Aboutvahab48_Sajadi Expertise General questions on GIS theory and application.
Esri based GIS softwares including: ARCGIS , ARC/INFO, ARCVIEW, 3D Analyst, Network Analyst, Spatial Analist,Avenue programming language.
Experience I have been working on GIS for 13 years, on various GIS projects, teaching, programming and developing GIS models
Publications 1- Article entitled "Application of GIS in soil survey project", presented and published in the procceedings of GIS'95 International Symposium in Vancouver, Canada
2- Educational booklets on GIS theory and application
Question QUESTION: Hello, I need to estimate the distance of dozens of streams in a number of watersheds. Each stream (and it's tributaries) are composed of several segments. Is there an easy way to do this?I am actually a biologist and have limited Arc experience but I do have ArcInfo software. Please talk to me like I know nothing.
ANSWER: Dear Lisa,
First:what do you mean by "distance"?. Do you mean the length of streams?
If so, individualy or the sum total length of the streams?
Second: Do you mean you have ACR/INFO workstation? ARCGIS or ARCVIEW3.X?
Please let me know .
Vahab Sajadi
---------- FOLLOW-UP ----------
QUESTION: Hi. By distance I mean actual distance on the ground. For example, a mainsteam stream may be 5,000 m in length but is made up of several polyline segments on the map and each has it's own smaller distance (one segment might be 580m long). I need to add all of these segments to get the total length of the stream. I also need to add the length of all of the tributary streams to the mainstem in the same way to get total stream distance in the watershed.
I have ArcMap/Info version 9.2
Answer Dear Lisa,
A- If you don't have the length of each segment (reach) in the attribute table:
1- open attribute table of streams layer (right click on the stream layer's name and click on "Open attribute table)
(I am supposing you have ARCMAP opened, with the streams layer added)
2- add a field with the name of "LENGTH" . Select "double" as field type
3-right click on new added field "LENGTH" field name. A drop down list appears.
4- Click on "Calculate Geometry, and then "OK"
The Legth of each segment will be calculated, populating the field with length of all segments.
5- Again right click on "LENGTH" field name.
6- click on "statistics" on the drop down list.
A box apprear, in which you can see statistics of the length field , including sum, min, max, std, plus a frequency distribution curve
B- If you have the length of segments in the attribute table already, simply follow the procedure
from step 5 .
Good luck
Vahab
