...
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1answer
1k views

ESRI 3D Analyst: Which Graphics card?

in order to make the most of ESRI´s 3D analyst I would like to order an appropriate graphics card. I have been recommended the AMD FirePro V5900 2 GB by someone who doesn´t know much about GIS hence ...
5
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2answers
2k views

Viewsheds and Observer Points in ArcGIS Spatial analyst

I am trying to understand the viewshed and observer points tool in spatial analyst. I want to show which areas of land can see a wind turbine, or put another way, from where can the wind turbine be ...
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1answer
218 views

How to convert accuracy of DEM from 5 decimal places to 2

I had a csv dataset comprising of regular points containing elevation "z-values". I interpolated this using ESRI´s spatial analyst using the IDW method to produce a continuous raster surface. I set ...
3
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1answer
240 views

Estimating cline width at multiple points along a trait gradient

In the map below I have 66 (green) points along the midpoint (0.5) for an allele frequency cline across the region (see map). I created the points by placing a point every 25 km along the 0.5 allele ...
4
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1answer
1k views

How should I correctly exaggerate a hillshade raster (ArcGIS10, Spatial Analyst)?

I once wanted to generalize a high resolution raster and instead of MEAN i accidentally selected the default SUM technique, using a cell factor 5 (Lidar DEM is 1m resolution). When I used this result ...
2
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2answers
163 views

Spatial analysis? Two layers?

One is LandPlot and the other is Soils. When I open the LandPlot attribute table I see I have 500 specific plots of land. When I open the Soils attribute table I see I have 5 types of soils (let's ...
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1answer
172 views

Creating Home ranges (MCP) of marine mammals excluding solid land

I use ArcGIS 9.3 and the Hawth's tools for Home range analyses. I try to create MCP of marine mammals which all works fine. However, the MCP include some land as well. How can I create a MCP so that ...
3
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2answers
139 views

How to find the distance within which a set percentage of features fall?

Someone asked a question earlier about finding the number of features within a certain distance of another feature in ArcView. I have the opposite question: is there any way, in ArcGIS 10, to find the ...
5
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1answer
2k views

How to calculate stream order for vector data without a DEM?

I have a shapefile which contains the streams that were digitized from a satellite Image. I would like to calculate the stream order for this data. The data does not exactly match the DEM that I have, ...
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0answers
433 views

How to calculate Solar Radiation falling on vertical surfaces using DEMs and ArcGIS?

I am using ArcGIS10 Area Solar Radiation tool to calculate irradiation on horizontal surfaces (building roofs) but need to do the same for vertical surfaces (building facades). Any ideas on how to do ...
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1answer
466 views

How to use (make sense of) results from ArcGIS Area Solar Radiation tool?

I am using the tool Area Solar Radiation in ArcMap10 to analyse DEMs of parts of a city (area equivalent to a neighbourhood). My goal is to calculate the average annual solar irradiation (Wh/m2) on ...
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195 views

slope and mosaic datasets

I was wondering if anyone has had any experience with combining multiple DEM’s into a mosaic dataset. I am working with several DEM’s and need to convert them to slope. I’m having an issue with ...
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3answers
973 views

How to combine corner-touching polygons into a single feature

I have created a polygon layer from rasters, and only have a single classification ID (and calculated acres) for each polygon. I would like to "dissolve" all touching features into larger, individual ...
2
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2answers
2k views

Raster Combine - ESRI Spatial Analyst

I am trying to combine a whole bunch of rasters with Esri Spatial Analyst. Seems to be doing what I want EXCEPT the calculated output is only the area where all 4 rasters overlap. I am a complete ...
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1answer
519 views

Aggregate Data between Polygons

I have data at the ZIP3 level and I need to join it to a state file. I also need the data within the zip3 file to be averaged, but for some reason when I use the join tools, i'm not getting the ...
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2answers
266 views

Spatial Analyst - Contouring a range only

I have a grid (in .img format) with pixel values ranging from -10,000 to 10,000, which i would like to contour. but i would like to contour only -3000 to 0 range. is this possible to set this up ...
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3answers
1k views

How does Nearest Neighbor Image Resampling work in ArcGIS?

I am trying to understand how nearest neighbor for the resampling of Image datasets works in ArcGIS. The output raster cell value is the value of the closest cell value in the input raster: In this ...
2
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1answer
479 views

Spatial Analyst tool Look up but in ArcView3.2

Is there any option how to do a Spatial Analyst tool "Look up" operation from ArcGIS 10 in ArcView 3.2? I have a grid with attributes and need to "extract" values from the table field (values from ...
9
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3answers
611 views

Creating raster by randomly choosing cell value from multiple overlapping rasters?

I'm using ArcGIS Desktop 10 with its Spatial Analyst extension. How do I combine multiple rasters into one, always choosing randomly from the values of overlapping cells? I have an image that may ...
6
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2answers
1k views

Can shaded relief be “blended” with DEM colour ramp in ArcGIS to produce a more visually dramatic result?

Not being able to use true transparencies with ArcGIS colour ramps where only solid colours are allowed has me always wondering about how to improve the look of the surface in my maps without ...
5
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1answer
409 views

How to create a field with a specified slope projecting from a 3D polygon

Im trying to figure out how to create a elevation raster from a known location (3D polygon) that projects at a specified slope (1%) for a specified distance(1-2 km). Does anyone have any idea how to ...
5
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1answer
321 views

How do I get the upstream distance to all points in a DEM from a single downstream point?

I want to get the upstream distance to all points in a DEM from a single downstream point. The goal is to create a "downstream distance to a point grid". This then would allow me to create "distance" ...
16
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3answers
669 views

Dealing with bridges and tunnels when modeling raster least cost paths?

I'm currently using ArcGIS 10 Spatial Analyst's Cost Path tool to model pedestrian routes. I have sidewalks, fences, buildings and a ton of pedestrian scale features, all combined into a cost surface ...
6
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2answers
778 views

What are best practices to compare densities and locations between two sets of points?

I have two sets of point shapefiles. They represent two different customer groups for a retail store. Shapefile A represents online customers, Shapefile B represents in-store customers. What I ...
4
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1answer
2k views

How do I add a hyphen to the Field Calculator to merge 2 columns?

I am trying to build a field calculator expression to merge two columns into one. I am looking for the word that makes it a range. Example: I have 2 columns in elevation, From and To. I want to ...
3
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1answer
466 views

How does cost allocation work?

Why, when I use the cost allocation function of Spatial Analyst, is space not allocated in all input source locations (as shown in image below)? In particular, the input raster has 18 spots while the ...
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2answers
622 views

arcpy.sa.Viewshed with OFFSETA

This is using ArcGIS10 arcpy with spatial analyst. I need to call Viewshed, but with an observer height set. I have tried using a Z-aware point feature set, but that only throws an error. I am ...
0
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1answer
205 views

Specific Spatial Analyst tools failing while running extension using ArcGIS server

I am having having trouble running ExtractValuesToPoints on a remote server machine running ArcGIS Server (with ArcInfo and Spatial Analyst installed). It fails and throws a standard COM error. I have ...
5
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1answer
693 views

Are special interpolation techniques required for weather data?

I've downloaded a series of weather observations from the local weather agency - it comprises around 1,000 points spread non-uniformly across Australia, with a greater density of points located near ...
3
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1answer
588 views

Strange Behavior in Focal Statistics

I am trying to calculate the maximum value in a neighborhood on a raster using the Focal Statistics tool for Spatial Analyst in ArcGIS 10. Using python, I loop though several different radii, with ...
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4answers
2k views

Where can I find examples of fuzzy logic applications in ArcGIS?

The last ArcGIS version (10) includes two arctoolbox tools for fuzzy logic (Fuzzy Membership, and Fuzzy Overlay). Does anyone know where can I find some examples showing how they can be applied? ...
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3answers
953 views

How to cluster points based on a kernel density?

I have a large dataset with 36k points representing commercial land uses, each with a field containing the square footage. I have run a kernel density analysis on this dataset, producing a raster ...