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

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8
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3answers
1k 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
votes
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 ...
1
vote
1answer
562 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 ...
1
vote
2answers
283 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 ...
13
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3answers
2k 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
521 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
votes
3answers
727 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 ...
7
votes
2answers
2k 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
votes
1answer
490 views

Creating field with specified slope projecting from 3D polygon?

I am 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 ...
5
votes
1answer
367 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
votes
3answers
714 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
votes
2answers
854 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 ...
3
votes
1answer
1k views

Conditional reclassification of a raster

I am attempting to do a conditional reclassification of an NLCD land-use raster. I specifically want to reclassify all developed areas (classifications 22,23,24) that are near a road (classification ...
4
votes
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
votes
1answer
507 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 ...
1
vote
2answers
642 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
votes
1answer
224 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
votes
1answer
796 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 ...
4
votes
2answers
2k views

How to exclude outliers from raster using ArcGIS for Desktop?

I calculated terrain curvature from a DEM. The DEM I use is interpolated from point elevation data. Generally, the DEM seems to be good, but some artifacts from interpolation exist. Those artifacts ...
3
votes
1answer
642 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 ...
15
votes
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? ...
7
votes
3answers
1k 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 ...
3
votes
2answers
296 views

Performing statistical analysis of buffers?

I am doing a buffer analysis of incinerators and looking at the output areas within those buffers, is there a way of doing a statistical analysis of several buffers to see if there is a significant ...
5
votes
1answer
367 views

How to find upstream - lateral and downstream zones around urban areas?

I've a DTM and a shapefile of built-up areas. For a fire risk model, I've to find (within a defined buffer zone) two zones around built-up areas: one that is above/higher and lateral and the other ...
1
vote
3answers
565 views

What other tools can complete this exercise besides ArcGIS Spatial Analyst?

excel spread sheet here The objective in the exercise is to determine how many public computers are available per person as a result of spatial distribution of libraries and people. Part 1: Grid of ...
1
vote
3answers
2k views

Calculate XY Coordinate with “CalculateField” tool

I used model builder to build a model which can calculate the XY coordinates and it's perfect! However, when I export it to VBscript and run it in VBA it crashes.... The error happens at ...
4
votes
2answers
959 views

solar radiation calculation

I have tried to calculate solar radiation (whole year with monthly interval) for Portugal from an ESRI grid (27m DEM) in Arcgis10. It seems to work, however it takes much more than a week and in the ...
8
votes
1answer
10k views

creating a dem from contours

I have a large set of contours that I received broken down into several different subsets. I have merged most of the subsets together creating a larger set of contours in three different files. I have ...
4
votes
2answers
2k views

How can I compare two point shapefiles that contain lat/longs and compute distance?

Greetings everyone, I have 2 sets of point shapefiles in ArcGIS (group A and B), each set has around 1000 entries that contain lat/long. What I want to do is compare Group A against Group B and figure ...
5
votes
1answer
341 views

Merging two DEMs in different pixel bits?

I have 2 different Digital Elevation Modeling (DEM). One is the state DEM and has 30m and has 16 pixel bit. I have a couple of smaller DEM that has 30m but they have 32 pixel bit. I know how to merge ...
2
votes
1answer
418 views

How can you make RasterToASCII_conversion observe environment setting output cell size?

I have two rasters (an ESRI grid and an IMAGINE image) that differ in projection, extent and cell size. I want to convert the IMAGINE to an ASCII, and want it to have the extent, cell size and ...
3
votes
1answer
712 views

Solar radiation calculation from GTOP030 DEM image

Can you help me to calculate solar radiation from GTOPO30 DEM image at the 30 m spatial resolution. I'm trying to do this many times using spatial analysis solar radiation calculation tool in ArcGIS. ...
4
votes
1answer
1k views

How do I know if the DEM has z values?

How do I know if the DEM contains z-values ? By looking at the DEM's layer properties and it does not mention the z values. I then add it to the ArcScene and tried to find it..nothing... It only ...
6
votes
3answers
5k views

Finding nearest raster cell value based on vector point?

I have two layers in ArcGIS: One is a vector point and the other is a raster layer. I want to append the value of the raster data grid to the vector point. The problem is the vector point is away from ...
0
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0answers
655 views

Watershed / drainage network analysis; floating point or integer raster for input?

I am a little desperate to find a solution to my problem. As I have detailed in this post I am unable to create a detailed drainage network (and catchments) from high resolution LiDAR data. I think ...
13
votes
6answers
7k views

Methodology for creating accurate drainage networks (and catchments) from high resolution LiDAR DEM?

This is not the first time I've stumbled over this issue; it seems that I am unable to generate a correct drainage network model and the resulting catchments from full resolution (1m cells) LiDAR ...
3
votes
2answers
5k views

How do you set OFFSETA for a Viewshed in ArcGIS10?

How do I calculate height when attempting to do a viewshed analysis in ArcGIS10? I am able to create a viewshed analysis from a poly point file, however I need to calculate for the 80ft to 100ft tower ...
2
votes
0answers
602 views

Spatial Analyst Cell Statistics seems to give the wrong answer in ArcGIS 10.0

I have a script that calculates standard deviation for a list of grids using the Cell Statistics function in Spatial Analyst for ArcGIS 10.0 The syntax is this: stdevGrid = ...
4
votes
1answer
5k views

Thiessen Polygon delineation within a Feature

I am trying to create Thiessen (Voronoi) polygons, based on points within a defined shapefile extent. The output should be inclusive to the feature. The output I receive now is the rectangular area ...
2
votes
3answers
252 views

Trying to make the private land white overlay hillshade but

I'd like to have anyone's feedback on this draft map I created. Tried to make the private ownership white but since it's RGB is not near to 255. I've seen someone created this map similiar to it and ...
4
votes
1answer
1k views

Processing time using ArcGIS Hydrology toolbox tools in standalone Python script vs. ArcCatalog

My question is: what might cause the ArcGIS 9.3 Hydrology Toolbox Snap Pour Point and Watershed tools to run significantly slower in a Python script versus manually running the tools in ArcCatalog ...
6
votes
2answers
7k views

Dealing with NoData in ArcGIS Spatial Analyst?

When using Spatial Analyst I regularly have issues with NoData values cropping up in the data. Various tools appear to introduce NoData values regularly. These values then cause issues with ...
3
votes
2answers
558 views

interpolating values within a certain distance of points

Let's say I have a set of points representing bridges. I want to create a kind of "heat" map that would highlight areas within my study area that has many bridges in good or bad condition. I have a ...
7
votes
2answers
846 views

Process a raster with multiple geoprocessing tools in arcgis 10 using python - flow between processes

I'm writing a short python script that includes processing rasters with different geoprocessing tools in ArcGis 10, for example, the three processes below, is this best way to use multiple tools ...
4
votes
1answer
800 views

Checkout Spatial Analyst extention, ArcObjects code

Update After investigating more closely the CODE 2 sample below (at the end of this post), it does check out spatial analyst (sa) extension, however it does not reflect it in the Tools>Extensions ...
5
votes
2answers
976 views

Using an integer variable in where-clause in arcgis python script

I've seen some questions on this, but there seem to be many different answers... and none have seemed to work. I'm trying to include an integer variable in the SQL where-clause of a tool like this ...
3
votes
3answers
768 views

How do you produce a output table containing distances between mineral grains at various azimuthal directions?

I am using ArcGIS 10, the newest version and I am a senior at Western Carolina University and working on my senior thesis and the data set in which I have are images of mineral thin sections all ...
1
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0answers
684 views

two results of IDW in ArcMAP are different

i added the following points to ArcMAP using "Add XY Data". x,y,z 7,39,117 27,17,122 27,61,123 46,36,136 52,14,138 55,46,141 56,56,137 65,24,144 65,36,145 Changed raster output size in "options" ...
4
votes
2answers
675 views

Comparing two TINs created using ArcGIS for Desktop?

I have the following two files: LiDAR las file1 Let's give it a name LiDAR las file2, contains the same file1 data, where number of points randomly removed. So if file1 contains X number of ...
6
votes
2answers
402 views

Recommend text for Spatial Analyst? (ArcGIS)

Does anyone have a recommendation for a good reference/tutorial(s) on Spatial Analyst? The most recent I can find are from early to mid 2000s. Or has SA simply not changed much in 7 years? Thanks, ...