wwnick
  • Member for 11 years, 6 months
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Difference between projection and datum?
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205 votes

Geographic coordinate systems (lat/long) are based on a spheroidal (either truly spherical or ellipsoidal) surface that approximates the surface of the earth. A datum typically defines the surface (...

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What is the current Web Mercator projection code?
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40 votes

This has been an annoying problem for a while, and hopefully will no longer be an issue. 3857 looks to be the current and correct code (I hope, that's what all my tile caches are in!). Update 9/7/...

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Trilateration using 3 latitude/longitude points, and 3 distances?
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39 votes

After some looking around at Wikipedia and the same question/answer at StackOverflow, I figured I would take a stab at it, and try to fill in the gaps. First off, Not sure where you got the output, ...

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Download Dataset From ArcGIS REST Service
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38 votes

That map service is a ArcGIS Server Dynamic Map service which typically only returns images and specific query results, much like a WMS. Some ArcGIS Server image services allow for data download, but ...

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Converting MapInfo TAB and/or MIF to SHP using free tools or ArcGIS for Desktop core product?
27 votes

George is correct, although for me, the toolbar is named ArcView 8x Tools. For TAB files, ogr is pretty handy as well, and will handle lots of formats - http://www.gdal.org/ogr/ogr_formats.html ...

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Splitting raster into smaller chunks using GDAL?
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20 votes

gdal_translate will work using the -srcwin or -projwin options. -srcwin xoff yoff xsize ysize: Selects a subwindow from the source image for copying based on pixel/line location. -projwin ...

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Listing available online WMS services (Weather, Land Data, Place Names)?
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18 votes

This question has been converted to Community Wiki and wiki locked because it is an example of a question that seeks a list of answers and appears to be popular enough to protect it from closure. ...

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Are there any convenient sources of color palettes to use in ArcGIS software while producing maps?
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17 votes

For thematic maps, the handy Colorbrewer has an ArcGIS plug-in, ColorTool The built-in styles also contain lots of professionally selected color palettes and ramps that you could repurpose for other ...

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Creating Vector Polygons with rendering performance like GISCloud?
14 votes

Looks like a very similar question was recently asked on the OSGeo Open Layers forum, with the GIS Cloud developers describing their approach, which is a interesting mix of GeoJSON geometries and ...

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Good websites for map-lovers?
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11 votes

This question has been converted to Community Wiki and wiki locked because it is an example of a question that seeks a list of answers and appears to be popular enough to protect it from closure. ...

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

SAGA has several fill methods http://www.saga-gis.org/saga_modules_doc/ta_preprocessor/index.html Flat Detection Sink Drainage Route Detection Sink Removal Fill Sinks (Planchon/Darboux, 2001) Fill ...

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Establishing survey marks
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8 votes

In order to establish a mark of a particular order, you have to design the survey so that it meets all the Class and Order requirements (listed in the standards) AND meet the error requirements, which ...

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Converting XYZ files (with regularly spaced xy) to ESRI GRID format?
8 votes

Sounds like you're wanting to do this in batch (don't blame you) As STH said, looks like Global Mapper will indeed do batch conversions. Nice price as well. FME Desktop can do using the ...

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Where can I find latitude and longitude data for the borders of U.S. Congressional districts?
6 votes

National Atlas has the district boundaries in shapefile format, then it's fairly simple to use ogr2ogr to convert the shapefile to KML, JSON, GML, CSV, or other format

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Given a list of surveyor points, what is the algorithm used to simplify the points and retain the terrain characteristics?
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6 votes

Seems like the picking key points portion of generating a TIN could suit your purposes. Here's a nice discussion on TINs, with three algorithms for picking key points. Survey of Polygonal Surface ...

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Background reading on using GPUs for GIS?
6 votes

Part of the ESRI Applications Prototype Lab's DevSummit presentation was on GPU for GIS. The video link appears to be borked, but a lengthy blog post contains a good summary and introduction to GPU ...

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How to handle time-based raster data in the ArcGIS Server JS API
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5 votes

The new mosaic datasets are time-aware and can be published as image services (requires Image extension) Esri has a javascript sample , and if you look at the image service details you can see that ...

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Multiple labels for 1 point
5 votes

I've done similar by having multiple instances of the layer. Add the point layer twice, and have one instance with the mapID label, the other with the school name label.

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Cutting features to do opposite of clipping in ArcGIS Desktop?
5 votes

The ET GeoWizards toolset contains an Erase tool similar to the ArcGIS Erase, Erases a feature layer with the features of a polygon layer and is one of the free functions available to ...

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How can I tell what licensing level my ESRI GIS server is from client tools?
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5 votes

This may not be a license issue, in Esri parlance, database servers are SQL Server Express instances only. ( help doc ) To connect to a full SQL Server DB, you need to make a database connection. ...

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Merging DEMs or other raster datasets and clipping Raster dataset to vector line?
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5 votes

I've never used the PLTS tools, and the help doesn't really give much info on how the Merge Raster Datasets works, but the Mosaic to New Raster geoprocessing tool, in the Data Management Toolbox under ...

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Identifying layers from multiple ArcGIS Server instances using ArcGIS API for JavaScript 2?
4 votes

The identify task can only reference one map service, so you will have to either: Put all the layers you wish to run Identity on in one map service Run multiple IdentifyTasks per map click I ran ...

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ArcGIS Online Topo Maps
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3 votes

It may not show up under the Basemap dialog, but Esri does host a US Topo map service. The service uses scale dependent rendering with 4 levels, a colorized shaded relief, 250k topographic, 100k ...

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What happened to the sample Portland gp services?
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3 votes

Looks like the whole Portland folder is gone from sampleserver2, and I didn't see any on ss1 or 3 either. Here are a couple async gp services used in the Silverlight API samples Clip Counties ...

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Interacting with the Map after selecting a button/tool
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3 votes

Here are the methods to disable the built-in map events like drag to pan, double-click to zoom. Then you can use the navigation toolbar for some basic functionality and/or wire up your own custom ...

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How can I view a KMZ on an iPad?
2 votes

Best way I have found is to use Google MyMaps. From Google Map, click MyMaps(must be signed in to your Google account), and select 'Create a New Map' and 'Import'. You can upload KML/Zs up to 10MB(...

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Using ArcGIS Online Base Maps without Esri Software?
2 votes

I don't think so at this time. I'm not anything close to a lawyer, but my reading is that AGS Online services can only be used with "Software", meaning ESRI proprietary, and "...

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Loading map files using ArcGIS Silverlight API?
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2 votes

Loading shapefiles is possible using the ESRI Silverlight API Contrib library implemented by viswaug, and I've gotten this to work successfully with ArcGIS Silverlight API v2.0. Haven't seen any ...

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Using a ArcGIS Server Feature Service's addFeature method: Parameters?
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1 votes

The addFeatures method is part of the ArcGIS Server REST API, and while the ArcGIS Silverlight API uses the REST API to interface with ArcGIS Server, the two APIs don't correspond directly. If you ...

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How do you remove the title in the banner from the ESRI geoportal extension?
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1 votes

Like Brad, I don't see the banner text either, but for future edification: in \Tomcat\webapps\geoportal\catalog\skins\tiles\banner.jsp, comment out or remove out the .getSiteTitle line (line 21 for ...

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