Posts Tagged “ArcGIS”
Aileen Buckley, at the ESRI Mapping Center, has released a new tutorial on creating what she calls “sun glints”. These are the reflective glows you sometimes see on water bodies in aerial photographs. In essence, it’s a tutorial on creating gradient fills in ArcMap – a neat effect that cartographers don’t get to use very […]
One of the keys to good database planning is correctly anticipating what type of data each field will hold. If a field is expected to only hold integers, it is best to make it an integer field instead of a float or double field. Doing so will save space and time, and the database structure […]
Part of the GIS Day 2011 festivities at Texas A&M University included a student poster display in Evans Libary on the main campus. There were 29 posters covering a wide range of GIS topics from various classes and departments. All 29 posters contained a scalebar, a legend, and a North arrow. But only three contained […]
If you divide your time between ArcGIS and QGIS, you may have noticed that they don’t use the exact same projections. For Northern Colorado, for example, ArcGIS offers “NAD 1983 HARN StatePlane Colorado North FIPS 0501”, while the best QGIS can do is “NAD83(HARN) / Colorado North”. When projection information doesn’t agree exactly, I get […]
When installing an evaluation copy of ArcGIS Desktop 10, you may receive an error message during authorization saying something like “7174: Authorization request for EVA123456 cannot be completed.” Trial and error suggests that this error is caused by a conflict with a previously authorized installation using a different evaluation code. Even though you may have […]
If you’ve ever needed to export a shapefile or feature class to a GeoJSON text file, there’s a handy ESRI-supported Python script available. It’s easy to install into your ArcToolbox, and works quite well: http://arcscripts.esri.com/details.asp?dbid=15545 So what is GeoJSON? JSON stands for JavaScript Object Notation, an encoding format for web object data. GeoJSON is just […]
The hypsometric contour interval on the classic USGS quadrangle maps is 40 feet. Although it’s not a nice round number, I think it looks fantastic at that scale. It’s good at representing many different terrain types. Which is why USGS contours have become a bit of a standard for many GIS and cartographic applications. But […]
If you ever get the opportunity to work with bathymetric data, you may encounter CARIS files. CARIS is an enterprise GIS suite that is well suited to marine and hydrographic applications. Many GIS offices don’t have access to CARIS, but that doesn’t mean the data is out of your reach. CARIS offers a free data […]
PostGIS is a wonderful suite of tools, which really anchors the open source web mapping toolkit. However, it doesn’t always integrate well with an ArcGIS desktop environment. One obvious source of conflict relates to projections – most of ArcGIS’s projections are infinitesimally different than their real world counterparts. As an example, consider the Washington North […]