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

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5
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1answer
336 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
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3answers
535 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 ...
7
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1answer
8k 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
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1answer
324 views

When merging two DEMs, do they have to be in the same pixel bits?

I have a simple question. 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 ...
2
votes
1answer
400 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
638 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
913 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
4k 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
638 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
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6answers
6k 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
4k 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
551 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
241 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 ...
5
votes
2answers
6k views

NoData in ArcGIS Spatial Analysis

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 other ...
3
votes
2answers
545 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
819 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
752 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
876 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
748 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
vote
0answers
646 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
593 views

comparing two TINs

i have the following two files: 1) LiDAR las file1 2) 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
395 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, ...
5
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1answer
2k views

RMSE between two rasters step-by-step

Can anyone show how to calculate the RMSE (root mean square error) between following two rasters step-by-step and discuss on the obtained results' min and max values, and how to interpret it. Thanks a ...
6
votes
3answers
5k views

Clipping a raster using a polyline or polygon

I have a large raster created from values that cover the whole United States and Alaska which are both polygon and polyline features, this raster was caluclated using Spatial Analyst IDW ...
5
votes
2answers
149 views

Monitoring programmes

I am not sure if it is a right place to ask this one but let me try. Monitoring programmes are known for various targets and for various spatial levels. They may include regions, countries or even ...
6
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7answers
3k views

Extract raster values at points

How can I extract values from a raster by points. I prefer not in Arcgis. I prefer in Qgis or Mapwindow or other open source gis.
2
votes
3answers
998 views

How do you use Spatial Analyst Geoprocessing functions in ArcObjects in ArcGIS 10?

I'm trying to run some geoprocessing functions in ArcObjects. Some of the tools I want to use are part of the spatial analyst extension. In 9.3.1 it was fairly straightforward to follow the ...
7
votes
5answers
1k views

What type of interpolation should I use to visualize metal detection survey data?

I have about 500,000 points collected in a linear grid pattern over a 1 km2 area. The points were collected as part of a metal detection survey. Each point has X,Y and Coil Response mV (min -675.38 ...
1
vote
3answers
7k views

How to calculate Raster Area per Polygon?

In ArcMap, I have a raster file that contains 6 classes of landcover and a shapefile that is the census data (OA boundaries and their population). I want the area of each class in each OA? For ...
9
votes
4answers
1k views

Are there any open source tools to detect and fill sinks on a DEM?

Are there any open source or inexpensive tools to detect and fill sinks on a DEM? ESRI Spatial Analyst is just out of my price range.