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Questions tagged [terminology]

Indicates questions asking about the use and meaning of specific technical words in GIS.

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5 votes
2 answers
7k views

Which one is called inset map in this?

I am confused as to which one is technically the inset figure in the below map. I know an inset map is one which has more detail. But in this case which one is referred to as an inset map ...
1 vote
1 answer
62 views

How was the term 'Feature' originally defined in GIS? [closed]

Esri defines Feature as a cartographic term: [cartography] Any part of the earth's surface, or anything found on the earth's surface, that can be represented on a map. Features can represent various ...
0 votes
1 answer
1k views

Difference between Image layer and Tile Layer

what is the basic difference between Image Layer and Tile Layer? Apart from the documentation....which says below points ol/layer/Tile - Renders sources that provide tiled images in grids that are ...
8 votes
7 answers
2k views

Best definition for GIS today? [closed]

What is the best definition of Geographical Information Systems? Has the definition changed at all since I was taught it 10yrs back? The technology has changed a lot and it is more powerful than it ...
10 votes
2 answers
7k views

What is the difference between Ground Sampling Distance (GSD) and spatial resolution?

In research papers on remote sensing, I see some authors referring to spatial resolution (expressed as pixel/distance) and others to Ground Sampling Distance (GSD) (also expressed as pixel/distance). ...
5 votes
1 answer
1k views

Difference between control point, reference point, and tie point

I georeferenced a map using grid coordinate and road network shapefile (e.g. intersection vertex) as a control point. I didn't acquire a control point through the survey. I use "control point (...
14 votes
1 answer
2k views

What does context mean in PyQGIS?

When writing PyQGIS scripts, especially processing script and expression function, I come across the term context. I use it, but I don't know what all contexts mean actually. There are also Qgs***...
21 votes
1 answer
373k views

What is the difference between Vector and Raster data models? [duplicate]

From: http://support.esri.com/en/knowledgebase/GISDictionary/term/vector%20data%20model vector data model: [data models] A representation of the world using points, lines, and polygons. Vector models ...
0 votes
0 answers
50 views

What is name/terminology for area in .tif satellite image file which is blank space/not land?

I have some L2 satellite images from an MSI bundle, and I need to produce a mask over the area in the file which is not the image itself - the black part in the image below. What is the technical name ...
12 votes
5 answers
658 views

Define the "system" in Geographic Information System

When speaking or writing about GIS all too often the concept in peoples' minds for Geographic Information Systems can be rephrased as "the software for map data". While software is integral to GIS, ...
1 vote
1 answer
789 views

Computing visual "center" of irregular polygon

UPDATE: centroid is fine, my initial implementation was not weighing the edge length. With that fix all is well. I am using the centroid to render a marker in the "center" of a parcel, but ...
3 votes
1 answer
215 views

Naming convention for ways of defining direction

The following two conventions for defining direction are very common, but what are they called? 0 at north, clockwise 0 at positive x-axis, counterclockwise Background: I'm writing a function that ...
262 votes
11 answers
154k views

Difference between projection and datum

What is the difference between a projection and a datum?
2 votes
1 answer
74 views

What is origin of term "network" in Network Common Data Form (NetCDF) format specification

I see (on Wikipedia) that the NetCDF format evolved from a specification for storing multidimensional data called the "Common Data Format". Semantically... the word "network" has a ...
2 votes
1 answer
134 views

What do you call two isochrone maps that shows the intersection between two points as a "meeting" line?

I've learned today what isochrone maps are but now I sort of want to combine two isochrone so that a line forms right where the maps meet in the middle time wise. As in, if each point travels the same ...
3 votes
2 answers
152 views

Generic term for CRS axes?

We're making a light web front to a database, and I saw this in a test screenshot: Despite those coordinates being nowhere near North America, the "latitude/longitude" label for those ...
2 votes
0 answers
358 views

How do "layer", "feature", "attribute", "field", and "data provider" relate?

I'm new to QGIS, but familiar with Python and PyQt, and am trying to make sense of the terminology of "layer", "feature", "attribute", "field", and "data ...
1 vote
0 answers
20 views

Is there an equivalent term to 'imagery' in context with maps and cartography?

Is there an equivalent term to imagery in context with maps or cartography? Mappery seems not to exist. (I'm from Germany, and some miles away from being a native-English speaker) To explain that a ...
0 votes
1 answer
158 views

Difference and similarities between Intervisibility and Viewshed [closed]

I am just looking for what the difference and similarities for Intervisibility and Viewshed.
2 votes
1 answer
71 views

General terms for the Esri-terms "Layer" and "Feature Class"

I am familiar with these terms used by Esri: Layer Stores visual properties (color, symbols,…) does not store data (attributes, coordinates) links to a Feature Class (or raster data) Feature Class ...
17 votes
2 answers
23k views

What are LiDAR returns?

Can someone help with an explanation and some references, in order to understand the nature of return pulses within a LiDAR system.
1 vote
1 answer
132 views

Correct terminology to describe regular grid

What is the correct terminology to describe a regular grid of squares based on certain distance in latitude/longitude? I came up with this description: We used regular grid of squares measuring 10' ...
16 votes
3 answers
15k views

What does M-value represent?

I am trying to wrap my ahead around the meaning of the M-value. I read ESRI's dictionary definition here: https://support.esri.com/en/other-resources/gis-dictionary/term/m-value and was not able to ...
114 votes
7 answers
180k views

Differences between DEM, DSM and DTM?

I am listing some of the acronyms used in our work and had to stop to think about whether to list these together or separately: DEM: Digital Elevation Model DSM: Digital Surface Model DTM: Digital ...
16 votes
4 answers
23k views

Spatial data? Geodata? Geographic Data? Geospatial data? [closed]

What word indicates spatial data within the geographical and geological domains? In particular, what word is precise enough for a science journal article (i.e., formal prose)? Candidates might include ...
6 votes
3 answers
464 views

Do I necessarily need coordinates for spatial prediction?

Commonly, it is stated that spatial prediction is the same as spatial interpolation, i.e. the estimation of values based on the observations' location: y ~ lon + lat Others state, that spatial ...
9 votes
2 answers
2k views

Finding Similar Map Paths

I'm looking for an algorithm which, when given a particular route on a map with attributes such as incline/distance/shape/etc, can find a route which is similar (in terms of the attributes) but starts ...
1 vote
1 answer
46 views

Does the concept of a map service exist in ArcGIS Online?

I'm new to web GIS. I have created an ArcGIS Online account that contains: Web Maps Feature Layers (hosted) It is my guess that the term feature layer is a synonym for feature service. If that's ...
-1 votes
1 answer
189 views

Is climate a small-scale or large-scale process? [closed]

This might sound like a stupid question but it bothers me anyway: We distinguish small-scale maps like world-maps and large-scale maps like a map of my local neighborhood. So far, so clear. However, ...
2 votes
3 answers
10k views

What's the difference between "route" and "track" in OruxMaps?

What's the difference between "route" and "track" in terms of navigation? Is there a conceptual difference or only a technical one? For example OruxMaps treats the two terms differently: (source)
0 votes
0 answers
30 views

What is the term for creating a network from scratch?

As part of my PhD, I developed a simple way of creating a road network splitting up collected coordinates based on where they cross. I know the standard method is to use a shapefile (or similar) as ...
1 vote
1 answer
970 views

Meaning of 'bnds' and dimensions in OCO2 v9 L3 data product

I cannot seem to understand what, for example, 'lat_bnds' means? Same go for 'lon_bnds', lat/lon_dimensions. These values come from the structurally flat NCDF4, sourced from the JPL as a custom ...
1 vote
1 answer
84 views

What is getting nearest points between two different but overlaping datasets called?

I need some terminology help as I am still learning GIS. I have two datasets. One with the address of every fire and it's latitude/longitude of small census tract. One with the location of every ...
0 votes
1 answer
26 views

What is getting nearest points between two different but nearby (almost intersecting) datasets called?

I need some terminology help as I am still learning GIS. This is related to, but not the same as, What is getting nearest points between two different but overlaping datasets called? I have two ...
5 votes
1 answer
233 views

The term for determining the pixels of a raster image

I am looking for an english well-established term for determining: 1) invalid/nodata raster image pixels (№ 1 - black ones on the image below) and 2) valid/data raster image pixels (№ 2 - other ones ...
2 votes
1 answer
1k views

Is there an easy way to say -3.4028234663852886e+38?

A lot of our datasets have a nodata value that is, or close to, -3.4028234663852886e+38. Can anyone think of an easy way to say this out loud when we're discussing things? Even "minus three times ...
16 votes
1 answer
15k views

Difference between bounding box, envelope, extent, bounds?

Every time when I create a script to manipulate vector (point, line and polygon) in python I meet this doubt. What is the difference between bounding box (bbox), envelope, extent, bounds?
12 votes
1 answer
7k views

Raster vs Grid vs Lattice terminology?

I have a question about GIS terminology - what is the difference between grid and raster and grid and lattice - in theory?? I thought, that raster is regular network and value is in the cell and the ...
1 vote
1 answer
1k views

What is Time of Validity in a GPS System?

What is time of validity in a GPS system? For defining time of validity, there are only a limited definitions available. My interpretation for time of validity is the built-in system time (like on ...
1 vote
1 answer
74 views

What do you call this combination of two district maps?

My real-world problem is that I want to combine state House and Senate legislative districts so that a user can pick a region (not a point) on a map that is included in both their House and Senate ...
1 vote
1 answer
186 views

What does "faceting" mean in a geo/map context?

I saw some folks talking about "faceting" in relation to a map data display, what does this mean in general terms? Examples?
7 votes
1 answer
8k views

Difference between 'join' and 'merge'?

Suppose one wants to make polygons A and B, and their respective attributes to be one unique polygon C. What is this GIS operation called? Is there any difference in GIS terminology about "...
2 votes
2 answers
516 views

What is the proper name for the "Venn diagram" of a set of geometries?

Sometimes, you have a set of overlapping geometries, and you want to generate an output like this: Image taken from this answer. The resulting polygons have no overlaps; each region of space is ...
1 vote
0 answers
235 views

What is difference between BLOB and tile in GeoPackage?

I'm new to GeoPackage, but wrote some code that will read an image file into a buffer and I then insert that buffer into the GeoPackage as a BLOB. The image files are GeoTIFFs which contain latitude, ...
3 votes
1 answer
176 views

Interpreting cell coordinates from DEM?

I'm using Environment Agency DTM LiDAR data which I import into Mathematica in ASCII format to produce ground surface models, sections, etc. The process works fine, but I'm unclear whether the cell ...
4 votes
1 answer
211 views

What is the standard terminology for raster alignment?

I would like to identify two types of raster alignment (assuming SRS is the same), but I am unsure of the correct terminology for these (or whether there is even a 'standard')? First, there is 'pixel ...
2 votes
1 answer
1k views

What does percentile mean in simpleComposite of Google Earth Engine?

I was using 'ee.Algorithms.Landsat.simpleComposite' to composite images, but I'm not sure what does this 'percentile' parameter mean?
2 votes
2 answers
521 views

In ArcGIS can a feature set use multiple coordinate systems?

I'm new to learning GIS and ArcMap, but have some confusion about coordinate systems. I thought I understood that there are two main types of coordinate systems, Projected Coordinate Systems which ...
2 votes
1 answer
54 views

What part of the Census Block is the County?

I have a list of census blocks for California and I am trying to get the county for each row. If I have a census block of 60070004024003, which 2 digits make up the county FIPS?
2 votes
1 answer
253 views

Agreed Upon Name for Rows in an Attribute Table

Is there an agreed upon name for the rows in an attribute table, perhaps one that would apply across different GIS software platforms? Esri uses "records" here, for example. They also have the ...